#QAM Modulator and Demodulator

[semiconductorlogs]

Digital Demodulator IC Market: Packaging Technology Trends by 2025-2032

MARKET INSIGHTS

The global Digital Demodulator IC Market size was valued at US$ 345 million in 2024 and is projected to reach US$ 523 million by 2032, at a CAGR of 6.1% during the forecast period 2025-2032. The U.S. market accounted for 32% of global revenue in 2024, while China is expected to witness the highest growth rate of 8.1% CAGR through 2032.

Digital demodulator ICs are specialized integrated circuits that convert modulated signals into baseband signals for digital processing. These components are fundamental in decoding various modulation schemes including QAM, QPSK, and OFDM used in modern communication systems. The technology finds applications across television broadcasting, automotive infotainment, radio communications, and IoT devices, enabling efficient signal processing with reduced power consumption.

Market growth is primarily driven by the increasing demand for high-speed data transmission in 5G networks and the proliferation of digital broadcasting standards. However, design complexity in multi-channel ICs presents technical challenges. The Single Channel segment currently dominates with 68% market share, though Dual Channel variants are gaining traction in advanced applications. Key players like Skyworks and Analog Devices are investing in integrated solutions that combine demodulation with RF front-end functionality to address evolving industry requirements.

MARKET DYNAMICS

MARKET DRIVERS

Expanding 5G Infrastructure and Smart Devices to Accelerate Demand

The global rollout of 5G networks is creating substantial demand for digital demodulator ICs. These components are essential for processing high-frequency signals in 5G base stations and smartphones. With over 2.3 billion 5G connections projected by 2026, telecom operators are accelerating infrastructure investments, driving adoption of demodulator ICs. Furthermore, the proliferation of IoT devices requires advanced signal processing capabilities that digital demodulators provide. Major markets like China and the U.S. are leading deployments, with infrastructure investments exceeding $200 billion annually to support next-generation connectivity.

Growing Automotive Infotainment Systems Fuel Market Expansion

Modern vehicles increasingly incorporate sophisticated infotainment systems requiring digital demodulators for radio and satellite signal processing. The automotive IC market is projected to grow at 6-8% CAGR through 2032 as manufacturers add more digital features. Luxury vehicles now average 20-30 ICs for entertainment systems alone, with mid-range models following this technological adoption. This represents a significant opportunity, especially in dual-channel ICs which allow simultaneous processing of multiple signals.

➤ Premium audio systems in vehicles increasingly utilize digital demodulators for HD Radio, satellite radio, and digital broadcast reception, enhancing the driving experience.

The transition from analog to digital broadcasting worldwide also contributes to steady demand. Over 85% of television markets have completed their digital transitions, requiring demodulator ICs in set-top boxes and smart TVs. This creates replacement cycles as consumers upgrade older equipment.

MARKET CHALLENGES

Global Semiconductor Shortages Continue to Disrupt Supply Chains

The digital demodulator IC market faces persistent challenges from ongoing semiconductor supply constraints. Production interruptions during pandemic recovery, coupled with surging demand across industries, have created quarterly shipment delays. Lead times for certain ICs extended to 40+ weeks in 2023, forcing manufacturers to revise production schedules. Smaller firms particularly struggle to secure stable supplies, creating market consolidation pressures.

Other Challenges

Design Complexity Advanced demodulator ICs require sophisticated RF and mixed-signal design expertise. Shrinking process nodes below 28nm demand substantial R&D investment, with development costs for new IC designs often exceeding $10 million. This creates significant barriers for new entrants.

Testing Requirements Stringent quality control for RF components adds cost and time to production. Automotive-grade ICs require extensive temperature cycling and reliability testing, with qualification periods extending 6-12 months. These requirements limit production scalability during demand surges.

MARKET RESTRAINTS

Design Integration Challenges Restrain Adoption

System integrators increasingly demand single-chip solutions combining multiple functions, posing technical hurdles for demodulator IC manufacturers. Achieving optimal performance while integrating additional RF, DSP, and power management functions requires complex trade-offs. Many designs struggle with interference issues, forcing OEMs to use discrete components instead.

Additionally, the shift toward software-defined radios introduces compatibility challenges. While offering flexibility, these systems require demodulator ICs with exceptional programmability and dynamic range – specifications that add 20-30% to component costs. This creates adoption resistance in price-sensitive consumer applications.

MARKET OPPORTUNITIES

Edge AI Integration Opens New Application Frontiers

The convergence of RF signal processing with edge AI presents significant growth potential. Digital demodulators enhanced with machine learning algorithms can dynamically optimize signal reception based on environmental conditions. This proves valuable for:

Smart city infrastructure monitoring

Industrial IoT condition monitoring

Next-generation satellite communication systems

Leading manufacturers are developing AI-enhanced demodulators that reduce power consumption by 15-20% while improving signal integrity. These innovations create opportunities in emerging markets like private 5G networks and automated industrial systems.

The defense sector also presents opportunities as modern electronic warfare systems require advanced digital receivers. Military RF applications accounted for nearly 20% of the high-performance IC market in 2023, with projected growth of 8-10% annually through 2030.

DIGITAL DEMODULATOR IC MARKET TRENDS

Increasing Demand for High-Speed Data Transmission to Drive Market Growth

The global digital demodulator IC market is experiencing robust growth, propelled by escalating demand for high-speed data transmission across telecommunications, broadcasting, and consumer electronics sectors. In 2024, the market was valued at $million and is projected to expand at a CAGR of % to reach $million by 2032. This surge is largely attributed to advancements in 5G infrastructure, where demodulator ICs play a critical role in signal processing efficiency. Particularly, the television segment holds a significant market share due to the ongoing digital transition in emerging economies.

Other Trends

Miniaturization and Integration in Semiconductor Design

As semiconductor technology evolves, there is a marked shift toward miniaturization and integration of demodulator ICs into multi-functional chipsets. Leading manufacturers are investing heavily in System-on-Chip (SoC) solutions that combine demodulation with other RF functionalities, reducing footprint and power consumption by up to 30%. This trend is particularly dominant in automotive applications, where space constraints demand compact designs without compromising signal integrity.

Emergence of AI-Optimized Signal Processing

The integration of artificial intelligence in demodulator ICs is revolutionizing signal processing capabilities. AI-enhanced algorithms now enable real-time adaptive demodulation, improving error correction rates by over 40% in noisy environments. This technological leap is critical for satellite communication systems, where maintaining signal clarity amidst atmospheric interference remains a persistent challenge.

While North America currently leads in market share at $million, Asia-Pacific is projected as the fastest-growing region, with China alone expected to reach $million valuation. This regional shift coincides with increased semiconductor manufacturing capacity and government investments in digital infrastructure across developing nations.

COMPETITIVE LANDSCAPE

Key Industry Players

Strategic Product Innovation Defines Market Leadership in Digital Demodulator IC Space

The digital demodulator IC market exhibits a moderately consolidated structure, dominated by established semiconductor players with specialized RF and mixed-signal expertise. Skyworks Solutions holds a prominent position, capturing approximately 18% revenue share in 2024, owing to its comprehensive portfolio spanning single and dual-channel demodulators for broadcast and telecommunications applications.

Analog Devices Inc. (ADI) and NXP Semiconductors collectively account for nearly 30% of the market, with their advanced demodulator ICs seeing strong adoption in automotive infotainment systems and digital television receivers. Their success stems from vertical integration capabilities and patented signal processing architectures that improve noise immunity in crowded RF spectrums.

Mid-sized specialists like MaxLinear and Cermetek MicroElectronics are gaining traction through application-specific designs, particularly in software-defined radio and satellite communication equipment. Recent product launches featuring adaptive equalization algorithms have helped these players secure design wins in 5G infrastructure projects.

The competitive intensity is further heightened by regional players like Nisshinbo Micro Devices and AltoBeam who are aggressively expanding beyond domestic Asian markets. Their cost-optimized solutions for consumer electronics are driving price pressure across entry-level market segments.

List of Key Digital Demodulator IC Manufacturers

Skyworks Solutions, Inc. (U.S.)

STMicroelectronics (Switzerland)

MaxLinear, Inc. (U.S.)

Analog Devices, Inc. (U.S.)

Cermetek MicroElectronics (U.S.)

IXYS Corporation (U.S.)

Infineon Technologies (Germany)

NXP Semiconductors (Netherlands)

onsemi (U.S.)

Nisshinbo Micro Devices Inc. (Japan)

AltoBeam (China)

Digital Demodulator IC Market

Segment Analysis:

By Type

Single Channel Segment Dominates the Market Due to Rising Demand in Compact Electronics

The market is segmented based on type into:

Single Channel

Subtypes: Low-power, High-speed, and others

Dual Channel

Subtypes: Synchronous, Asynchronous, and others

Others

By Application

Television Segment Leads Due to Widespread Adoption in Digital TVs and Set-Top Boxes

The market is segmented based on application into:

Television

Car

Radio

Industrial Automation

Others

By Architecture

Software-Defined Architecture Gains Preference for Its Flexibility in Multi-Standard Applications

The market is segmented based on architecture into:

Hardware-based demodulators

Software-defined demodulators

Hybrid demodulators

By End-User

Consumer Electronics Segment Leads Owing to Massive Adoption in Smart Devices

The market is segmented based on end-user into:

Consumer Electronics

Automotive

Telecommunications

Industrial

Others

Regional Analysis: Digital Demodulator IC Market

North America The North American Digital Demodulator IC market is driven by advanced technological adoption across industries such as telecommunications, automotive, and consumer electronics. With the U.S. leading the charge in 5G infrastructure deployment—backed by over $100 billion in private and public sector investments—demand for high-performance demodulator ICs is accelerating. Key players like Skyworks and Analog Devices (ADI) dominate the landscape through innovation in spectrum-efficient solutions tailored to next-generation networks. However, semiconductor supply chain constraints and stringent FCC regulations pose challenges for smaller manufacturers. The region’s focus remains on miniaturization and energy efficiency to cater to IoT and smart device proliferation.

Europe Europe’s market thrives on its robust automotive sector (accounting for 20% of global demodulator IC demand for in-car infotainment systems) and the EU’s push for digital broadcasting standardization. Companies like STMicroelectronics and Infineon leverage the region’s strict EMC directives to develop EMI-resistant ICs. The transition from analog to digital radio (DAB+) in countries like Germany and the UK further stimulates growth. Nonetheless, high R&D costs and competition from Asian manufacturers pressure profit margins. Collaborative initiatives such as the European Chips Act aim to bolster local semiconductor production, offering long-term stability.

Asia-Pacific Accounting for over 40% of global Digital Demodulator IC consumption, the Asia-Pacific region is powered by China’s electronics manufacturing dominance and India’s expanding broadcast infrastructure. Affordable single-channel ICs dominate sectors like budget televisions and radios, while dual-channel variants gain traction in premium automotive applications. Japanese and South Korean firms lead in technological advancements—Nisshinbo Micro Devices recently unveiled a low-power demodulator for 5G small cells. Price sensitivity remains a critical factor, driving mergers between local suppliers and global giants to optimize production costs. Urbanization and smart city projects present sustained growth opportunities despite trade tensions affecting chip supply chains.

South America This emerging market shows gradual adoption of Digital Demodulator ICs, primarily for television and radio applications amidst analog signal phase-outs. Brazil’s Pro TV 3.0 initiative aims to complete digital terrestrial TV migration by 2025, creating a $50 million incremental opportunity. Economic instability, however, limits investment in cutting-edge demodulator technologies, with most demand fulfilled through imports. Local assembly partnerships—such as NXP’s production facility in Mexico serving neighboring countries—offer a compromise between cost and quality. Regulatory inconsistencies across nations further complicate market entry strategies for global suppliers.

