What is a digital system? Is it only binary or decimal, octal as well?

[radiolistener]

But in English and general engineering, you are wrong. Full stop.

It doesn't depends on language.

If you're talking that input of your circuit is digital then anyone can understand that it accept only binary signals which can be 1 or 0, and it don't accept other levels.

When you're talking that input of your circuit is analog then anyone can understand that it can accept more than two levels.

People who knows usual electronics and discrete math expecting binary state for digital signals and Boolean logic for digital logic elements. If you use term digital for analog discrete signal with 4 levels it breaks existing terminology and it leads to confusion.

Just for your information, if you use discrete signal with 3 and more possible levels then classic Boolean logic is no more applicable for such signal and it means that all existing digital electronics cannot be used to process your signal without conversion to digital domain. You're needs to use different math with different rules to process such signal directly without conversion to digital domain. It will be ternary domain with ternary logic and ternary math with it's own ternary laws and rules.

This is why digital electronics is common, and you cannot find electronics with ternary logic and math. There are only two common domains in electronics - digital and analog. It is possible to research ternary math and maybe develop electronics based on ternary logic, but this is complicated and not common for a usual electronics. So there is no electronics which uses ternary math.

[tooki]

radiolistener:
This is complete bullshit, contrary to actual usage, supported by a comically failed attempt in appeal to authority. You could at least read the backlog, where people working in the industry for decades share their experience or give actual examples.

"This is complete bullshit" - this is what you will hear when you try to provide some signal which has 4 levels on digital GPIO pin of some controller and ask firmware developer to handle all 4 levels because this is "digital" signal...  And I will agree with him, because this is really complete bullshit.

If you're talking that the signal is digital, it should have two possible state 1 or 0.

And when you're talking that analog discrete signal with possible 4 levels is "digital", this is complete bullshit. Because there is no digital logic circuit that supports signal with 4 possible states.

You can name digital signal as analog and analog as digital for yourself, but if you're want so other people can understand you, you should use term digital for signals with 2 possible levels 1 and 0. And use analog term for signals which can have more than 2 possible levels.

This is an invalid argument[/b], but since you considered it ok and it may be worth waking you up from your denial of reality, here is what your own sources say about word “analog”

I don't needs to walk. Analog signal means that signal IS NOT DIGITAL. So, any signal which has more than 2 possible levels is analog. This is pretty easy...

In order to process analog signal in digital domain you're needs to convert it from analog domain to digital domain. And in order to generate analog signal from digital domain you're needs to convert from digital domain to analog domain. There is no way to process analog signal in digital domain without converting. And you're needs to learn the difference between analog domain and digital domain to avoid confusing them.

This is very simple:
- Digital signal has two possible states: 1 and 0.
- Analog signal has more than two possible states.

Grouping of several signals don't change their type. If you have 8 lines and all are digital, then this is digital bus, not analog. The same if you use 8 lines and all are analog, then this is analog bus, not digital.

You are dead wrong, sorry.

As others have said: binary is a subset of digital.

Analog means that a continuous value changes in proportion to the information. For example, amplitude of a sound waveform: this modulates the amplitude of the carrier wave in AM radio, or the carrier frequency in FM.

In contrast, in a digital system, the values are discrete (they can only take one of a fixed set of values), and those values need not correlate directly to the information being encoded. In digital audio, even if uncompressed, the individual digits do not correlate to a particular amplitude. In typical PCM encoding, the entire word needs to be a) identified, and b) interpreted, in order to derive an amplitude value.

It’s true that in electronic signaling, most digital signals and circuits are binary. But not all are, and telecommunication signals frequently use non-binary representations of digital data. The fact that they encode informatikn using multiple levels (and in many, phase shifts) doesn’t make it analog, because the encoding doesn’t change in proportion to the information itself. Other than memory, I’m not aware of any digital logic that uses multilevel signaling, so in the context of practical digital circuit design other than telecommunications, yes, digital means binary. But not because they’re synonyms, but simply because “digital excluding telecom” is a set containing only one member in practice.

All digital signals live in the analog domain, insofar as the physics of the real world are analog. So what we really mean when we say that a signal is digital (whether binary or otherwise) is that we are interpreting it in a digital way. This layer of abstraction is one thing that makes digital so useful, because noise can be ignored to an extent, since the physical signal is not an analog of the information.

And let’s not forget that there are quasi-analog signals that take only two states, like pulse width modulation and pulse density modulation. And indeed, with simple analog filtering, true analog signals can be extracted from them. (You can’t take a PCM bitstream and analog filter it to get audio.)

