#allaboutcircuits

[lieselotte-sky]

Rozmohl se nám tady takový nešvar

To, že se člověk nemá registrovat na LinkedIn, protože potom se z množství spamu zblázní, to je známá věc a patrně to nikdo příčetný neudělá. Tedy s pracovní adresou, že, na tohle máme adresy pro spam…když už je nevyhnutné se na něco takového registrovat. Problém je, že mi v poslední době to stejné udělali na allaboutcircuits či/a microwaves101, kde bych tohle úplně nečekala. Jistě, dávám tam souhlas s tím, že budu dostávat jejich bulletiny a s tím, že mě občas osloví s nabídkou nějaká firma, ale s tímhletím problém v zásadě nemám, od toho ty stránky ostatně jsou. Potíž je v tom, že aby tohle fungovalo, musí se předávat kontakty rozumným lidem, přesněji řečeno, kontakty by se neměly předávat vůbec, mělo by se spíše zajistit přeposlání, protože jinak to jaxi není pod kontrolou. Bohužel se tohle úplně nepovedlo, neb kupříkladu takový Virtek je otravný asi jako bonprix, Ulla Popken a Magnet3ptáken dohromady, navíc to chodí z různých adres včetně privátních.

Čímž se dostávám k dalšímu nešvaru — přetahování agresivního marketingu ze spotřebky do profesionální sféry. Tohle zase předvádí myšovač a působí to poněkud úsměvně. Začalo to někdy v zimě. Vyhrajte v nějaké šílené hře a získáte zdarma kleště (nebo co). Boha krista! Většině lidí ty kleště prostě zaplatí zaměstnavatel, my ostatní si to prostě dáme do nákladů a jednoduše se o to hrkne zákazník, při jehož zakázce to bylo zrovna potřeba. Podstatné je, že nikdo z nás to neplatí, takže to, že je to zdarma, se slevou, či tak, nás absolutně netankuje. Ovšem pokud do toho půjdu, tak namísto toho, abych měla čas pro sebe, budu honit nějaký nesmysl po obrazovce. A ten čas, ten už se mě dotýká osobně.

Druhý útok už ovšem poněkud zavání — morbidní aplikace. Jasně, představte si to. Sedím doma v pohovce a koukám na televizi…ne, to se nestane, ale „spotřební“ společnost to tak dělá…já budu tak maximálně poslouchat nějakou music. A teď se mi notifikací připomene myšovač, tak si tam z rozmaru koupím pár tranzistorů a nějaké rychlé operační zesilovače… Ježišmarjá! co je tohle za pitomost? To, co tam nakupuju, je dané tím, co navrhuji a to člověk jaxi dělá v práci a u komplu!! Takže morbidní aplikace je mi na co? Na dvě věci! A pokud ta parta bláznů začne následně oklešťovat web a já tu sračku budu muset někam instalovat, bude mě to buď zdržovat, nebo to holt poběží v emulátoru na komplu. V obou případech to ale znamená, že „musím něco řešit“ a tu věc mohu snadno vyřešit i změnou dodavatele, který mě nebude vysírat morbidními aplikacemi.

Takovýto marketing je zadarmo drahý. Ti lidé by si měli uvědomit, že na konci není nějaká ubohá důchodkyně, které když příjde 10× za den e-mail že si má koupit nějaké hadry, tak si je koupí u vize toho, že pak snad konečně bude klid (nebude). Tito mají na druhé straně lidi, kteří jsou schopni efektivně a rychle řešit problémy do té míry komplexní, že by se rozsahem nevešly do hlav ani deseti markeťáků, takže v momentě, kdy to začne být řekněme dostatečně otravné na to, aby to člověk začal řešit, tak to i vyřeší. A ta nejsnadnější řešení vedou směrem, který definitivně nevede k zvýšení prodejů na straně zadavatele. Já nemám nějaké přehnané představy o inteligenci markeťáka, ale to, že prodávat součástky vývojářům asi bude něco jiného než prodávat hadry z oddělení mladé módy, by snad pochopit mohl.