Middle East & Africa The MEA region exhibits niche growth driven by satellite TV adoption in rural areas and luxury automotive sales in Gulf countries. Digital demodulator ICs with enhanced signal recovery capabilities are prioritized to overcome infrastructural gaps in terrestrial networks. While the UAE and Saudi Arabia invest in local semiconductor testing facilities, most components are imported due to limited fabrication capabilities. Political instability in parts of Africa disrupts supply routes, though pan-regional trade agreements show potential to stabilize IC distribution networks over the next decade.

Report Scope

This market research report provides a comprehensive analysis of the global and regional Digital Demodulator IC markets, covering the forecast period 2025–2032. It offers detailed insights into market dynamics, technological advancements, competitive landscape, and key trends shaping the industry.

Key focus areas of the report include:

Market Size & Forecast: Historical data and future projections for revenue, unit shipments, and market value across major regions and segments. The global Digital Demodulator IC market was valued at USD 720 million in 2024 and is projected to reach USD 1.1 billion by 2032, growing at a CAGR of 5.8% during the forecast period.

Segmentation Analysis: Detailed breakdown by product type (Single Channel, Dual Channel), application (Television, Car, Radio, Others), and end-user industry to identify high-growth segments and investment opportunities. The Single Channel segment is expected to grow at a CAGR of 6.2% from 2025 to 2032.

Regional Outlook: Insights into market performance across North America, Europe, Asia-Pacific, Latin America, and the Middle East & Africa, including country-level analysis. Asia-Pacific accounted for 42% of the global market share in 2024.

Competitive Landscape: Profiles of leading market participants including Skyworks, ST, MaxLinear, ADI, and NXP, covering their product offerings, R&D focus, manufacturing capacity, pricing strategies, and recent developments such as mergers, acquisitions, and partnerships. The top five players held approximately 58% market share in 2024.

Technology Trends & Innovation: Assessment of emerging technologies, integration of AI/IoT in demodulation, semiconductor design trends, fabrication techniques, and evolving industry standards like 5G and advanced broadcasting protocols.

Market Drivers & Restraints: Evaluation of factors driving market growth (increasing demand for digital broadcasting, automotive infotainment systems) along with challenges (supply chain constraints, regulatory issues in spectrum allocation).

Stakeholder Analysis: Insights for component suppliers, OEMs, system integrators, investors, and policymakers regarding the evolving ecosystem and strategic opportunities in digital demodulation technologies.

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[sahilblogs]

QAM Modulator and Demodulator

QAM Modulator and Demodulator

QAM Modulator and Demodulator combine two amplitude modulation signals into a single data transfer channel is the technique of modifying any one characteristic (amplitude, frequency, or phase) of a relatively high-frequency carrier signal in proportion to the instantaneous value of the modulating signal or message signal is known as modulation. For example, the input data signals I and Q are…

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[workrockin]

How does wifi work behind the scenes?

The Physics

All wireless communication including wifi occurs due to electromagnetic interactions which is one of the four fundamental interactions in nature.

In simplest terms this means that a moving charged particle will have a magnetic field associated with it which will be perpendicular to the direction of charge.

[If charge is moving up and down the magnetic force will move sideways. If charged particle is moving sideways magnetic force will move up and down]

Similarly a changing magnetic field will have an electric force associated with it that will be perpendicular to the direction of the magnetic field.

[In the figure above the electric charge represented by E in red moves up and down the magnetic field represented by B in blue moves sideways]

As a result of electromagnetism the charged and magnetic particles move forever. On and on like a wave. An electromagnetic wave.

This wave exhibits both electric and magnetic properties.

So that if you transmit a wave ,generated by an oscillating current, through an antenna at point “a” you can receive it ,as an oscillating current, from another antenna at point “b”.

The Mathematics

Now an electromagnetic wave has certain properties that can be represented mathematically. These are

Wavelength — Length of the wave between to symmetric points. Such as length between highs and lows.

Frequency — Number of times the wave oscillates/repeats.

Amplitude — The max height of the wave. How high/low can it go. Amplitude is related to strength of the wave.

Phase — The value of a wave at a particular time and a point. A wave is constantly changing. The phase determines it at a particular instant.

These properties allow us to perform calculations on waves. We can add,subtract and compare waves just like we do with real numbers.

The engineering

Engineering solves the practical problem of transmitting useful information on a wireless wave.

It does that by modulating the signal with information before transmitting it via an antenna.

The receiving antenna extracts the current from the wave which can then be demodulated into the information that was transmitted.

Wifi is concerned with providing the physical channel for transmission of information and a mechanism for accessing that channel.

[In osi model this corresponds to layer 1 and layer 2]

Some points to note

Wifi frequency like 2.4 gHz causes the current to oscillate 2.4 billion times per second before the wave is transmitted. At the receiver this oscillating current is converted into digital bits that can be understood by computer.

Most modern wifi devices use QAM to modulate (or transmit useful information on) both Amplitude and Phase of the wave.

Wifi is a shared channel access. Meaning a single channel is shared by multiple devices (known as carrier sense multiple access) but only one at a time (for collision avoidance)

References

Nice video explaining the engineering behind wifi modulation

https://youtu.be/NbrRGBRk5fM

And some more articles explaining the engineering behind wifi

https://superuser.com/questions/298568/how-does-wi-fi-modulate-the-electro-magnetic-wave

https://documentation.meraki.com/MR/WiFi_Basics_and_Best_Practices/Wireless_Fundamentals%3A_Modulation

[felord]

EE2025 Programming Assignment 2 Solved

EE2025 Programming Assignment 2 Solved

You can use MATLAB, Python or any other tool for this programming assignment.

Objectives: In the previous assignment, you implemented a QAM modulator and demodulator and simulated the transmission of an image of Mona Lisa through an additive white Gaussian noise channel. In this assignment, we will improve the bit error rate (fraction of bits incorrectly decoded) using channel coding. We will see…

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300+ TOP MOST EDC LAB VIVA Questions and Answers

EDC LAB VIVA Questions :-

1. What is Electronic? The study and use of electrical devices that operate by controlling the flow of electrons or other electrically charged particles. 2. What is communication? Communication means transferring a signal from the transmitter which passes through a medium then the output is obtained at the receiver. (or)communication says as transferring of message from one place to another place called communication. 3. Different types of communications? Explain. Analog and digital communication. As a technology, analog is the process of taking an audio or video signal (the human voice) and translating it into electronic pulses. Digital on the other hand is breaking the signal into a binary format where the audio or video data is represented by a series of "1"s and "0"s. Digital signals are immune to noise, quality of transmission and reception is good, components used in digital communication can be produced with high precision and power consumption is also very less when compared with analog signals. 4. What is sampling? The process of obtaining a set of samples from a continuous function of time x(t) is referred to as sampling. 5. State sampling theorem? It states that, while taking the samples of a continuous signal, it has to be taken care that the sampling rate is equal to or greater than twice the cut off frequency and the minimum sampling rate is known as the Nyquist rate. 6. What is cut-off frequency? The frequency at which the response is -3dB with respect to the maximum response. 7. What is pass band? Passband is the range of frequencies or wavelengths that can pass through a filter without being attenuated. 8. What is stop band? A stopband is a band of frequencies, between specified limits, in which a circuit, such as a filter or telephone circuit, does not let signals through, or the attenuation is above the required stopband attenuation level. 9. Explain RF? Radio frequency (RF) is a frequency or rate of oscillation within the range of about 3 Hz to 300 GHz. This range corresponds to frequency of alternating current electrical signals used to produce and detect radio waves. Since most of this range is beyond the vibration rate that most mechanical systems can respond to, RF usually refers to oscillations in electrical circuits or electromagnetic radiation. 10. What is modulation? And where it is utilized? Modulation is the process of varying some characteristic of a periodic wave with an external signals. Radio communication superimposes this information bearing signal onto a carrier signal. These high frequency carrier signals can be transmitted over the air easily and are capable of travelling long distances. The characteristics (amplitude, frequency, or phase) of the carrier signal are varied in accordance with the information bearing signal. Modulation is utilized to send an information bearing signal over long distances. 11. What is demodulation? Demodulation is the act of removing the modulation from an analog signal to get the original baseband signal back. Demodulating is necessary because the receiver system receives a modulated signal with specific characteristics and it needs to turn it to base-band. 12. Name the modulation techniques? For Analog modulation--AM, SSB, FM, PM and SM Digital modulation--OOK, FSK, ASK, Psk, QAM, MSK, CPM, PPM, TCM, OFDM 13. Explain AM and FM? AM-Amplitude modulation is a type of modulation where the amplitude of the carrier signal is varied in accordance with the information bearing signal. FM-Frequency modulation is a type of modulation where the frequency of the carrier signal is varied in accordance with the information bearing signal. 14. Where do we use AM and FM? AM is used for video signals for example TV. Ranges from 535 to 1705 kHz. FM is used for audio signals for example Radio. Ranges from 88 to 108 MHz. 15. What is a base station? Base station is a radio receiver/transmitter that serves as the hub of the local wireless network, and may also be the gateway between a wired network and the wireless network. 16. How many satellites are required to cover the earth? 3 satellites are required to cover the entire earth, which is placed at 120 degree to each other. The life span of the satellite is about 15 years. 17. What is a repeater? A repeater is an electronic device that receives a signal and retransmits it at a higher level and/or higher power, or onto the other side of an obstruction, so that the signal can cover longer distances without degradation. 18. What is an Amplifier? An electronic device or electrical circuit that is used to boost (amplify) the power, voltage or current of an applied signal. 19. Example for negative feedback and positive feedback? Example for –ve feedback is ---Amplifiers And for +ve feedback is – Oscillators. 20. What is Oscillator? An oscillator is a circuit that creates a waveform output from a direct current input. The two main types of oscillator are harmonic and relaxation. The harmonic oscillators have smooth curved waveforms, while relaxation oscillators have waveforms with sharp changes. 21. What is an Integrated Circuit? An integrated circuit (IC), also called a microchip, is an electronic circuit etched onto a silicon chip. Their main advantages are low cost, low power, high performance, and very small size. 22. What is crosstalk? Crosstalk is a form of interference caused by signals in nearby conductors. The most common example is hearing an unwanted conversation on the telephone. Crosstalk can also occur in radios, televisions, networking equipment, and even electric guitars. 23. What is resistor? A resistor is a two-terminal electronic component that opposes an electric current by producing a voltage drop between its terminals in proportion to the current, that is, in accordance with Ohm's law: V = IR. 25. What is inductor? An inductor is a passive electrical device employed in electrical circuits for its property of inductance. An inductor can take many forms. 26. What is conductor? A substance, body, or device that readily conducts heat, electricity, sound, etc. Copper is a good conductor of electricity. 27. What is a semi conductor? A semiconductor is a solid material that has electrical conductivity in between that of a conductor and that of an insulator(An Insulator is a material that resists the flow of electric current. It is an object intended to support or separate electrical conductors without passing current through itself); it can vary over that wide range either permanently or dynamically. 28. What is diode? In electronics, a diode is a two-terminal device. Diodes have two active electrodes between which the signal of interest may flow, and most are used for their unidirectional current property. 29. What is transistor? In electronics, a transistor is a semiconductor device commonly used to amplify or switch electronic signals. The transistor is the fundamental building block of computers, and all other modern electronic devices. Some transistors are packaged individually but most are found in integrated circuits. 30. What is op-amp? An operational amplifier, often called an op-amp , is a DC-coupled high-gain electronic voltage amplifier with differential inputs and, usually, a single output. Typically the output of the op-amp is controlled either by negative feedback, which largely determines the magnitude of its output voltage gain, or by positive feedback, which facilitates regenerative gain and oscillation. 31. What is a feedback? Feedback is a process whereby some proportion of the output signal of a system is passed (fed back) to the input. This is often used to control the dynamic behaviour of the system. 32. Advantages of negative feedback over positive feedback? Much attention has been given by researchers to negative feedback processes, because negative feedback processes lead systems towards equilibrium states. Positive feedback reinforces a given tendency of a system and can lead a system away from equilibrium states, possibly causing quite unexpected results. 33. What is Barkhausen criteria? Barkhausen criteria, without which you will not know which conditions, are to be satisfied for oscillations. “Oscillations will not be sustained if, at the oscillator frequency, the magnitude of the product of the transfer gain of the amplifier and the magnitude of the feedback factor of the feedback network ( the magnitude of the loop gain ) are less than unity”. The condition of unity loop gain -Aβ = 1 is called the Barkhausen criterion. This condition implies that Aβ= 1and that the phase of - Aβ is zero. 34. What is CDMA, TDMA, FDMA? Code division multiple access (CDMA) is a channel access method utilized by various radio communication technologies. CDMA employs spread-spectrum technology and a special coding scheme (where each transmitter is assigned a code) to allow multiple users to be multiplexed over the same physical channel. By contrast, time division multiple access (TDMA) divides access by time, while frequency-division multiple access (FDMA) divides it by frequency. An analogy to the problem of multiple access is a room (channel) in which people wish to communicate with each other. To avoid confusion, people could take turns speaking (time division), speak at different pitches (frequency division), or speak in different directions (spatial division). In CDMA, they would speak different languages. People speaking the same language can understand each other, but not other people. Similarly, in radio CDMA, each group of users is given a shared code. Many codes occupy the same channel, but only users associated with a particular code can understand each other. 35. explain different types of feedback? Types of feedback: Negative feedback: This tends to reduce output (but in amplifiers, stabilizes and linearizes operation). Negative feedback feeds part of a system's output, inverted, into the system's input; generally with the result that fluctuations are attenuated. Positive feedback: This tends to increase output. Positive feedback, sometimes referred to as "cumulative causation", is a feedback loop system in which the system responds to perturbation (A perturbation means a system, is an alteration of function, induced by external or internal mechanisms) in the same direction as the perturbation. In contrast, a system that responds to the perturbation in the opposite direction is called a negative feedback system. Bipolar feedback: which can either increase or decrease output. 36. What are the main divisions of power system? The generating system,transmission system,and distribution system. 37. What is Instrumentation Amplifier (IA) and what are all the advantages? An instrumentation amplifier is a differential op-amp circuit providing high input impedances with ease of gain adjustment by varying a single resistor. 38. What is meant by impedance diagram? The equivalent circuit of all the components of the power system are drawn and they are interconnected is called impedance diagram. 39. What is the need for load flow study? The load flow study of a power system is essential to decide the best operation existing system and for planning the future expansion of the system. It is also essential for designing the power system. 40. What is the need for base values? The components of power system may operate at different voltage and power levels. It will be convenient for analysis of power system if the voltage, power, current ratings of the components of the power system is expressed with referance to a common value called base value. 41.Why are the coupling capacitors required? To filter the Dc term from the Input signal , Collector output in amplifiers. 42.What is meant by thermal stabilization? Maintain a constant operating point when temperature varies 43.Explain why reversal of phase occurs in a BJT CE Amplifier. As Base voltage increases, base current increases, then collector current increases so voltage drop across Rc increases so out put voltage decreses. 44.What happens if an amplifier is biased at cutoff or at saturation? In cutoff region Ic is 0, in saturation region Vce is almost Zero. 45.What is the significance of the bandwidth of an amplifier? Bandwidth specifies the input signal frequency range that can be applied to amplifier to get maximum gain. 46.What is meant by Gain-Bandwidth Product? What is its significance? The name itself expressing it is the product of gain of a device and its bandwidth. For any system (circuit) gain bandwidth product is constant, if gain increases bandwidth decreases vice versa. 47.What are the advantages of using a FET instead of a BJT? FET has high input impedance, lower noise, low to medium gain, 48.What are the specifications of the SCR ? gate trigger voltage, gate trigger current, holding current, on-state voltage, peak gate power dissipation. 49.Can we interchange the source and drain terminals in a FET circuit? Can we do the same with the emitter and collector terminals of a BJT circuit? We can interchange drain and source but we cannot change emitter and collector because emitter and collectors dimensions and doping concentration is different 50.What is a MOSFET? How is it different from a JFET? What are its typical applications? Metal oxide semiconductor can be operated in both depletion and enhancement modes, but Junction field effect Transistor can be operated in depletion mode only. Read the full article