[tooki]

But in English and general engineering, you are wrong. Full stop.

It doesn't depends on language.

If you're talking that input of your circuit is digital then anyone can understand that it accept only binary signals which can be 1 or 0, and it don't accept other levels.

When you're talking that input of your circuit is analog then anyone can understand that it can accept more than two levels.

People who knows usual electronics and discrete math expecting binary state for digital signals and Boolean logic for digital logic elements. If you use term digital for analog discrete signal with 4 levels it breaks existing terminology and it leads to confusion.

Just for your information, if you use discrete signal with 3 and more possible levels then classic Boolean logic is no more applicable for such signal and it means that all existing digital electronics cannot be used to process your signal without conversion to digital domain. You're needs to use different math with different rules to process such signal directly without conversion to digital domain. It will be ternary domain with ternary logic and ternary math with it's own ternary laws and rules.

Boolean logic is indeed binary.

But a system that takes 256 bits (bit = binary digit) and encodes them to a single symbol (like the combination of phase and amplitude in QAM) is still digital, because the signal is not an analog of the information being transmitted. Neither the amplitude nor the phase correlate to any aspect of the information. For example, if you were using it to transmit audio, neither amplitude nor phase of the QAM signal correlates to the amplitude value of the audio. And it’s also not analog by definition, insofar as it’s noncontinuous — there are discrete symbols being sent, not a continuously-variable (= stepless) signal.

[radiolistener]

As others have said: binary is a subset of digital.

This is wrong claim. Digital electronics works with binary signals and uses Boolean logic.

It seems that you're just confusing term Numerical with Digital, because things that you're talking about "digital" looks like usual Numerical term.

Analog means that a continuous value changes

It seems that you're confusing terms Digital/Analog with Discrete/Continuous...

Signal or circuit can be digital (binary) or analog (non binary).
And signal can be discrete or continuous.

Please don't confuse term digital with term discrete. These are different thing with different meaning.

[radiolistener]

But a system that takes 256 bits (bit = binary digit) and encodes them to a single symbol (like the combination of phase and amplitude in QAM) is still digital, because the signal is not an analog of the information being transmitted.

This is incorrect understanding. QAM modulated signal is analog signal which is used to transmit digital data.

The system which generate QAM signal can use digital computation in digital domain (with using binary signals and boolean logic) to calculate analog signal in digital representation and then convert it with DAC to analog domain. But it don't means that QAM modulated signal is digital.

You can generate QAM with analog circuit, but it will be much more complicated and expensive than doing it in digital domain due to analog circuit limitations.

If analog signal carrying digital data it don't means that this signal is digital. In order to be assumed as digital, the signal must be binary.

[alm]

Radiolistener vs the world claiming that digital = binary, deja vu 

[radiolistener]

Radiolistener vs the world claiming that digital = binary, deja vu 

It is very reckless to call several forum users who confusing terminology as the "world"...
Yes, we already discussed that subject in the past.

[tggzzz]

Given the origins of the word digital, if it is restricted to only a single number base, then that must be decimal.

Origin of word digital is a binary signal which controls correspond digit on Nixie tube.

Wrong (again).

First nixie displays in 1955: https://en.wikipedia.org/wiki/Nixie_tube

First use of digital: "Mathematician George Stibitz of Bell Telephone Laboratories used the word digital in reference to the fast electric pulses emitted by a device designed to aim and fire anti-aircraft guns in 1942." https://en.wikipedia.org/wiki/Digital_signal_(electronics)

[tggzzz]

But a system that takes 256 bits (bit = binary digit) and encodes them to a single symbol (like the combination of phase and amplitude in QAM) is still digital, because the signal is not an analog of the information being transmitted.

This is incorrect understanding. QAM modulated signal is analog signal which is used to transmit digital data.

A QAM waveform is indeed analogue, just as all waveforms are analogue. That concept is a pre-requisite for understanding the importance of signal integrity in digital electronic systems.

Those analogue waveforms are quantised into discrete levels representing digital signals.

Summary: tooki has understood it correctly, but you haven't.

[tggzzz]

Radiolistener vs the world claiming that digital = binary, deja vu 

It is very reckless to call several forum users who confusing terminology as the "world"...
Yes, we already discussed that subject in the past.

Many people use terms incorrectly, e.g. specifying time in nS (not ns), or specifying battery capacity in MW (not MWh), or scope bandwidth in mHz.

In this case you are using terms incorrectly.

