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

[radiolistener]

Wikipedia's definition of Digital Signal is

I wouldn’t be surprised if the text on Wikipedia was written by one of the users here who attempt to prove here that the analog signal is digital, but still cannot provide example of digital circuit which can handle non binary signal... 

A "digital PAM signal with five levels" is also given as an example and plotted in a diagram.
If this PAM signal is considered "digital", then the usual quantized staircase output of a DAC can be considered "digital", too.

PAM signal is analog signal and cannot be processed with digital circuit. PHY controller uses analog-to-digital converter to convert analog PAM signal to digital signals and process it in digital circuit. The same PHY controller uses digital-to-analog converter to convert digital signals from digital circuit to analog PAM output.

And PAM signal is not just simple 5 levels. Usually PHY controllers also use programmable gain amplifiers for tuning PAM signal amplitude. Also signal amplitude has attenuation which depends on cable length and it also needs to be taken into account. So, there is much more possible levels.

And in addition, gigabit PHY uses the same pair for transmit and receive simultaneously, it requires analog operations on signal to extract receive signal from the pair.

All this cannot be done with digital circuit and requires analog signal processing.

[wasedadoc]

No, it doesn't.  While the input and output are voltage levels, in normal use one range of voltages is considered "low", another "high", and the rest are indeterminate.  The logic is discrete, while the voltage levels used to convey that logic is continuous.

I talked about time continuity, not level.

Regarding to the level, yes digital logic is discrete, because it works with digital signals which is binary. And binary is discrete.

If you want to talk about digital logic which is not binary, then provide example of such circuit, but this circuit should be digital. You can't find it, because digital circuit requires digital signals which is binary...

And if some circuit works with non binary signals you will find that it uses analog-to-digital converter to convert analog signal to digital, process it in digital circuit and then convert back to analog with digital-to-analog converter.

There is no way to process non binary signals with digital circuit without ADC and DAC, just because digital circuit works with binary signals only. And non binary signals are not compatible with digital circuit, so you're needs to convert it from analog to digital, then process in digital circuit and then convert it back from digital to analog. 

All real signals flowing between integrated circuits using binary logic are analogue.  The inputs of those ICs have circuitry which decides if the input is to be considered a binary 0 or 1.  That is a 1-bit ADC, the simplest case of an n-bit flash ADC.

Similarly at the output of an binary IC there is a 1-bit DAC.

That binary ICs contain what are essentially ADCs and DACs is even more evident when considering binary ICs that for example operate with 3.3 Volt logic levels at input and ouput but internally use circa 1 Volt levels.

[radiolistener]

All real signals flowing between integrated circuits using binary logic are analogue.

Yes, all signals can be considered as analogue. But not all of them can be considered as digital.
The signal can be considered as digital if it uses 2 discrete levels.
Otherwise it needs to be considered as analogue and converted to digital with ADC before processing it on digital circuit.

Also note that there are different voltage standards for digital signal and if signal uses 2 discrete levels, this is not enough to claim that it is compatible with some digital circuit. It may require level shifter to adjust amplitude for compatibility.

This is why digital signal is a signal that uses binary signal levels. And analog signal is a signal that is not digital...

As you can see it well corresponds with meaning for the words "digital" and "analog" in dictionaries.  Which said that:

digital adjective:
- composed of data in the form of especially binary digits

- using a system of receiving and sending information as a series of the numbers one and zero, showing that an electronic signal is there or is not there

analog adjective:

- not digital : not computerized

[tggzzz]

The output of a sound card is indeed digital. The input is analogue. That's why the sound card is an "analogue to digital converter".

Can you please explain why any soundcard uses DAC (Digital to Analog Converter) on it's output?

In short, you're claiming that analog output of DAC is digital. If output is digital, then please explain what is the reason for DAC here?

Maybe it will help you to understand your mistake... 

Can you explain why it is called a digital to analogue converter? According to your repeated statements digital==binary and 0x1234 is analogue, so it ought to be called an analogue to analogue converter.

Or are you just trolling?

I'll be interested to hear you explain how arithmetic was (and is) done in the Harwell Dekatron (WITCH) computer, which is based on decimal logic elements, not binary logical elements.