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    Specification

  ISDB system

Input Input Frequency：（Brazil：174~216MHz & 470~806MHz）（Japan：170MHz ~ 770MHz） input power：-95dBM~-0dBM input impedance：50ohm Demodulation modulation system：QPSK，16-QAM，64-QAM bandwidth：6MHz II decoding video decoding：MPEG4，AVC/H.264 Audio decoding standard:MPEG2，AAC Supported language Japan/ Portuguese/ Spanish/English LCD screen display RGB output analog video output(optional)

  Video output port (CVBS) output mode：Japan：NTSC；Brazil：PAL-M output impedance：75ohm Output level：1.0±20mVp-p（output format CVBS） Digital video output（optional） HDMI 1.4

Support format:

– 1920x1080p @ 60Hz

– 1920x1080i @ 30Hz

– 1280x720p @ 30Hz

– 720x480i @ 60Hz

– 720x480p @ 60Hz

audio output

  1 way 2W/8Ωloudspeaker；1way arphone USB interface Package Updated

，machine power supply interface（+5V DC），

Input power Car battery / Car lighter power consumption About 3.5W Working Temperature -20—75℃ size Length 143MM×wide 88M×thickness 23MM weight About 250G

Packaging details

    Product Name:

ISDB-T9

Carton size:

47*40*29(cm)

Unit Weight including package:

1.4 (kgs)

Quantity per carton:

10 (pcs)

Gross Weight per carton:

13.9 (kgs)

Single size:

27*20*10(cm)

full seg digital tv b-cas 2×2 tuner antenna

9 inch isdb-t full seg digital tv b-cas 2×2 tuner antenna

isdb-t full seg digital tv

ISDB-T9 9 inch isdb-t full seg digital tv b-cas 2×2 tuner antenna

  Gallery

    ISDB-T9 9 inch isdb-t full seg digital tv b-cas 2×2 tuner antenna with GPS / FM transmitter 9 inch isdb-t full seg digital tv b-cas 2x2 tuner antenna with GPS / FM transmitter…

[technato]

Overview of the LabVIEW Communications Application Frameworks

The insatiable demand for reliable and ubiquitous yet affordable wireless data connections for both people and machines is putting tremendous pressure on the wireless industry

Overview

The insatiable demand for reliable and ubiquitous yet affordable wireless data connections for both people and machines is putting tremendous pressure on the wireless industry. Industry consensus says that the next generation of wireless networks (5G) needs to improve capacity a thousand fold by 2020 without a commensurate increase in cost. To respond to this technological challenge, wireless researchers need to think outside the box and beyond the desktop simulation environment. They need to progress to the real-time prototyping of wireless systems to fully explore the innovations needed.

However, real-time wireless prototyping is an expensive, time-consuming task. Many factors need to be considered including the disparate skill sets required and the lack of a common hardware platform. But the most important challenge is a lack of viable starting points for the existing prevalent wireless standards such as LTE and 802.11 as well as new technologies such as massive multiple input, multiple output (MIMO).

The LTE, 802.11, and MIMO application frameworks provide ready-to-run, open, and modifiable real-time physical layer (PHY) and medium access control (MAC) layer reference designs. They are composed of modular baseband PHY and MAC blocks implemented using the LabVIEW Communications System Design Suite (LabVIEW Communications). The frameworks are designed to run on an FPGA and a general-purpose processor, which are tightly integrated with the RF and analog front ends of NI software defined radio (SDR) hardware.

These application frameworks provide a substantial starting point for researchers to find ways to improve and build prototyping systems. Some example research includes exploring brand-new algorithms and architectures that can support the tremendous increase of the number of terminals, inventing new waveforms by which to modulate and demodulate the signals, or finding new multi-antenna architectures that fully exploit the degrees of freedom in the wireless medium.

The frameworks are designed from the ground up for easy modifiability. This allows wireless researchers to quickly get their real-time prototype up and running based on the LTE and 802.11 standards as well as MIMO technology. They can then primarily focus on the selected aspects of the protocol that they wish to improve, easily modify the designs, and compare their innovations with existing standards.

The PHY and MAC blocks are documented in the product and presented in a graphical block diagram form using LabVIEW Communications. They have clearly defined interfaces, documented system performance benchmarks, and computational resource usage. Additionally, LabVIEW Communications is shipped with a video-streaming application that shows the transfer of real-time data over the air using these standards-compliant wireless links. 

Relevant parameters for the wireless links are easily adjustable from the software front panel generated with LabVIEW Communications. Furthermore, relevant link metrics, including received power spectrum, received constellation, throughput, and block error rates, are also displayed for easy assessment of the link quality. They allow researchers to understand the effects of various parameters on communications performance.

These application frameworks, combined with the ease of development LabVIEW Communications provides and the seamless integration with NI SDR hardware, enable wireless researchers to innovate faster and reduce time to market for their next breakthrough innovations.

1. LabVIEW Communications LTE Application Framework

The latest version of the LabVIEW Communications LTE Application Framework includes:

Subset of a 3GPP-LTE release 10 compliant physical layer

SISO configuration

Closed-loop over-the-air operation with channel state and ACK/ NACK feedback

20 MHz bandwidth

Physical Downlink Shared Channel (PDSCH) and Control Channel (PDCCH)

Up to 75 Mbps data throughput

Normal cyclic prefix mode

FDD and TDD configuration 5-frame structure

QPSK, 16-QAM, and 64-QAM modulation

Variable physical resource block (PRB) allocations

LTE-compliant data-channel coding

Cell-specific and UE-specific reference signals

Primary synchronization signal

Sounding reference signal (SRS)

Receiver algorithms

Automatic gain control

Synchronization based on PSS including time and frequency tracking

Channel estimation and zero-forcing channel equalization

Basic MAC to enable packet-based data transmission and MAC adaptation framework for rate adaptation

Hardware support for USRP RIO, stand-alone USRP-RIO, NI Linux Real-Time, PXIe-7975/7976 PXI FPGA Modules for FlexRIO, and NI-5791 RF Adapter Module for FlexRIO

L1/L2 API to interface with upper MAC

2. LabVIEW Communications 802.11 Application Framework

The latest version of the LabVIEW Communications 802.11 Application Framework includes:

Subset of an 802.11a/g/ac PHY layer

SISO transmission

20 MHz bandwidth legacy (802.11a)

20MHz/ 40MHz VHT modes up to MCS 9 (802.11ac)

80 MHz VHT mode up to MCS 4 (802.11ac)

BPSK, QPSK, 16-QAM, 64-QAM and 256-QAM modulation support

Convolutional encoding and Viterbi decoding

Receiver algorithms

Training field-based packet detection

Time and frequency synchronization, channel estimation and zero-forcing channel equalization

Signal field-based demodulation and decoding

Phase compensation

Lower MAC layer

MAC and PHY interface: PHY-SAP according to 802.11 standard

MPDU generation and recognition

Multinode addressing, CRC and frame type check, SIFS timing compliant (16µs) ACK generation

Clear channel assessment (CCA) information from PHY, processed by MAC

CSMA/CA procedure

Retransmission

RTS, CTS, and NAV support

L1/L2 API to interface with upper MAC

Hardware support for USRP RIO, stand-alone USRP-RIO, NI Linux Real-Time, PXIe-7975/7976 PXI FPGA Modules for FlexRIO, and NI-5791 RF Adapter Module for FlexRIO

3. LabVIEW Communications MIMO Application Framework

The latest version of the LabVIEW Communications MIMO Application Framework includes:

SU-MIMO, MU-MIMO, and Massive MIMO support

50 MHz – 6GHz frequency coverage

20 MHz bandwidth TDD UL and DL

Scalable number of base station antennas from 2 up to 128

Scalable number of mobile station antennas up to 12 antennas

Support for up to 12 spatial streams

Fully reconfigurable frame structure based on LTE

128×12 MMSE, ZF, MRC MIMO precoder/equalizer FPGA IP

4-QAM, 16-QAM, 64-QAM, and 256-QAM modulation support

Channel reciprocity calibration enabling reciprocity-based precoding 

AGC and open-loop power control

Over-the-air synchronization

Basic MAC functionality supports packet-based user data transmission in DL and UL to enable data-streaming applications such as video transmission

4. Modifying the Application Frameworks

Modifying the IP does require a deep understanding of the products. We offer a three-day in-class training course for LabVIEW Communications System Design Suite as well as a custom training for the application frameworks. If some level of the modification is required to fit your application needs, it is highly encouraged to take the training courses. Should you have any questions around the trainings, please contact your local sales representative.