[radiolistener]

First nixie displays in 1955: https://en.wikipedia.org/wiki/Nixie_tube

First use of digital: "Mathematician George Stibitz of Bell Telephone Laboratories used the word digital in reference to the fast electric pulses emitted by a device designed to aim and fire anti-aircraft guns in 1942." https://en.wikipedia.org/wiki/Digital_signal_(electronics)

It doesn't matter, modern term digital means that system works with binary signals and Boolean logic.

Regarding to QAM. To be clear. Digital data in this context is the message signal carried over analog signal. Don't confuse message signal with analog signal which carries that message.

[radiolistener]

In this case you are using terms incorrectly.

What I'm using incorrectly?

I don't confuse terms "Digital" and "Discrete" like you. For me digital and discrete are different things.
Digital means system works with binary signals and uses Boolean logic (in opposite to analog).
Discrete means that system works uses discrete signal representation (in opposite to continuous).

[radiolistener]

Those analogue waveforms are quantised into discrete levels representing digital signals.

It seems that you're confusing terms "modulated signal" and "message signal".
QAM is modulated signal and it is analog.
Message signal can be analog or digital.

Modulated signal carries message signal, but if you use digital message signal it don't turns modulated signal into digital, it still remains analog.

For example CW modulation expects digital message signal (binary 1 and 0), but modulated CW signal is analog signal and cannot be assumed as digital despite the fact that it carries digital signal.

[wasedadoc]

Origin of word digital is a binary signal which controls correspond digit on Nixie tube.

Origin of the word "digital" is the Latin word "digitus" meaning "finger" or "toe".

[tggzzz]

First nixie displays in 1955: https://en.wikipedia.org/wiki/Nixie_tube

First use of digital: "Mathematician George Stibitz of Bell Telephone Laboratories used the word digital in reference to the fast electric pulses emitted by a device designed to aim and fire anti-aircraft guns in 1942." https://en.wikipedia.org/wiki/Digital_signal_(electronics)

It doesn't matter, modern term digital means that system works with binary signals and Boolean logic.

It is revealing that you chose to omit the context in order to make your point. The context invalidates your response.

You made the explicit incorrect statement highlighted below...

Given the origins of the word digital, if it is restricted to only a single number base, then that must be decimal.

Origin of word digital is a binary signal which controls correspond digit on Nixie tube.

Wrong (again).

First nixie displays in 1955: https://en.wikipedia.org/wiki/Nixie_tube

First use of digital: "Mathematician George Stibitz of Bell Telephone Laboratories used the word digital in reference to the fast electric pulses emitted by a device designed to aim and fire anti-aircraft guns in 1942." https://en.wikipedia.org/wiki/Digital_signal_(electronics)

General principle: when you are in a hole, stop digging.

[radiolistener]

It’s true that in electronic signaling, most digital signals and circuits are binary.

I will open you some secret, in digital electronics all signals are binary, that is why it digital

But not all are, and telecommunication signals frequently use non-binary representations of digital data.

In telecommunications analog signals are used to carry digital message signals, but it don't turns analog signals into digital. As said above, for example CW modulated signal carries digital signal, but CW modulated signal cannot be assumed as digital just because consists of sine with varying amplitude which cannot be represented with digital signal (with binary levels 1 and 0).

The fact that they encode informatikn using multiple levels (and in many, phase shifts) doesn’t make it analog

For modulated signal doesn't matters what you're using as modulation message signal - digital or analog. If modulated signal is analog it will remains analog. And you cannot name analog signal with varying phase and amplitude as digital just because it cannot be represented with binary 1 and 0.

[tggzzz]

In this case you are using terms incorrectly.

What I'm using incorrectly?

I suggest you slowly read and understand the technical references several people have given to you.

Start with https://en.wikipedia.org/wiki/Digital_signal#In_digital_electronics
and pay particular attention to the sections "In digital electronics", "In signal processing", and "Modulation".

[radiolistener]

I suggest you slowly read and understand the technical references several people have given to you.

Start with https://en.wikipedia.org/wiki/Digital_signal#In_digital_electronics
and pay particular attention to the sections "In digital electronics", "In signal processing", and "Modulation".

Wikipedia is often written by people who don't know the subject very well. I don't want to read long texts and guess what did you mean when proposed to read that link....

Just give me answer on the question - where I'm wrong?