[electronitia]

The DHT11 is a commonly used Temperature and humidity sensor. The sensor comes with a dedicated NTC to measure temperature and an 8-bit microcontroller to output the values of temperature and humidity as serial data. The sensor is also factory calibrated and hence easy to interface with other microcontrollers. The sensor can measure temperature from 0°C to 50°C and humidity from 20% to 90% with an accuracy of ±1°C and ±1%. ____________________________ @electronitia || LIKE SHARE FOLLOW || . . . . #electronics #diys #temperature #arduinouno #iotproject #facts #mondaymotivation #crazystuff #electronicslove #allaboutcircuits #engineering_life #projectsfordays #pcbuilding #like4likes #follow4like #techworld #instadaily #techupdates https://www.instagram.com/p/CC3F4KegdT0/?igshid=1w8ly0vdyjrex

[realtalk-princeton]

@ECE Hardware technical interview: for my job they asked mostly circuits questions on the level of ECE203 (RC, LR, LRC circuits). Knowing some basic things about active components like MOSFETs, BJTs, and opamps, would also be useful but ultimately they’re probably looking for basic KVL, KCL problem solving ability. Not sure about digital but I image some basic logic circuits would be useful. allaboutcircuits is a good resource

thx!

[flaviosza]

Tweeted

"Introduction to Codes and Standards for Instrumentation and Controls Engineers" https://t.co/bHECL1FT0e via @allaboutcircuit

— ➟ Flávio Souza (@flaviosouza) April 5, 2020

[circuitme]

And the winner is...

Look what I won. A few weeks ago I attended a questionnaire at Dialog Semiconductor partner page, I believe it was AllAboutCircuits but I am not sure. It is some time ago and the time goes by very quickly. Nevermind. I won the development kit with a new and smaller BLE controller device. I briefly checked the datasheet and the Tiny device is really small with about 17 ports and it was naturally designed for very cost and space-sensitive applications. == Vyhrál jsem kitík od Dialog Semiconductor.

[sportsandplaysurfacetesting]

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[soukacatv]

The Many Types of Radio Frequency Modulation | Soukacatv.com

RF communication is built upon a simple concept: by continually altering the characteristics of a sinusoid, we can use it to transfer information.

At this point, we have covered a variety of important concepts that serve as a foundation for the successful design and analysis of real-world RF circuits and systems. We are now ready to explore a fundamental aspect of RF engineering: modulation.

HDMI Encoder Modulator,16in1 Digital Headend, HD RF Modulator at Soukacatv.com

SKD3013 3 Channel HD Encode Modulator

SKD19 Series 1U Rack 12CH Encode Modulator

What Is Modulation?

The general meaning of the verb “to modulate” is “to modify, to regulate, to vary,” and this captures the essence of modulation even in the specialized context of wireless communication. To modulate a signal is simply to intentionally modify it, but of course, this modification is done in a very specific way because the goal of modulation is data transfer.

We want to transfer information—ones, and zeros if we’re dealing with digital data, or a sequence of continuously varying values if we are working in the analog realm. But the restrictions imposed by wireless communication do not allow us to express this information in the typical way; instead, we have to devise a new “language,” or you might think of it as a code, that allows us to convey the same information but within the constraints of an electromagnetic-radiation-based system. More specifically, we need a language that is compatible with high-frequency sinusoidal signals, because such signals constitute the only practical means of “carrying” information in a typical RF system.

This high-frequency sinusoid that is used to carry information is called, appropriately, the carrier. It’s a helpful name because it reminds us that the purpose of an RF system is not to generate and transmit a high-frequency sinusoid. Rather, the purpose is to transfer (lower-frequency) information, and the carrier is simply the means that we must use to move this information from an RF transmitter to an RF receiver.

SKD121X Encoding & Multiplexing Modulator

Household Universal Encoding & Modulation Modulator

Modulation Schemes

In verbal communication, the human body generates sound waves and modifies—or modulates—them so as to produce a wide variety of vowels and consonants. Intelligent use of these vowels and consonants results in the transfer of information from the speaker to the listener. The system according to which the sound waves are modulated is called a language.