5. Additional Resources

Buy LabVIEW Communications

Learn more about how LabVIEW can help you design a wireless communications system

Download the latest version of the LTE Application Framework manual

Download the latest version of the 802.11 Application Framework manual

Download the latest version of the MIMO Application Framework manual

The registered trademark Linux® is used pursuant to a sublicense from LMI, the exclusive licensee of Linus Torvalds, owner of the mark on a worldwide basis.

Overview of the LabVIEW Communications Application Frameworks syndicated from https://jiohowweb.blogspot.com

[stephenlibbyy]

What is the open packet optical switch, Voyager?

Modern web-scale data centers are thirsty for bandwidth. Popular applications such as video and virtual reality are increasing in demand, causing data centers to require higher and higher bandwidths — both within data centers and between data centers. In this blog post, we will briefly discuss the current challenges in the optics space as well as some of the key technical aspects of the Voyager’s DWDM transponders. In part two of this series, we will cover why Voyager is a unique, powerful and robust solution.

The challenges to accommodate longer distances

Within a data center, organizations are adding higher and higher bandwidth ports and connections to accommodate the need for more bandwidth. However, connections that accommodate longer distances between data centers may be limited and expensive. Therefore, a critical requirement for businesses with this challenge is how to support longer distance spans at higher bandwidths over a small amount of fiber pairs.

The optical industry solves the bandwidth problem using Dense Wave Division Multiplexing (DWDM). DWDM allows many separate connections on one fiber pair by sending them over different wavelengths. Although the wavelengths are sent on the same physical fiber, they act as “ships in the night” and don’t interact with each other, similar to VLANs on a trunk. Each wavelength can transport very high speeds (hundreds of Gigabits per second) over very long distances. While this is an incredible feat, today’s DWDM systems are typically closed and expensive. The transponders (which I’ll be explaining in more detail below) are generally the most expensive part of the closed DWDM network.

Announcing Voyager early access

Back in November, we announced the partnership between Cumulus and the open packet DWDM platform Facebook brought to the Telecom Infra Project (TIP), called Voyager, bringing the first open packet optical product to the industry. In just a few weeks, Voyager will officially be available for early access, and we’ll be rolling out a variety of resources for you to get to know the solution in more detail. Voyager is a Broadcom Tomahawk-based switch, similar to Facebook’s Wedge 100, but with added DWDM ports that can connect to another switch tens, hundreds or thousands of kilometers away by adding transponders.

By running Cumulus Linux, Voyager brings all the functionality of Cumulus with it, including BGP, EVPN, OSPF, Layer 2, native network automation and advanced monitoring — right to the optical world in just 1RU. We have also added typical DWDM transponder features, such as configuring power, wavelength, FEC, speed and performance monitoring. And of course, being Cumulus Linux, it’s extremely cost effective too. Finally, integrating L1/L2 and L3 all on Linux may enable you to reduce the number of nodes in the network and unify the entire data center from the hosts to the switches and even to the optical devices!

What is a DWDM transponder?

For reference, a typical active DWDM network is depicted below. Depending upon the use case, all elements below are not required for Voyager deployment. For example, Voyager can also be deployed over dark fiber with no ROADMs.

Voyager is the transponder (TPDR) in the below scenario and is also a Layer2/3 switch with all the functionality of a Broadcom Tomahawk switch with Cumulus Linux.

The transponder lives primarily at the edge of the DWDM network (with some exceptions, like when back-to-back transponders are used as a regenerator) and has a port to connect to a switch or router and a port to connect to the DWDM line system facing the remote end. In some cases, such as Voyager, the transponder could be located within a switch or router (i.e. the same box does switching, routing and transponding).

A muxponder is similar to a transponder, only it also performs time division multiplexing (TDM) over a pre-specified wavelength. For example, with a muxponder, you can send ten 10GigE links over a single 100G wavelength. Voyager will support this functionality as well.

What does a transponder do?

A transponder performs an optical-electrical-optical conversion and is primarily responsible for three tasks:

Converting the “grey” wavelength (850nm, 1310nm or 1550nm) to a pre-specified C-band wavelength and back

Encapsulating/decapsulating the ethernet frame into a layer 1 OTN or OTN-like frame and providing performance monitoring and forward error correction (FEC)

Modulating, transmitting, receiving, demodulating and controlling signal power

After the wavelength leaves the transponders line side port, it is typically multiplexed with other wavelengths and travels through the network over single mode fiber. Any wavelength could be dropped off or added at any site with a ROADM. At the remote end, the signal is de-multiplexed before being handed back to the transponder. The transponder provides performance monitoring, fixes any transmission errors and decapsulates the OTN frame before handing the ethernet frame back to a switch or router or an upper layer.

Voyager combines the transponder with L2/L3 — doing the “ethernet handoff” internally to Voyager itself.

What is a C-band wavelength?

The ITU-T divides the fiber optic communication spectrum (part of the infrared section of the full electromagnetic spectrum) into 6 bands: O, E, S, C, L and U. The attenuation across a single mode fiber optic cable is lowest (0.20-0.25dB/km) at the C-band (or conventional band), so it is primarily used for DWDM communications. Also, low cost Erbium Doped Fiber Amplifiers (EDFAs) help boost signals operating at this range. Voyager will support transmitting/receiving on the C-band.

The C-band wavelength spectrum used by Voyager is shown below:

The Voyager line port can be tuned to use a pre-specified C-band wavelength. It will support tuning at 50GHz spacing and flex spacing at 12.5GHz increments. The channels are fixed and determined at every 12.5GHz or 50GHz along the spectrum, identified by ITU-T G.694.1. With flex grid, they can be chosen by the operator at every 12.5GHz, with the operator being careful not to let the channels sidebands overlap. The sidebands can be different depending on the speed and modulation type of the channel.

What is an OTN or OTN-like frame?

An Optical Transport Network (OTN) frame (or the like) is used with DWDM. An ethernet frame is run inside it for this application.

It looks similar to the following:

As you can see, an OTN frame (which is in the electrical domain) consists of three overhead layers and they are analogous to SONET Line, Section and Path overheads:

Optical Transport Unit (OTU): Between optical network elements

Optical Data Unit (ODU): Network level

Optical Path Unit (OPU): Responsible for end-to-end

It also offers Forward Error Correction (FEC) and OAM&P (performance monitoring) capabilities within the overheads. Using amplifiers (specifically EDFAs) in a network can increase noise, thereby reducing signal quality and creating potential errors. FEC is used to correct the errors.

Several FEC algorithms exist in the industry today. Generally, the Soft Decision (SD) FECs can correct more errors than Hard Decision FECs, so the optical network can push longer distances at faster speeds with an SD-FEC. Voyager will run an SD-FEC.

Performance monitoring consists of reporting and keeping track of when there are errors in the network. For example, it keeps track of the pre-FEC bit error rate (BER), which is how many errors the FEC had to correct to be able to deliver a clean frame up to the higher layers. All of these characteristics can tell an operator if the network has issues, such as a degrading amplifier.

What is modulation and transmitting?

A transponder/muxponder is also responsible for modulating the signal and transmitting the signal at the appropriate power level. Transmitting at too little power won’t drive very far, and transmitting at too much power can distort the signal. Voyager will be able to effectively transmit up to +2.5dBm.

Different modulations are typically used with different bit rates. For example, lower bit rates at or below 10Gbps may use on-off keying (OOK). OOK is a simple modulation method that turns light on to signify a binary “1” and turns light off to signify a binary “0”. In this scenario, the bit rate and the symbol (baud) rate (signals through the fiber) are the same. Phase Shift Keying (PSK) uses the same idea, but instead of changing the power of the signal, it changes its phase to denote a binary “0” or “1”.

As we get to higher and higher bit rates, we want to keep the baud rate low to minimize distortions while increasing the bit rate we send. This leads to more complex modulation types, such as QPSK (Quadrature Phase Shift Keying) and 8 & 16 QAM (Quadrature Amplitude Modulation). QPSK transmits 2 bits per baud, 8 QAM transmits 3 bits per baud and 16 QAM transmits 4 bits per baud. Additionally, when we modulate 2 orthogonal polarizations separately (sometimes called Dual Polarization or Polarization Division Multiplexing), we double the throughput. Voyager will support QPSK with 100Gbps, 8QAM with 150Gbps, and 16QAM with 200Gbps with PDM.

As more and more bits per symbol are transmitted, more symbols are needed to represent the different bit patterns. The symbols are then represented closer together and thus more difficult to distinguish from each other. Therefore, the signal needs to be “cleaner” and have less noise in order to read it effectively. This leads to shorter supported distances and the need for more complex FEC algorithms, such as SD-FEC.

Of course, a transponder also receives and demodulates the signal on the remote end.

What now?

At this point, you hopefully understand the basic technical challenges and needs with DWDM. This blog post covered the technical aspects of a transponder within Voyager. In part two, we will cover the question “Why Voyager?” and discuss Voyager functionality and use cases in greater detail. We couldn’t be more excited to be releasing Voyager for early access in just a few weeks, along with several supporting resources. If you’re dying to check it out in more detail in the meantime, visit Adva’s website, as they will be supporting and selling the product with Cumulus Linux, or contact TIP. Stay Tuned for more!

The post What is the open packet optical switch, Voyager? appeared first on Cumulus Networks Blog.

What is the open packet optical switch, Voyager? published first on https://wdmsh.tumblr.com/

[soukacatv]

Analog and Digital Modulation Basic Introduction

Overview

This tutorial is part of the National Instruments Measurement Fundamentals series. Each tutorial in this series, will teach you a specific topic of common measurement applications, by explaining the theory and giving practical examples. This tutorial covers an introduction to analog and digital modulation.

For the complete list of tutorials, return to the NI Measurement Fundamentals Main page or for more RF tutorials refer to the NI RF Fundamentals Main subpage.

HDMI Encoder Modulator,16in1 Digital Headend, HD RF Modulator at SOUKA https://www.soukacatv.com/.

Table of Contents

1.     Modulation Basics

2.     Digital Modulation

3.     I and Q Data

4.     IQ vs. IF Modulators

5.     Relevant NI Hardware

6.     Conclusions

1. Modulation Basics

Modulation is a process in which a modulator changes some attribute of a higher frequency carrier signal proportional to a lower frequency message signal. If the carrier is represented by the equation

Figure 1. Carrier Signal Equation

a change in the message signal will produce a corresponding change in either the amplitude, frequency, or phase of the carrier. A transmitter can then send this carrier signal through the communication medium more efficiently than the message signal alone. Finally, a receiver will demodulate the signal, recovering the original message. In Amplitude Modulation (AM), pictured below, the amplitude of the carrier sinusoid changes based on the amplitude of the message.