If you're think that I'm complete noob and don't know what I'm talking about, just for your information, I have college and university degree in digital electronics and software development and worked for many years as software development engineer, I know digital signal processing and have experience in designing my own DSP chains for short wave receivers. I implemented CW,SSB,AM,FM demodulators in digital domain using different approaches and tested how they works with real air signals. I done it in FPGA as digital circuit and in software as a program. I'm licensed ham amateur and know technical details about antennas, radio waves, spectrum, modulation, how all these things works in analog domain and from physics point of view. So, don't hesitate to point me where I'm wrong exactly... 

As any people I can be wrong, but if you want to say that I'm wrong, then please provide me with logically correct and clean reason. Not abstract "you're wrong go and read RTFM".

Currently I see that you're confusing terminology (terms Digital, Discrete, Numerical) and cannot provide clean and logical point of view. In addition I see that you don't understand well theory about signal modulation and confusing modulated signal with modulation message signal. For some reason you're don't want to accept classic meaning of term Digital and want to name analog signals and circuits as digital just because it can be used to carry digital data. Sorry, but I cannot accept so confusing arguments.

[BeBuLamar]

So if Hex or Decimal is not digital then they are analog?
The French doesn't call it digital but they call it Numerique vs Analogue.

[radiolistener]

So if Hex or Decimal is not digital then they are analog?

Hex and Decimal are numbering systems. It is not about analog/digital, but about different systems for number representation.

If you want to use hex or decimal digit to represent signal, it requires to process signal with 10 or 16 levels. There is no logic and math developed for such signals, so - yes, such signals are analog, because they are not digital and other kind of signal just don't exists in modern electronics. In theory it is possible to develop, but it requires a lot of work starting from math development and research for such systems.

As far as I know, such work is not being carried out. There was some attempts to research ternary logic, but it seems that it is not widespread. I think this because it is complicated and don't provide you with some benefit in comparison with digital electronics.

So, there are only two common domains in electronics - digital and analog.

[tggzzz]

I suggest you slowly read and understand the technical references several people have given to you.

Start with https://en.wikipedia.org/wiki/Digital_signal#In_digital_electronics
and pay particular attention to the sections "In digital electronics", "In signal processing", and "Modulation".

Wikipedia is often written by people who don't know the subject very well. I don't want to read long texts and guess what did you mean when proposed to read that link....

Wikipedia is often written by people who do know the subject very well. The wackypedia article is one such article.

If you aren't prepared to listen to answers and think about the responses, then there is no point in others trying to help you.

Just give me answer on the question - where I'm wrong?

See the previous responses from myself and many other people.

[radiolistener]

Wikipedia is often written by people who do know the subject very well. The wackypedia article is one such article.

If you aren't prepared to listen to answers and think about the responses, then there is no point in others trying to help you.

Sorry, but if you don't have answer, it's better to be quiet instead of engaging in chatter to dodging the answer.

I still don’t see what exactly you disagree with... And I didn't asked help about this topic.

[BeBuLamar]

So if Hex or Decimal is not digital then they are analog?

Hex and Decimal are numbering systems. It is not about analog/digital, but about different systems for number representation.

If you want to use hex or decimal digit to represent signal, it requires to process signal with 10 or 16 levels. There is no logic and math developed for such signals, so - yes, such signals are analog, because they are not digital and other kind of signal just don't exists in modern electronics. In theory it is possible to develop, but it requires a lot of work starting from math development and research for such systems.

As far as I know, such work is not being carried out. There was some attempts to research ternary logic, but it seems that it is not widespread. I think this because it is complicated and don't provide you with some benefit in comparison with digital electronics.

So, there are only two common domains in electronics - digital and analog.

A hex digit is only 2 levels but 4 bits in parallel. All things involving hex, octal are also binary in nature. When you use Hex or Octal you're talking about a digital system.

[tggzzz]

Wikipedia is often written by people who do know the subject very well. The wackypedia article is one such article.

If you aren't prepared to listen to answers and think about the responses, then there is no point in others trying to help you.

Sorry, but if you don't have answer, it's better to be quiet instead of engaging in chatter to dodging the answer.

I still don’t see what exactly you disagree with...

I refer you to the last line of my previous response which - again - you have chosen to omit. Not impressive.

Here it is again: "See the previous responses from myself and many other people".

[radiolistener]

A hex digit is only 2 levels but 4 bits in parallel. All things involving hex, octal are also binary in nature. When you use Hex or Octal you're talking about a digital system.

if you want to represent hex digit with single signal it requires 16 levels. Such signal is analog.
Grouping binary signals don't changes signal type it still binary.
So if you're using many binary signals, it doesn't means how much, it still will be digital system.