[TimFox]

Starting in ancient Greece (Pythagoras, Euclid, etc.), there was a distinction between arithmetic and geometry in mathematics.
For a while, due to disbelief in incommensurate numbers (what we now call irrational numbers), geometry took precedence, since quantities could be represented geometrically without using numbers.
Later, arithmetic progressed with positional notation (as we use now) and the invention of zero.
Both systems are useful.  Sound familiar?
Why is a Dekatron not digital, even though it contains no binary representation?
In tggzzz' example, the Dekatron was actually in the heart of the computer, not merely a display such as a Nixie tube.
It certainly is not analog, like a sliderule.

[radiolistener]

Can you explain why it is called a digital to analogue converter?

It is called digital-to-analog converter because it converts digital signals to analog signal.
That is why it called digital-to-analog converter...

Pretty simple to understand, isn't it?

According to your repeated statements digital==binary

Previously I already stated for you that Digital != Binary. These words have different meaning.

Binary is used to identify numbering system with base 2.

Digital is used to identify digital circuit/system which uses signals with binary level, Boolean algebra, binary arithmetic and all other stuff known as "digital electronics" which is not analog and cannot handle analog signals.

0x1234 is analogue, so it ought to be called an analogue to analogue converter

I don't know what you're talking about and I never said what you're talking.

0x1234 is just a number represented in hexadecimal representation and cannot be categorized neither as analog or neither as digital.

I'll be interested to hear you explain how arithmetic was (and is) done in the Harwell Dekatron (WITCH) computer, which is based on decimal logic elements, not binary logical elements.

I don't know what is Harwell Dekatron, according to internet, this is usual digital computer which uses binary arithmetic as any other computer. So, I don't know what did you wanted to say with that 

At a glance you're just confusing information stored as digital data with digital data itself. You can store decimal or hexadecimal numbers in binary form, but it will be still information in binary format which stores some information about decimal number or something other.

[tggzzz]

If you want to talk about digital logic which is not binary, then provide example of such circuit, but this circuit should be digital. You can't find it, because digital circuit requires digital signals which is binary...

Dekatrons. They are the decimal logic elements used to implement arithmetic in the Harwell Dekatron (WITCH) computer - the oldest operating computer in the world.

See the references that I provided earlier, which show them performing arithmetic operations before printing results on a teletype.

[tggzzz]

I'll be interested to hear you explain how arithmetic was (and is) done in the Harwell Dekatron (WITCH) computer, which is based on decimal logic elements, not binary logical elements.

I don't know what is Harwell Dekatron, according to internet, this is usual digital computer which uses binary arithmetic as any other computer. So, I don't know what did you wanted to say with that 

False. It is implemented using decimal logic elements, not binary logic elements.

See this earlier post, which you seem to have conveniently ignored...
https://www.eevblog.com/forum/beginners/what-is-a-digital-system-is-it-only-binary-or-decimal-octal-as-well/msg5129826/#msg5129826

Now you have no excuse for lack of knowledge.

[radiolistener]

Dekatrons. They are the decimal logic elements used to implement arithmetic in the Harwell Dekatron (WITCH) computer - the oldest operating computer in the world.

See the references that I provided earlier, which show them performing arithmetic operations before printing results on a teletype.

ok, just read about it, if I understand correctly it uses non binary signals for computation, is it right?

If this is correct, then this Harwell Dekatron computer cannot be categorized as Digital. Technically you can name it as Decimal circuit, but such name is not common, so you can classify it as Analog circuit. But this is definitely not Digital circuit.

[tggzzz]

Dekatrons. They are the decimal logic elements used to implement arithmetic in the Harwell Dekatron (WITCH) computer - the oldest operating computer in the world.

See the references that I provided earlier, which show them performing arithmetic operations before printing results on a teletype.

ok, just read about it, if I understand correctly it uses non binary signals for computation, is it right?

If this is correct, then this Harwell Dekatron computer cannot be categorized as Digital. Technically you can name it as Decimal circuit, but such name is not common, so you can classify it as Analog circuit. But this is definitely not Digital circuit.

Everybody else knows the WITCH is a digital computer. You are the only person who has even thought of calling it an analogue computer.

You are clearly channelling Humpty Dumpty, as per a previous post.