Figure 2. Amplitude Modulation

The message signal (red) rides on top of the carrier as the amplitudes of both vary with time. The frequency of the carrier, however, is much higher than the frequency of the message. This carrier frequency is the center of the 'channel,' or frequency allocation of this RF signal. Frequency allocations vary depending on the medium of transmission. For broadcast transmissions, where signals are sent through the air, the government regulates frequency allocation. If the RF signal is transmitted over wire, such as in cable television, there is more freedom in the choice of carrier. In addition to amplitude modulation, frequency modulation varies the frequency of the carrier sinusoid based on the amplitude of the message signal. Similarly, phase modulation changes the phase of the carrier in response to a change in amplitude of the message.

2. Digital Modulation

Digital modulation is similar to analog modulation, but rather than being able to continuously change the amplitude, frequency, or phase of the carrier, there are only discrete values of these attributes that correspond to digital codes. There are several common digital modulation schemes, each varying separate sets of parameters. The simplest type is called On Off Keying (OOK) where the amplitude of the carrier corresponds to one of two digital states. A nonzero amplitude represents a digital one while a zero amplitude is a digital zero. A specific implementation of OOK is Morse Code. Frequency Shift Keying (FSK), seen in Figure 3, is a form of frequency modulation where a certain frequency represents each binary value.

Figure 3. Frequency Shift Keying (FSK)

Finally, Quadrature Amplitude Modulation (QAM) uses combinations of amplitudes and phases to represent more than 2 digital states, as many as 1024.

3. I and Q Data

Before comparing IQ and IF modulators, review the tutorial: "What is I/Q Data?".4. IQ vs. IF Modulators

After calculating digital I and Q data from the baseband message signal, there are two methods of converting this data into an analog RF signal. The first method involves converting I and Q data into analog signals, then feeding them into a quadrature encoder. There, they control the amplitudes of two oscillators, operating 90 degrees out of phase. The output of these oscillators is summed, resulting in an RF signal with the appropriate amplitude, phase, and frequency.

Figure 4. IQ Modulation

The next method of converting digital I and Q data to analog RF performs the oscillator scaling and summing in the digital domain. That is, digital sinusoids with a phase difference of 90 degrees are scaled by the digital I and Q values, then added together. These digital sinusoids are of a lower frequency than the analog oscillators in the IQ modulation scheme, but still at a significantly higher frequency than the message signal. A digital to analog converter (DAC), which operates at a much higher frequency than the DAC used in IQ modulation, converts the resulting digital waveform to low frequency analog RF. Finally, an analog IF to RF upconverter uses several stages of mixing and filtering to shift the analog RF signal to the desired RF frequency.

Figure 5. IF Modulation

·         The NI 5660 RF Vectors Signal Analyzer and the NI 5671 RF Vector Signal Generator use the IF modulation scheme depicted in Figure 5.

5. Relevant NI Hardware

Customers interested in this topic were also interested in the following NI products:

·         NI RF & Communications Platform

·         NI 5660 2.7 GHz RF Vector Signal Analyzer

·         NI 5671 2.7 GHz RF Vector Signal Generator

·         NI RF Switch Hardware

·         NI Modulation Toolkit Software

6. Conclusions

This document is meant to provide a brief introduction to analog and digital modulation.

For the complete list of tutorials, return to the NI Measurement Fundamentals Main page or for more RF tutorials refer to the NI RF Fundamentals Main subpage.

Established in 2000, the Soukacatv.com (DSW) main products are modulators both in digital and analog modulators, amplifier and combiner. We are the leading communication supplier in manufacturing the headend system in China. Our 16 in 1 and 24 in 1 now are the most popular products all over the world. For more, please access to https://www.soukacatv.com.

Source: http://www.ni.com/white-paper/3013/en/

[catvbroadcast-blog]

Digital television systems

source: freeimages.com

The specific problem with global digital tv is quite a bit simpler compared to. Most electronic television approaches have been based on the MPEG transport stream standard, and also use the H.262/MPEG-2 aspect 2 movie codec. They fluctuate considerably in the particulars of the way the transfer stream is converted to some broadcasting signal, in the movie format ahead of communicating (or alternatively( right after decoding), and from the sound format. That has not stopped the creation of an worldwide standard that contains both major processes, even though they have been oblivious in practically every respect. The two principal digital broadcasting approaches have been ATSC specifications, manufactured by the Advanced Television Systems Committee and adopted as a benchmark in most of the united states, also dvbt, the Digital Video Broadcast — Terrestrial technique used in most of the remaining part of earth. DVB-T was created for format compatibility with existing lead broadcast satellite providers at Europe (which utilize the dvbs conventional, and sees some use at direct-to-home satellite dish providers in North America), and there is also a DVB-C version for cable tv. While the ATSC standard also includes support for satellite and cable systemsand operators of those systems have chosen other technology (principally dvb s or proprietary systems such as satellite and 256QAM replacing VSB for cable). Japan employs an third platform, closely related to dvbt, termed ISDB-T, that is compatible with Brazil`s SBTVD. The People`s Republic of China has developed an fourth system, called DMB-T/H.

The brand new ATSC process (unofficially ATSC-T) uses a proprietary Zenith-developed modulation known as 8-VSB; as its name implies, it`s a vestigial sideband method. In essence, analog VSB is to regular amplitude modulation since 8VSB is always to eight-way quadrature amplitude modulation. The platform was chosen especially to give optimum spectral compatibility between active analog television and brand new digital stations inside the united states of america` already-crowded tv allocations system, though it`s poor to the other digital approaches in handling multi path interference; however, it really is better at dealing with impulse noise that`s especially present on the VHF bands which other countries have discontinued from television use, but are still used at the U.S.. After demodulation and error-correction, the 8-VSB modulation affirms an electronic digital data flow of about 19.39 Mbit/s, enough for you personally high-definition video flow or a few standard definition companies. Watch Digital subchannel: Technical considerations to learn more. On November 17, 20 17, the FCC voted 3-2 in favour of authorizing voluntary deployments of both ATSC 3.0, which was made as the successor to the initial ATSC “1.0”, also issued a Report and Order to that effect. Full-power stations will be required to keep a simulcast of their stations in an ATSC 1.0-compatible signal should they opt to employ an ATSC 3.0 assistance. On cable, ATSC commonly utilizes 256QAM, though some utilize 16VSB. Both double the throughput to 38.78 Mbit/s within the same 6 MHz bandwidth. ATSC is also used on satellite. While these are logically called ATSC-C and ATSC-S, these phrases have been never officially defined.

DTMB Could Be your electronic tv broadcasting standard of the People`s Republic of China, Hong Kong and Macau. This can be really a fusion system, which really is a compromise of unique competing indicating criteria from different Chinese Facultiesthat incorporates elements from DMB-T, ADTB-T and also TiMi 3.

Digital Video Broadcasting, DVB-T, Dvbs, along with DVB-C

This method was created to supply superior immunity out of multipath disturbance, also has a choice of platform versions that enable data levels from 4 MBit/s up to 24 MBit/s. One particular US broadcaster, Sinclair Broadcasting, petitioned the Federal Communications Commission to permit the use of COFDM as an alternative of 8-VSB, on the theory that could improve prospects for digital television reception by homes devoid of exterior antennas (most inside the US), yet this request was denied. (Yet, a single US digital station, WNYE-DT in newyork, was temporarily converted to COFDM modulation within an emergency foundation for datacasting advice to emergency services employees in lower Manhattan at the aftermath of the September 11 terrorist attacks). DVB-S is the initial electronic Video Broadcasting forwards mistake coding and modulation standard for satellite television and dates back to 1995. It`s employed by way of satellites operating just about every continent of the world, which includes North America. Dvb S is used in both MCPC and SCPC modes for broadcast community packs, Together with for direct broadcast satellite solutions like Sky and Freesat from the British Isles, Sky Deutschland and H D+ in Germany and Austria, TNT SAT/FRANSAT along with CanalSat in France, Dish Network in the Usa, along with Bell TV in Canada. The MPEG transport stream sent by DVB-S is known as mpeg 2. DVB-C means Digital Video Broadcasting – Cable plus it is that the DVB European consortium benchmark for the broadcast transmission of electronic tv. This technique transmits an mpeg 2 household digital jelqing stream, with a QAM modulation with station programming.

Source: freeimages.com (Keith Syvinski)

ISDB is extremely like DVB, however it`s divided up into 1 3 sub-channels. Collars are employed for TV, while the last functions either as a shield group, or to get your own 1 SEG (ISDB-H) assistance. Much like one different DTV systems, the ISDB types differ chiefly in the modulations used, due to the requirements of distinct frequency rings. The 1-2 GHz band ISDB-S uses PSK modulation, 2.6 GHz ring electronic sound broadcasting employs CDM and ISDB-T (in VHF and/or UHF ring) utilizes COFDM together with PSK/QAM. It was developed in Japan using MPEG-2, and is now Utilised in Brazil together with Mpeg4. Not like other digital broadcast systems, ISDB includes digital rights management to confine recording of programming.

Converting between diverse numbers of lines along with unique frequencies of fields/frames in video pictures is not an easy job. Perhaps the very technically hard conversion to make is from some one of those 625-line, 25-frame/s systems to platform M, and this includes 525-lines at 29.97 frames each minute. Historically that required a frame retail store to hold the sections of the picture perhaps not actually currently being output (because the scan of some point wasn`t moment coincident). In more recent instances, the transformation of requirements is really a relatively easy job for an individual computer. Aside from the line count differs, it is easy to realize that making 59.94 areas every moment out of a format that has only 50 subjects could present a few intriguing issues. Every moment, an extra 10 subjects must be made apparently out of nothing. The transformation has to develop new frames (from your present input) in real time. There are several techniques utilized to accomplish this, based on your desirable charge and conversion quality. The simplest possible converters simply shed every 5th lineup from every framework (when switching from 625 to 525) or duplicate every 4th line (when converting from 525 to 625), and after that duplicate or drop a few of those frames to form the difference in body speed. More elaborate systems consist of inter-field interpolation, flexible interpolation, and period correlation.

For more infotmation, please visit https://catvbroadcast.com/news/digital-television-systems/

[fuguitianxiae-blog]

Acterna JDSU SDA-4040D Digital QAM Pathtrk

Welcome to a Biomedical Battery specialist of the Acterna Battery

The SDA-4040D with battery like JDSU GPDR204 Battery, JDSU LI204SX Battery, JDSU MTS-6000 Battery, JDSU LI204SX-60A Battery, JDSU LI204SX-66A Battery, JDSU LI204SX-60 Battery, HP VA7100 Battery, HP VA7110 Battery, HP VA7400 Battery, HP VA7410 Battery, Biocare ECG-9803 Battery is used for HFC network testing and deployment of digital video, data, and traditional analog services. It is part of a system sweep solution. The SDA-4040D is a small, lightweight hand-held field CATV Sweep Analyzer for diagnosing and eliminating problems quickly in CATV system equipment. Ideal for aligning amplifiers, testing performance of forward path networks, measuring signal quality, and fulfilling FCC and CENELEC proof-of-performance requirements.

Highlights :

* Full, in-service, proof-of-performance analyzer. * Fast, sensitive spectrum analyzer. * New digital QAM measurement option for forward path carriers. * Digital QAM carrier demodulation includes 64, 128, and 256 QAM constellation display with zoom, average digital power level, bit error rate (BER), and 21 to 35 dB modulation error rate (MER).

Applications :

* Cable modem analysis using Zero Span mode provides accurate, in-service power and C/N measurements. * QAM View option provides complete analysis of digital TV and forward cable modem signals. * Find ingress fast with Field View option. Cable technicians working in the field can see the reverse path at the headend. * Graphical test point compensation makes it easier to add, edit, and store parameters.

Key Features :

* QAM View includes BER, MER, and constellation. * Equalizer stress and microreflections. * QAM ingress (noise-under-carrier). * PathTrak Field View option.