In RF communication, the situation is very similar. A device modulates electrical waves according to a predefined system called a modulation scheme (or modulation technique). Just as there are many human languages, there are many ways in which a carrier can be modulated.

It is possible that certain human languages are especially effective in conveying certain types of information; to take an example from the ancient world, perhaps Greek was better for philosophy and Latin was better for codifying laws. There is no doubt, however, that reliable communication is possible with any properly developed language, as long as the speaker and the listener both know it. The same is true for RF systems. Each modulation scheme has its advantages and disadvantages, but all can provide excellent wireless communication if the fundamental requirement is fulfilled—i.e., the receiver must be able to understand what the transmitter is saying.

Amplitude, Frequency, Phase

A basic sinusoid is a simple thing. If we ignore DC offset, it can be completely characterized with only two parameters: amplitude and frequency. We also have phase, which comes into play when we consider the initial state of the sinusoid, or when changes in wave behavior allow us to contrast one portion of the sinusoid with a preceding portion. Phase is also relevant when comparing two sinusoids; this aspect of sinusoidal phase has become very important because of the widespread use of quadrature (or “IQ”) signals in RF systems. We’ll look at IQ concepts later in the textbook.

As discussed above, modulation is modification, and we can modify only what is already present. Sinusoids have amplitude, frequency, and phase, and thus it should come as no surprise that modulation schemes are categorized as amplitude modulation, frequency modulation, or phase modulation. (Actually, it is possible to bridge these categories by combining amplitude modulation with frequency or phase modulation.) Within each category we have two subcategories: analog modulation and digital modulation.

Amplitude Modulation (AM)

Analog AM consists of multiplying a continuously varying sinusoidal carrier by an offset version of a continuously varying information (aka baseband) signal. By “offset version” I mean that the amplitude of the baseband signal is always greater than or equal to zero.

Let’s assume that we have a 10 MHz carrier and a 1 MHz baseband waveform:

If we multiply these two signals, we get the following (incorrect) waveform:

You can clearly see the relationship between the baseband signal (red) and the amplitude of the carrier (blue).

But we have a problem: If you look only at the amplitude of the carrier, how can you determine if the baseband value is positive or negative? You can’t—and, consequently, amplitude demodulation will not extract the baseband signal from the modulated carrier.

The solution is to shift the baseband signal so that it varies from 0 to 2 instead of -1 to 1:

If we multiply the shifted baseband signal by the carrier, we have the following:

Now the amplitude of the carrier can be mapped directly to the behavior of the baseband signal.

The most straightforward form of digital AM applies the same mathematical relationship to a baseband signal whose amplitude is either 0 or 1. The result is referred to as “on-off keying” (OOK): when the information signal is logic zero, the carrier’s amplitude is zero (= “off”); when the information signal is logic one, the carrier is at full amplitude (= “on”).

Frequency Modulation (FM) and Phase Modulation (PM)

FM and PM are closely related because frequency and phase are closely related. This is not so obvious if you think of frequency as the number of full cycles per second—what does cycles per second have to do with the position of the sinusoid at a given moment during its cycle? But it makes more sense if you consider the instantaneous frequency, i.e., the frequency of a signal at a given moment. (It is undoubtedly paradoxical to describe a frequency as instantaneous—but, in the context of practical signal processing, we can safely ignore the complicated theoretical details associated with this concept.)

In a basic sinusoid, the value of the instantaneous frequency is the same as that of the “normal” frequency. The analytical value of instantaneous frequency arises when we are dealing with signals that have a time-varying frequency, i.e., the frequency is not a constant value but rather a function of time, written as ω(t). In any event, the important point for our current discussion regarding the close relationship between frequency and phase is the following: instantaneous angular frequency is the derivative, with respect to time, of phase. So if you have an expression φ(t) that describes the time-varying behavior of the signal’s phase, the rate of change (with respect to time) of φ(t) gives you the expression for instantaneous angular frequency:

ω(t)=dϕ(t)dtω(t)=dϕ(t)dt

We’ll take a closer look at frequency and phase modulation later in this chapter. For now let’s conclude with the following plot, which applies the mathematical relationship for frequency modulation to the baseband and carrier signals used above:

                                   Summary

Modulation refers to the process of carefully modifying an existing signal so that it can transfer information.