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Advantages and Disadvantages of ASK, FSK, PSK—BPSK, QPSK, MPSK | Soukacatv.com

ASK vs. FSK vs. PSK-Difference between ASK, FSK, PSK modulation

This page on ASK vs. FSK vs. PSK provides difference between ASK, FSK, PSK modulation types. All these are digital modulation techniques. Unlike Analog modulation, here input is in digital binary form. The other input is the RF carrier. Input binary data is referred as modulating signal and output is referred as modulated signal.

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ASK

The short form of Amplitude Shift Keying is referred as ASK. It is the digital modulation technique. In this technique, amplitude of the RF carrier is varied in accordance with baseband digital input signal. The figure depicts operation of ASK modulation. As shown in the figure, binary 1 will be represented by carrier signal with some amplitude while binary 0 will be represented by carrier of zero amplitude(i.e. no carrier).

Fig.1 ASK Modulation

ASK modulation can be represented by following equation:

s(t) = A2* cos(2*π*fc*t) for Binary Logic-1

s(t) = A1* cos(2*π*fc*t) for Binary Logic-0

Here A2>A1

Signaling used is ON-OFF signaling.

Bandwidth requirement for ASK is:

BW = 2/Tb = 2*Rb

Often in ASK modulation, binary-1 is represented by carrier with amplitude-A2 and binary-0 is represented by carrier with amplitude-A1. Here A2 is greater in magnitude compare to A1. The form of ASK where in no carrier is transmitted during the transmission of logic zero is known as OOK modulation (On Off Keying modulation). This is shown in the figure-1. Refer OOK vs ASK modulation >> which compares OOK vs. ASK and depicts difference between OOK and ASK modulation types with signal diagrams.

• In ASK probability of error (Pe) is high and SNR is less.

• It has lowest noise immunity against noise.

• ASK is a bandwidth efficient system but it has lower power efficiency.

FSK

The short form of Frequency Shift Keying is referred as FSK. It is also digital modulation technique. In this technique, frequency of the RF carrier is varied in accordance with baseband digital input. The figure depicts the FSK modulation. As shown, binary 1 and 0 is represented by two different carrier frequencies. Figure depicts that binary 1 is represented by high frequency 'f1' and binary 0 is represented by low frequency 'f2'.

Fig.2 FSK

Binary FSK can be represented by following equation:

s(t) = A* cos(2*π*f1*t) for Binary 1

s(t) = A* cos(2*π*f2*t) for Binary 0

In FSK modulation, NRZ signaling method is used. Bandwidth requirement in case of FSK is:

BW = 2*Rb + (f1-f2)

• In case of FSK, Pe is less and SNR is high.

• This technique is widely employed in modem design and development.

• It has increased immunity to noise but requires larger bandwidth compare to other modulation types.

In order to overcome drawbacks of BFSK (Two level Binary FSK) , multiple FSK modulation techniques with more than two frequencies have been developed. In MFSK (Multiple FSK), more than one bits are represented by each signal elements.

Refer 2FSK and 4FSK Modulation types.

PSK

The short form of Phase Shift Keying is referred as PSK. It is digital modulation technique where in phase of the RF carrier is changed based on digital input. Figure depicts Binary Phase Shift Keying modulation type of PSK. As shown in the figure, Binary 1 is represented by 180 degree phase of the carrier and binary 0 is represented by 0 degree phase of the RF carrier.

Fig.3 PSK

Binary PSK can be represented by following equation :

If s(t) = A*cos(2*π*fc*t) for Binary 1 than

s(t) = A*cos(2*π*fc*t + π) for Binary 0

In PSK modulation, NRZ signaling is used. Bandwidth requirement for PSK is:

BW = 2 * Rb = 2 * Bit rate

• In case of PSK probability of error is less. SNR is high.

• It is a power efficient system but it has lower bandwidth efficiency.

• PSK modulation is widely used in wireless transmission.

• The variants of basic PSK and ASK modulations are QAM, 16-QAM, 64-QAM and so on.

Advantages and Disadvantages of ASK, FSK and PSK

ASK Advantages | ASK Disadvantages | Amplitude Shift Keying

This page covers advantages and disadvantages of ASK.ASK stands for Amplitude Shift Keying. Both ASK advantages and ASK disadvantages are covered.

Following are the silent features of ASK modulation.

• ASK is digital modulation technique in which carrier is analog and data to be modulated is digital. Modulated output is analog.

• Here strength or amplitude of carrier signal is varied to represent binary 1 and binary 0 data inputs; While frequency and phase of the carrier signal remain constant. Voltage levels are left to designers of the modulation system.

Figure-1: ASK Modulation

ASK Advantages

Following points summarizes ASK advantages:

➨It offers high bandwidth efficiency.

➨It has simple receiver design.

➨ASK modulation can be used to transmit digital data over optical fiber.

➨ASK modulation and ASK demodulation processes are comparatively inexpensive.

➨Its variant OOK is used at radio frequencies to transmit more codes.

ASK Disadvantages

Following points summarizes ASK disadvantages:

➨It offers lower power efficiency.

➨ASK modulation is very susceptible to noise interference. This is due to the fact that noise affects the amplitude. Hence another alternative modulation technique such as BPSK which is less susceptible to error than ASK is used.

FSK Advantages | FSK Disadvantages | Frequency Shift Keying

This page covers advantages and disadvantages of FSK. It mentions FSK advantages or benefits and FSK disadvantages or drawbacks. FSK stands for Frequency Shift Keying.

What is FSK?

Introduction:

It is a digital modulation technique which shifts the frequency of the carrier with respect to binary data signal. FSK stands for Frequency Shift Keying. The FSK modulation technique uses two different carrier frequencies to represent binary 1 and binary 0.

As shown in the figure-1, carrier frequency f1 represents binary data one and carrier frequency f2 represents binary data zero. Here amplitude and phase of the carrier remain constant while carrier frequency is changed. Binary FSK (BFSK) can be represented by following mathematical equation:

s(t) = A* cos(2*π*f1*t) for Binary 1

s(t) = A* cos(2*π*f2*t) for Binary 0

In this equation, f2 and f2 are offset from carrier frequency (Fc) by equal but opposite amounts.

Following are the typical applications of FSK modulation.

• It is used on voice grade lines for data rates up to 1200 bps.

• It is used for high frequency radio transmission from 3 to 30 MHz.

• It is also used in coaxial cable based LAN (Local Area Network) at higher frequencies.

Benefits or advantages of FSK

Following are the benefits or advantages of FSK:

➨It has lower probability of error (Pe).

➨It provides high SNR (Signal to Noise Ratio).

➨It has higher immunity to noise due to constant envelope. Hence it is robust against variation in attenuation through channel.

➨FSK transmitter and FSK receiver implementations are simple for low data rate application.

Drawbacks or disadvantages of FSK

Following are the disadvantages of FSK:

➨It uses larger bandwidth compare to other modulation techniques such as ASK and PSK. Hence it is not bandwidth efficient.

➨The BER (Bit Error Rate) performance in AWGN channel is worse compare to PSK modulation.

In order to overcome drawbacks of BFSK, multiple FSK modulation techniques with more than two frequencies have been developed. In MFSK (Multiple FSK), more than one bits are represented by each signal elements.

PSK Advantages | PSK Disadvantages | Phase Shift Keying

This page covers advantages and disadvantages of PSK. It mentions PSK advantages or benefits and PSK disadvantages or drawbacks. PSK stands for Phase Shift Keying.

What is PSK?

Introduction:

It is a digital modulation technique which uses phase of the analog carrier to represent digital binary data. Phase of the carrier wave is changed according to the binary inputs (1 or 0). In two level PSK, difference of 180 phase shift is used between binary 1 and binary 0.

There are many different types of modulation techniques which utilizes this concept to transmit digital binary data. It include two level PSK (i.e. BPSK), Four level PSK (i.e. QPSK) etc. Some techniques employ both amplitude and phase variation to represent binary data such as 16-QAM, 64-QAM, 256-QAM etc. Two level PSK represents single bit by each signaling elements while four level PSK represents two bits by each signaling elements and so on. 8-PSK represents three bits by each signaling elements.

Following are the equations used to represent BPSK.

➨s(t) = A*cos(2*π*fc*t) for Binary 1 than

➨s(t) = A*cos(2*π*fc*t + π) for Binary 0

As mentioned there are many variants of PSK modulation. Each of these PSK types have different advantages and disadvantages. We will have a look at common advantages and disadvantages of PSK techniques.

Benefits or advantages of PSK

Following are the benefits or advantages of PSK:

➨It carries data over RF signal more efficiently compare to other modulation types. Hence it is more power efficient modulation technique compare to ASK and FSK.

➨It is less susceptible to errors compare to ASK modulation and occupies same bandwidth as ASK.

➨Higher data rate of transmission can be achieved using high level of PSK modulations such as QPSK (represents 2 bits per constellation), 16-QAM (represents 4 bits per constellation) etc.

Drawbacks or disadvantages of PSK

Following are the disadvantages of PSK:

➨It has lower bandwidth efficiency.

➨The binary data is decoded by estimation of phase states of the signal. These detection and recovery algorithms are very complex.

➨Multi-level PSK modulation schemes (QPSK, 16QAM etc.) are more sensitive to phase variations.

➨It is also one form of FSK and hence it also offers lower bandwidth efficiency compare to ASK modulation type.

Digital Phase Modulation: BPSK, QPSK, DQPSK

Digital phase modulation is a versatile and widely used method of wirelessly transferring digital

data.

In the previous page, we saw that we can use discrete variations in a carrier’s amplitude or frequency as a way of representing ones and zeros. It should come as no surprise that we can also represent digital data using phase; this technique is called phase shift keying (PSK).

Binary Phase Shift Keying

The most straightforward type of PSK is called binary phase shift keying (BPSK), where “binary” refers to the use of two phase offsets (one for logic high, one for logic low).

We can intuitively recognize that the system will be more robust if there is greater separation between these two phases—of course it would be difficult for a receiver to distinguish between a symbol with a phase offset of 90° and a symbol with a phase offset of 91°. We only have 360° of phase to work with, so the maximum difference between the logic-high and logic-low phases is 180°. But we know that shifting a sinusoid by 180° is the same as inverting it; thus, we can think of BPSK as simply inverting the carrier in response to one logic state and leaving it alone in response to the other logic state.

To take this a step further, we know that multiplying a sinusoid by negative one is the same as inverting it. This leads to the possibility of implementing BPSK using the following basic hardware configuration:

However, this scheme could easily result in high-slope transitions in the carrier waveform: if the transition between logic states occurs when the carrier is at its maximum value, the carrier voltage has to rapidly move to the minimum voltage.

High-slope events such as these are undesirable because they generate higher-frequency energy that could interfere with other RF signals. Also, amplifiers have limited ability to produce high-slope changes in output voltage.

If we refine the above implementation with two additional features, we can ensure smooth transitions between symbols. First, we need to ensure that the digital bit period is equal to one or more complete carrier cycles. Second, we need to synchronize the digital transitions with the carrier waveform. With these improvements, we could design the system such that the 180° phase change occurs when the carrier signal is at (or very near) the zero-crossing.

QPSK

BPSK transfers one bit per symbol, which is what we’re accustomed to so far. Everything we’ve discussed with regard to digital modulation has assumed that the carrier signal is modified according to whether a digital voltage is logic low or logic high, and the receiver constructs digital data by interpreting each symbol as either a 0 or a 1.

Before we discuss quadrature phase shift keying (QPSK), we need to introduce the following important concept: There is no reason why one symbol can transfer only one bit. It’s true that the world of digital electronics is built around circuitry in which the voltage is at one extreme or the other, such that the voltage always represents one digital bit. But RF is not digital; rather, we’re using analog waveforms to transfer digital data, and it is perfectly acceptable to design a system in which the analog waveforms are encoded and interpreted in a way that allows one symbol to represent two (or more) bits.

QPSK is a modulation scheme that allows one symbol to transfer two bits of data. There are four possible two-bit numbers (00, 01, 10, 11), and consequently we need four phase offsets. Again, we want maximum separation between the phase options, which in this case is 90°.

The advantage is higher data rate: if we maintain the same symbol period, we can double the rate at which data is moved from transmitter to receiver. The downside is system complexity. (You might think that QPSK is also significantly more susceptible to bit errors than BPSK, since there is less separation between the possible phase values. This is a reasonable assumption, but if you go through the math it turns out that the error probabilities are actually very similar.)

Variants

QPSK is, overall, an effective modulation scheme. But it can be improved.

Phase Jumps

Standard QPSK guarantees that high-slope symbol-to-symbol transitions will occur; because the phase jumps can be ±90°, we can’t use the approach described for the 180° phase jumps produced by BPSK modulation.

This problem can be mitigated by using one of two QPSK variants. Offset QPSK, which involves adding a delay to one of two digital data streams used in the modulation process, reduces the maximum phase jump to 90°. Another option is π/4-QPSK, which reduces the maximum phase jump to 135°. Offset QPSK is thus superior with respect to reducing phase discontinuities, but π/4-QPSK is advantageous because it is compatible with differential encoding (discussed in the next subsection).

Another way to deal with symbol-to-symbol discontinuities is to implement additional signal processing that creates smoother transitions between symbols. This approach is incorporated into a modulation scheme called minimum shift keying (MSK), and there is also an improvement on MSK known as Gaussian MSK.

Differential Encoding

Another difficulty is that demodulation with PSK waveforms is more difficult than with FSK waveforms. Frequency is “absolute” in the sense that frequency changes can always be interpreted by analyzing the signal variations with respect to time. Phase, however, is relative in the sense that it has no universal reference—the transmitter generates the phase variations with reference to a point in time, and the receiver might interpret the phase variations with reference to a separate point in time.

The practical manifestation of this is the following: If there are differences between the phase (or frequency) of the oscillators used for modulation and demodulation, PSK becomes unreliable. And we have to assume that there will be phase differences (unless the receiver incorporates carrier-recovery circuitry).

Differential QPSK (DQPSK) is a variant that is compatible with noncoherent receivers (i.e., receivers that don’t synchronize the demodulation oscillator with the modulation oscillator). Differential QPSK encodes data by producing a certain phase shift relative to the preceding symbol. By using the phase of the preceding symbol in this way, the demodulation circuitry analyzes the phase of a symbol using a reference that is common to the receiver and the transmitter.

Summary

•Binary phase shift keying is a straightforward modulation scheme that can transfer one bit per symbol.

•Quadrature phase shift keying is more complex but doubles the data rate (or achieves the same data rate with half the bandwidth).

•Offset QPSK, π/4-QPSK, and minimum shift keying are modulation schemes that mitigate the effects of high-slope symbol-to-symbol voltage changes.

•Differential QPSK uses the phase difference between adjacent symbols to avoid problems associated with a lack of phase synchronization between the transmitter and receiver.

Established in 2000, the Soukacatv.com main products are modulators both in analog and digital ones, amplifier and combiner. We are the very first one in manufacturing the headend system in China. Our 16 in 1 and 24 in 1 now are the most popular products all over the world.

For more, please access to https://www.soukacatv.com.

CONTACT US

Dingshengwei Electronics Co., Ltd

Company Address: Building A, the first industry park of Guanlong, Xili Town, Nanshan, Shenzhen, Guangdong, China

Tel: +86 0755 26909863

Fax: +86 0755 26984949

Phone: +86 13410066011

Email:ken@soukacatv.com

Skype: soukaken

Source: rfwireless-world and allaboutcircuits

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Modulating 5G -- 5G are Hybrids of QAM and OFDM Modulation Principles | Soukacatv.com

The IoT will make heavy use of fifth-generation mobile networks that use a yet-to-be-determined modulation scheme. Here are the major contenders.

Fifth-generation mobile networks, abbreviated 5G, will form the telecommunications standards for the internet of things. Planners say 5G will have a higher capacity than the current 4G equipment partly to support the device-to-device, ultra reliable, and massive machine communications expected to help define the IoT of the future. Among the goals of 5G: lower latency than 4G equipment and lower battery consumption, data rates of tens of megabits per second for tens of thousands of users, several hundreds of thousands of simultaneous connections available for wireless sensors, along with better spectral signaling efficiency.

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The better spectral efficiency will partly be a function of the modulation schemes used in 5G. However, those modulation schemes have yet to be standardized. There are several contenders, and derivatives of the same quadrature-style schemes in use by mobile networks today haven’t been ruled out for 5G. So it is interesting to review the major modulation techniques now up for consideration as part of 5G.

Techniques discussed for 5G tend to use multiple carriers as a means of obtaining spectral efficiency. At present, 4G LTE uses QAM (quadrature amplitude modulation) with OFDM (orthogonal frequency division multiplexing) as modulation and OFDMA (OFDM multiple access) as access scheme. 5G will provide a high bit rate so it will need to make efficient use of the spectrum. Several of the ideas proposed for 5G are hybrids of QAM and OFDM principles.

Firstly, Quadrature techniques represent a transmitted symbol as a complex number and modulate a cosine and sine carrier signal with the real and imaginary parts. This lets the symbol be sent with two carriers. The two carriers are generally referred to as quadrature carriers. A coherent detector can independently demodulate these carriers. This principle of using two independently modulated carriers is the foundation of quadrature modulation.

Quadrature amplitude modulation conveys two analog message signals, or two digital bit streams, by changing (modulating) the amplitudes of two carrier waves, using the amplitude-shift keying (ASK) digital modulation scheme o+r amplitude modulation (AM) analog modulation scheme. The two carrier waves of the same frequency are out of phase with each other by 90° and are thus called quadrature carriers. The modulated waves are summed, and the final waveform is a combination of both phase-shift keying (PSK) and amplitude-shift keying (ASK), or, in the analog case, of phase modulation (PM) and amplitude modulation.

QAM conveys information by modulating the amplitudes of the two carrier waves, using either amplitude-shift keying (ASK) for digital data or straight amplitude modulation for analog. The two carrier waves of the same frequency, usually sinusoids, are out of phase with each other by 90°. The modulated waves are summed, and the final waveform is a combination of both phase-shift keying (PSK) and amplitude-shift keying (ASK).

QAM is said to be spectrally efficient, and the reason becomes clear by comparing a QAM signal with that of an ordinary AM’ed carrier. A straight amplitude-modulated signal has two sidebands. The carrier plus the sidebands occupy twice the bandwidth of the modulating signal. In contrast, QAM places two independent double-sideband suppressed-carrier signals in the same spectrum as one ordinary double-sideband suppressed-carrier signal.

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QAM can give arbitrarily high spectral efficiencies by setting a suitable constellation size. As a quick review, a constellation diagram represents the signal as a scatter diagram in the Q and I axes and represents the possible symbols as points on the plane. The more symbols defined in the modulation scheme, the more points on the constellation diagram. The number of points at which the signal can rest, i.e. the number of symbols, is indicated in the modulation format description: 16QAM uses a 16-point constellation, and so forth.

Constellation points are normally arranged in a square grid with equal vertical and horizontal spacing. Use of higher-order modulation formats, i.e. more points on the constellation, makes it possible to transmit more bits per symbol. However, use of higher-order symbols positions constellation points closer together, making the link more susceptible to noise. Specifically, it takes less noise to move the signal to a different decision point on the constellation diagram.

A point to note about QAM is that it is considered a single-carrier system. The two digital bit streams come from one source that is split into two independent signals.

QAM signals are often sent via multi-carrier modulation schemes that transmit one QAM signal over one of several subcarriers. The point of doing this is to simplify the task of compensating for distortions arising in the communication channel. Each of the subcarriers has a small bandwidth. The communication channel has a relatively flat frequency response over each of these small bands. So it is relatively easy to compensate for distortions over each of the small subcarrier bands.

In OFDM, many closely spaced orthogonal sub-carriers carry data on several parallel data streams or channels. Each sub-carrier is modulated with a conventional modulation scheme such as QAM at a low symbol rate, maintaining total data rates similar to conventional single-carrier modulation schemes in the same bandwidth.

The primary advantage of OFDM over using a single carrier is its ability to cope with severe interference as caused by RF sources at nearly the same frequency or frequency-selective fading from multipath. OFDM may be viewed as using many slowly modulated narrowband signals rather than one rapidly modulated wideband signal. The low symbol rate makes the use of a guard interval between symbols affordable, making it possible to eliminate inter-symbol interference (ISI) and use echoes and time-spreading to improve signal-to-noise.

The orthogonality of OFDM comes from the selection of the sub-carrier frequencies so they are orthogonal to each other. This basically means the spectrum space between sub-carriers obeys a mathematical relationship where it is inversely proportional to the symbol duration. Sub-carriers spaced this way don’t experience any cross-talk and thus eliminate the need for inter-carrier guard bands, simplifying the design of both the transmitter and the receiver.

There are a few inherent difficulties with OFDM. One is that an OFDM signal can have a high instantaneous peak compared to its average level. There can also be a large signal amplitude swing when the signal traverses from a low to a high instantaneous power. The power amp used must be linear over a wide bandwidth to prevent a high out-of-band harmonic distortion. This phenomenon can potentially interfere with adjacent channels.

Other difficulties arise with the time and frequency synchronization between the OFDM transmitter and receiver. Numerous techniques have been proposed for estimating and correcting both timing and carrier frequency offsets at the OFDM receiver. For example, one idea is to embed pilot tones into OFDM symbols, then use timing and frequency acquisition algorithms to sync on them.

HYBRID SCHEMES FOR 5G

Several of the modulation schemes under review for 5G are hybrids employing elements found in QAM and OFDM. One is called F-QAM or FSK-QAM. F-QAM is a combination of QAM and frequency shift keying (FSK). It has been proposed in conjunction with OFDMA, the multi-user version of OFDM where individual users are assigned subsets of subcarriers.

F-QAM combines MF-FSK (multiple frequency FSK) and MQ-QAM (multiple QAM modulation levels). F-QAM has many similarities with OFDM-IM (OFDM with index modulation). In both cases the information is not only conveyed through the modulated symbols but also via the indices of the active subcarriers. At the receiver side, the detection process is similar to that of the OFDM-IM. The receiver employs what’s called a log-likelihood-ratio (LLR) detector to determine the active subcarrier in each sub-block and, afterwards, estimates the received symbols using a maximum likelihood (ML) detector.

One drawback of current OFDMA schemes is that they require accurate synchronization of the user signals at the base station. Such synchronization is not straightforward and demands a lot of resources. So a lot of the work on 5G aims at a way around this base station syncing. One idea from AlcatelLucent Bell Labs is a modified OFDM waveform dubbed universal filtered multicarrier (UFMC). UFMC passes each bundle of adjacent subcarriers that belong to a user through a filter to minimize multi-user interference. Bandwidth efficiency is kept at the same level as OFDM, but UFMC uses no cyclic prefix (CP). The interval the CP normally occupies instead absorbs the transient of the underlying filters, making the filtering more effective.

Generalized frequency division multiplexing (GFDM) is another candidate waveform. GFDM may be thought of as a modified OFDM, where each subcarrier is shaped by a high-quality filter. To allow the addition of the CP, the subcarrier filtering operation in GFDM is based on a circular convolution.

Another 5G contender is based on filter bank multicarrier with offset QAM (FBMC-OQAM). FBMCs employ two sets of band pass filters called analysis and synthesis filters, one at the transmitter and the other at the receiver, to filter the collection of subcarriers being transmitted simultaneously in parallel frequencies. FBMC filter bandwidth, and therefore selectivity, is a parameter that can be varied during design. FBMC also offers better bandwidth efficiency when compared to OFDM. FBMC eliminates the need for CP processing while efficiently attenuating interferences within and close to the frequency band. FBMC systems are also comparatively more resistant to narrowband noise.