In the context of RF, the existing signal is called the carrier, and the information is contained in the baseband signal.

There are many different modulation schemes, meaning that there are different ways of incorporating baseband information into a sinusoidal carrier wave.

Modulation involves modification of a carrier’s amplitude, frequency, or phase, and it can be used to transfer analog signals or digital data.

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

Company: Dingshengwei Electronics Co., Ltd

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

Tel: +86 0755 26909863

Fax: +86 0755 26984949

Mobile: 13410066011

Email: ken@soukacatv.com

Source: allaboutcircuits

[smartoptimus]

via Twitter https://twitter.com/smartoptimus

[soukacatv]

RF communication is built upon a simple concept: by continually altering the characteristics of a sinusoid, we can use it to transfer information.

At this point, we have covered a variety of important concepts that serve as a foundation for the successful design and analysis of real-world RF circuits and systems. We are now ready to explore a fundamental aspect of RF engineering: modulation.

HDMI Encoder Modulator,16in1 Digital Headend, HD RF Modulator at Soukacatv.com

SKD3013 3 Channel HD Encode Modulator

SKD19 Series 1U Rack 12CH Encode Modulator

What Is Modulation?

The general meaning of the verb “to modulate” is “to modify, to regulate, to vary,” and this captures the essence of modulation even in the specialized context of wireless communication. To modulate a signal is simply to intentionally modify it, but of course, this modification is done in a very specific way because the goal of modulation is data transfer.

We want to transfer information—ones, and zeros if we’re dealing with digital data, or a sequence of continuously varying values if we are working in the analog realm. But the restrictions imposed by wireless communication do not allow us to express this information in the typical way; instead, we have to devise a new “language,” or you might think of it as a code, that allows us to convey the same information but within the constraints of an electromagnetic-radiation-based system. More specifically, we need a language that is compatible with high-frequency sinusoidal signals, because such signals constitute the only practical means of “carrying” information in a typical RF system.

This high-frequency sinusoid that is used to carry information is called, appropriately, the carrier. It’s a helpful name because it reminds us that the purpose of an RF system is not to generate and transmit a high-frequency sinusoid. Rather, the purpose is to transfer (lower-frequency) information, and the carrier is simply the means that we must use to move this information from an RF transmitter to an RF receiver.

SKD121X Encoding & Multiplexing Modulator

Household Universal Encoding & Modulation Modulator

Modulation Schemes

In verbal communication, the human body generates sound waves and modifies—or modulates—them so as to produce a wide variety of vowels and consonants. Intelligent use of these vowels and consonants results in the transfer of information from the speaker to the listener. The system according to which the sound waves are modulated is called a language.

In RF communication, the situation is very similar. A device modulates electrical waves according to a predefined system called a modulation scheme (or modulation technique). Just as there are many human languages, there are many ways in which a carrier can be modulated.

It is possible that certain human languages are especially effective in conveying certain types of information; to take an example from the ancient world, perhaps Greek was better for philosophy and Latin was better for codifying laws. There is no doubt, however, that reliable communication is possible with any properly developed language, as long as the speaker and the listener both know it. The same is true for RF systems. Each modulation scheme has its advantages and disadvantages, but all can provide excellent wireless communication if the fundamental requirement is fulfilled—i.e., the receiver must be able to understand what the transmitter is saying.

Amplitude, Frequency, Phase

A basic sinusoid is a simple thing. If we ignore DC offset, it can be completely characterized with only two parameters: amplitude and frequency. We also have phase, which comes into play when we consider the initial state of the sinusoid, or when changes in wave behavior allow us to contrast one portion of the sinusoid with a preceding portion. Phase is also relevant when comparing two sinusoids; this aspect of sinusoidal phase has become very important because of the widespread use of quadrature (or “IQ”) signals in RF systems. We’ll look at IQ concepts later in the textbook.

As discussed above, modulation is modification, and we can modify only what is already present. Sinusoids have amplitude, frequency, and phase, and thus it should come as no surprise that modulation schemes are categorized as amplitude modulation, frequency modulation, or phase modulation. (Actually, it is possible to bridge these categories by combining amplitude modulation with frequency or phase modulation.) Within each category we have two subcategories: analog modulation and digital modulation.

Amplitude Modulation (AM)

Analog AM consists of multiplying a continuously varying sinusoidal carrier by an offset version of a continuously varying information (aka baseband) signal. By “offset version” I mean that the amplitude of the baseband signal is always greater than or equal to zero.

Let’s assume that we have a 10 MHz carrier and a 1 MHz baseband waveform:

If we multiply these two signals, we get the following (incorrect) waveform:

You can clearly see the relationship between the baseband signal (red) and the amplitude of the carrier (blue).

But we have a problem: If you look only at the amplitude of the carrier, how can you determine if the baseband value is positive or negative? You can’t—and, consequently, amplitude demodulation will not extract the baseband signal from the modulated carrier.

The solution is to shift the baseband signal so that it varies from 0 to 2 instead of -1 to 1:

If we multiply the shifted baseband signal by the carrier, we have the following:

Now the amplitude of the carrier can be mapped directly to the behavior of the baseband signal.

The most straightforward form of digital AM applies the same mathematical relationship to a baseband signal whose amplitude is either 0 or 1. The result is referred to as “on-off keying” (OOK): when the information signal is logic zero, the carrier’s amplitude is zero (= “off”); when the information signal is logic one, the carrier is at full amplitude (= “on”).

Frequency Modulation (FM) and Phase Modulation (PM)

FM and PM are closely related because frequency and phase are closely related. This is not so obvious if you think of frequency as the number of full cycles per second—what does cycles per second have to do with the position of the sinusoid at a given moment during its cycle? But it makes more sense if you consider the instantaneous frequency, i.e., the frequency of a signal at a given moment. (It is undoubtedly paradoxical to describe a frequency as instantaneous—but, in the context of practical signal processing, we can safely ignore the complicated theoretical details associated with this concept.)

In a basic sinusoid, the value of the instantaneous frequency is the same as that of the “normal” frequency. The analytical value of instantaneous frequency arises when we are dealing with signals that have a time-varying frequency, i.e., the frequency is not a constant value but rather a function of time, written as ω(t). In any event, the important point for our current discussion regarding the close relationship between frequency and phase is the following: instantaneous angular frequency is the derivative, with respect to time, of phase. So if you have an expression φ(t) that describes the time-varying behavior of the signal’s phase, the rate of change (with respect to time) of φ(t) gives you the expression for instantaneous angular frequency:

ω(t)=dϕ(t)dtω(t)=dϕ(t)dt

We’ll take a closer look at frequency and phase modulation later in this chapter. For now let’s conclude with the following plot, which applies the mathematical relationship for frequency modulation to the baseband and carrier signals used above:

Summary

Modulation refers to the process of carefully modifying an existing signal so that it can transfer information.

In the context of RF, the existing signal is called the carrier, and the information is contained in the baseband signal.

There are many different modulation schemes, meaning that there are different ways of incorporating baseband information into a sinusoidal carrier wave.

Modulation involves modification of a carrier’s amplitude, frequency, or phase, and it can be used to transfer analog signals or digital data.

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

Company: Dingshengwei Electronics Co., Ltd

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

Tel: +86 0755 26909863

Fax: +86 0755 26984949

Mobile: 13410066011

Email: ken@soukacatv.com

  Source: allaboutcircuits

                                              The Many Types of Radio Frequency Modulation | Soukacatv.com RF communication is built upon a simple concept: by continually altering the characteristics of a sinusoid, we can use it to transfer information.

[circuitme]

Allaboutcircuits calculators

Once upon a time one has to calculate something. A heatsink capacity, an oscillator etc. I found a few calculators on the allaboutcircuits.com. == Občas člověk potřebuje něco vypočítat. Chladič, oscilátor, cokoliv. Našel jsem, že na webu allaboutcircuits.com je pár užitečných nástrojů.

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