OTHER IDEAS

Though multi-carrier systems seem to be getting most of the attention for 5G, experts say single-carrier modulation could still be part of the spec. There is also what might be termed odd-ball techniques still in the mix. One is called faster than Nyquist (FTN) modulation. It is a non-orthogonal subcarrier system that actually makes use of intersymbol interference to pack more data into a communication channel.

Another non-orthogonal idea is called time-frequency packing. The carriers are close together, and a super-sophisticated detector in the receiver decodes the closely packed signals. TFS is implemented either with QAM or OQAM.

Finally, a couple of ideas from independent companies have been floated as 5G specs. One is called wave modulation (WAM) which comes from MagnaCom, an Israeli startup acquired by Broadcom. Here a set of algorithms implement a form of spectral compression. Details about WAM are sparse, but the spectral compression is said to enable a higher signaling rate thereby affording the use of lower-order symbol alphabet, which reduces complexity. It is also said to give an overall 10% system gain advantage, up to 4x increase in range, a 50% spectrum savings, improved noise tolerance, and increase in data speed.

Another company called Cohere Technologies patented a modulation technology called Orthogonal Time Frequency and Space (OTFS). Again, details about OTFS are sparse, but press releases put out by Cohere speak highly of it.

Established in 2000, the Soukacatv.com main products are modulators both in analog and digital ones, amplifier and combiner. We are the very first one in manufacturing the headend system in China. Our 16 in 1 and 24 in 1 now are the most popular products all over the world.

For more, please access to https://www.soukacatv.com.

CONTACT US

Dingshengwei Electronics Co., Ltd

Company Address: Building A, the first industry park of Guanlong, Xili Town, Nanshan, Shenzhen, Guangdong, China

Tel: +86 0755 26909863

Fax: +86 0755 26984949

Phone: +86 13410066011

Email:ken@soukacatv.com

Skype: soukaken

Source: microcontrollertips

[soukacatv]

The IoT will make heavy use of fifth-generation mobile networks that use a yet-to-be-determined modulation scheme. Here are the major contenders.

Fifth-generation mobile networks, abbreviated 5G, will form the telecommunications standards for the internet of things. Planners say 5G will have a higher capacity than the current 4G equipment partly to support the device-to-device, ultra reliable, and massive machine communications expected to help define the IoT of the future. Among the goals of 5G: lower latency than 4G equipment and lower battery consumption, data rates of tens of megabits per second for tens of thousands of users, several hundreds of thousands of simultaneous connections available for wireless sensors, along with better spectral signaling efficiency.

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The better spectral efficiency will partly be a function of the modulation schemes used in 5G. However, those modulation schemes have yet to be standardized. There are several contenders, and derivatives of the same quadrature-style schemes in use by mobile networks today haven’t been ruled out for 5G. So it is interesting to review the major modulation techniques now up for consideration as part of 5G.

Techniques discussed for 5G tend to use multiple carriers as a means of obtaining spectral efficiency. At present, 4G LTE uses QAM (quadrature amplitude modulation) with OFDM (orthogonal frequency division multiplexing) as modulation and OFDMA (OFDM multiple access) as access scheme. 5G will provide a high bit rate so it will need to make efficient use of the spectrum. Several of the ideas proposed for 5G are hybrids of QAM and OFDM principles.

Firstly, Quadrature techniques represent a transmitted symbol as a complex number and modulate a cosine and sine carrier signal with the real and imaginary parts. This lets the symbol be sent with two carriers. The two carriers are generally referred to as quadrature carriers. A coherent detector can independently demodulate these carriers. This principle of using two independently modulated carriers is the foundation of quadrature modulation.

Quadrature amplitude modulation conveys two analog message signals, or two digital bit streams, by changing (modulating) the amplitudes of two carrier waves, using the amplitude-shift keying (ASK) digital modulation scheme o+r amplitude modulation (AM) analog modulation scheme. The two carrier waves of the same frequency are out of phase with each other by 90° and are thus called quadrature carriers. The modulated waves are summed, and the final waveform is a combination of both phase-shift keying (PSK) and amplitude-shift keying (ASK), or, in the analog case, of phase modulation (PM) and amplitude modulation.

QAM conveys information by modulating the amplitudes of the two carrier waves, using either amplitude-shift keying (ASK) for digital data or straight amplitude modulation for analog. The two carrier waves of the same frequency, usually sinusoids, are out of phase with each other by 90°. The modulated waves are summed, and the final waveform is a combination of both phase-shift keying (PSK) and amplitude-shift keying (ASK).

QAM is said to be spectrally efficient, and the reason becomes clear by comparing a QAM signal with that of an ordinary AM’ed carrier. A straight amplitude-modulated signal has two sidebands. The carrier plus the sidebands occupy twice the bandwidth of the modulating signal. In contrast, QAM places two independent double-sideband suppressed-carrier signals in the same spectrum as one ordinary double-sideband suppressed-carrier signal.

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QAM can give arbitrarily high spectral efficiencies by setting a suitable constellation size. As a quick review, a constellation diagram represents the signal as a scatter diagram in the Q and I axes and represents the possible symbols as points on the plane. The more symbols defined in the modulation scheme, the more points on the constellation diagram. The number of points at which the signal can rest, i.e. the number of symbols, is indicated in the modulation format description: 16QAM uses a 16-point constellation, and so forth.

Constellation points are normally arranged in a square grid with equal vertical and horizontal spacing. Use of higher-order modulation formats, i.e. more points on the constellation, makes it possible to transmit more bits per symbol. However, use of higher-order symbols positions constellation points closer together, making the link more susceptible to noise. Specifically, it takes less noise to move the signal to a different decision point on the constellation diagram.

A point to note about QAM is that it is considered a single-carrier system. The two digital bit streams come from one source that is split into two independent signals.

QAM signals are often sent via multi-carrier modulation schemes that transmit one QAM signal over one of several subcarriers. The point of doing this is to simplify the task of compensating for distortions arising in the communication channel. Each of the subcarriers has a small bandwidth. The communication channel has a relatively flat frequency response over each of these small bands. So it is relatively easy to compensate for distortions over each of the small subcarrier bands.

In OFDM, many closely spaced orthogonal sub-carriers carry data on several parallel data streams or channels. Each sub-carrier is modulated with a conventional modulation scheme such as QAM at a low symbol rate, maintaining total data rates similar to conventional single-carrier modulation schemes in the same bandwidth.

The primary advantage of OFDM over using a single carrier is its ability to cope with severe interference as caused by RF sources at nearly the same frequency or frequency-selective fading from multipath. OFDM may be viewed as using many slowly modulated narrowband signals rather than one rapidly modulated wideband signal. The low symbol rate makes the use of a guard interval between symbols affordable, making it possible to eliminate inter-symbol interference (ISI) and use echoes and time-spreading to improve signal-to-noise.

The orthogonality of OFDM comes from the selection of the sub-carrier frequencies so they are orthogonal to each other. This basically means the spectrum space between sub-carriers obeys a mathematical relationship where it is inversely proportional to the symbol duration. Sub-carriers spaced this way don’t experience any cross-talk and thus eliminate the need for inter-carrier guard bands, simplifying the design of both the transmitter and the receiver.

There are a few inherent difficulties with OFDM. One is that an OFDM signal can have a high instantaneous peak compared to its average level. There can also be a large signal amplitude swing when the signal traverses from a low to a high instantaneous power. The power amp used must be linear over a wide bandwidth to prevent a high out-of-band harmonic distortion. This phenomenon can potentially interfere with adjacent channels.

Other difficulties arise with the time and frequency synchronization between the OFDM transmitter and receiver. Numerous techniques have been proposed for estimating and correcting both timing and carrier frequency offsets at the OFDM receiver. For example, one idea is to embed pilot tones into OFDM symbols, then use timing and frequency acquisition algorithms to sync on them.

HYBRID SCHEMES FOR 5G

Several of the modulation schemes under review for 5G are hybrids employing elements found in QAM and OFDM. One is called F-QAM or FSK-QAM. F-QAM is a combination of QAM and frequency shift keying (FSK). It has been proposed in conjunction with OFDMA, the multi-user version of OFDM where individual users are assigned subsets of subcarriers.

F-QAM combines MF-FSK (multiple frequency FSK) and MQ-QAM (multiple QAM modulation levels). F-QAM has many similarities with OFDM-IM (OFDM with index modulation). In both cases the information is not only conveyed through the modulated symbols but also via the indices of the active subcarriers. At the receiver side, the detection process is similar to that of the OFDM-IM. The receiver employs what’s called a log-likelihood-ratio (LLR) detector to determine the active subcarrier in each sub-block and, afterwards, estimates the received symbols using a maximum likelihood (ML) detector.

One drawback of current OFDMA schemes is that they require accurate synchronization of the user signals at the base station. Such synchronization is not straightforward and demands a lot of resources. So a lot of the work on 5G aims at a way around this base station syncing. One idea from AlcatelLucent Bell Labs is a modified OFDM waveform dubbed universal filtered multicarrier (UFMC). UFMC passes each bundle of adjacent subcarriers that belong to a user through a filter to minimize multi-user interference. Bandwidth efficiency is kept at the same level as OFDM, but UFMC uses no cyclic prefix (CP). The interval the CP normally occupies instead absorbs the transient of the underlying filters, making the filtering more effective.

Generalized frequency division multiplexing (GFDM) is another candidate waveform. GFDM may be thought of as a modified OFDM, where each subcarrier is shaped by a high-quality filter. To allow the addition of the CP, the subcarrier filtering operation in GFDM is based on a circular convolution.

Another 5G contender is based on filter bank multicarrier with offset QAM (FBMC-OQAM). FBMCs employ two sets of band pass filters called analysis and synthesis filters, one at the transmitter and the other at the receiver, to filter the collection of subcarriers being transmitted simultaneously in parallel frequencies. FBMC filter bandwidth, and therefore selectivity, is a parameter that can be varied during design. FBMC also offers better bandwidth efficiency when compared to OFDM. FBMC eliminates the need for CP processing while efficiently attenuating interferences within and close to the frequency band. FBMC systems are also comparatively more resistant to narrowband noise.

OTHER IDEAS

Though multi-carrier systems seem to be getting most of the attention for 5G, experts say single-carrier modulation could still be part of the spec. There is also what might be termed odd-ball techniques still in the mix. One is called faster than Nyquist (FTN) modulation. It is a non-orthogonal subcarrier system that actually makes use of intersymbol interference to pack more data into a communication channel.

Another non-orthogonal idea is called time-frequency packing. The carriers are close together, and a super-sophisticated detector in the receiver decodes the closely packed signals. TFS is implemented either with QAM or OQAM.

Finally, a couple of ideas from independent companies have been floated as 5G specs. One is called wave modulation (WAM) which comes from MagnaCom, an Israeli startup acquired by Broadcom. Here a set of algorithms implement a form of spectral compression. Details about WAM are sparse, but the spectral compression is said to enable a higher signaling rate thereby affording the use of lower-order symbol alphabet, which reduces complexity. It is also said to give an overall 10% system gain advantage, up to 4x increase in range, a 50% spectrum savings, improved noise tolerance, and increase in data speed.

Another company called Cohere Technologies patented a modulation technology called Orthogonal Time Frequency and Space (OTFS). Again, details about OTFS are sparse, but press releases put out by Cohere speak highly of it.

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Source: microcontrollertips

                          Modulating 5G — 5G are Hybrids of QAM and OFDM Modulation Principles | Soukacatv.com The IoT will make heavy use of fifth-generation mobile networks that use a yet-to-be-determined modulation scheme. Here are the major contenders.