[TimFox]

Absolute nonsense:
The Dekatron is not an analog circuit.
It is an electronic equivalent to counting on ones fingers, hence the term "digital".
"Digit" comes from the Latin for finger.
The normal Dekatron has 10 possible states, corresponding to 0,1,2,3,4,5,6,7,8, and 9, and can increment or decrement the state:  hence its usefulness for computing.
It has no valid states besides these 10, nor intermediate states along a continuum.
Have you ever seen the two words "decimal" and "digit" adjacent to each other in mathematical discussion?

[radiolistener]

The normal Dekatron has 10 possible states, corresponding to 0,1,2,3,4,5,6,7,8, and 9, and can increment or decrement the state:  hence its usefulness for computing.

just asked chat-gpt about this computer, and this is what he said:

Q: which kind of signals was used in Harwell Dekatron (WITCH) for data transfer and computations? Is that discrete level signal? How many voltage levels was used?

A: The Harwell Dekatron (WITCH) computer primarily used discrete-level electrical signals for data transfer and computations. The signals were typically binary in nature, consisting of two voltage levels: a high voltage level representing a logical "1" and a low voltage level representing a logical "0."

WITCH operated using binary-coded decimal (BCD) arithmetic and used discrete voltage levels for various signals and components. This binary representation allowed the computer to perform arithmetic operations using digital logic.

So, this Harwell Dekatron (WITCH) is Digital circuit, because it uses binary signals.

As I understand it uses BCD encoding to store numbers in his memory due to dekatron tube specific, but it doesn't affect Digital calssification, because it still uses binary signals and digital logic... 


You can store numbers in any kind of encoding in digital circuit. It doesn't matters if you store number "15" in memory as "00001111" or as "00010101". The main thing here is that you're using binary data which can be handled with digital circuit. So this kind of circuit is categorized as digital because it uses binary signals.

The same thing for ternary computer "Сетунь". It was usual digital circuit with binary signals but it was used to emulate ternary logic.
As I remember, "Сетунь" was used 2 binary signals for one ternary digit with the following encoding:
00 = 0
01 = 1
10 = 2
11 = not used (not allowed state)

[TimFox]

You can't find anything better than chat-gpt fiction?
The Dekatron is a state machine with 10 discrete states, associated with the digits 0 to 9.
It is not a binary-coded decimal device.
If you want a reasonable history of the development of digital systems, look way back in this thread to the recently-published book I cited about the development of pocket calculators.
After discussions of ancient arithmetic, there are chapters about mechanical computation devices and later electro-mechanical devices, and even later electrical devices, many of which worked in base 10, or sometimes in other bases needed for computations in situations such as the old English monetary system of pounds, shillings, and pence.

[radiolistener]

You can't find anything better than chat-gpt fiction?

I don't know about Harwell Dekatron (WITCH) internals. And google don't help to reveal how it was build under the hood. So, I asked chat-gpt as big knowledge data base.

If it provided wrong answer, then explain what is wrong?

The Dekatron is a state machine with 10 discrete states, associated with the digits 0 to 9.
It is not a binary-coded decimal device.

You can encode any type of state machine with digital circuit which works with binary signals.
You can store decimal values in a plain binary form, in BCD form, as temperature code, or whatever you want.
You can even implement unstable state and noise with digital circuit.
It all will be digital circuit which use binary signals.

But we're talking about not digital circuit which uses non-binary signals.
For example if signal can get 3 discrete values, you can implement it in different way:
- emulate on digital circuit with using two binary signals to represent one ternary signal
- use analog circuit which works directly with analog signal that represent one ternary signal

Both methos works, but first method uses digital circuit with binary signals and second method uses analog circuit with analog signals.

The same you can emulate digital signal with analog one and emulate analog signal with digital one.

The things you're talking about is just a choice of used encoding.
You cannot determine category of circuit by meaning of variable in the program that running on that circuit.

If you categorize circuit as digital just because it works with numbers, you will realize soon that such categorization is broken, because you can process number on both domains. Numbers can be processed on digital domain and on analog domain.

For example, you can implement analog calcualtor which will perform sum calculation for numbers, but such analog calculator cannot be categorized as digital supposedly because it works with numbers or because it can display numbers in decimal or hexadecimal format.

In order to categorize circuit as Analog or Digital, you're needs to see on signals type used by that circuit. If it uses binary signals you can categorize it as digital. If it uses non binary signals, then this is analog circuit.

After discussions of ancient arithmetic, there are chapters about mechanical computation devices and later electro-mechanical devices, and even later electrical devices, many of which worked in base 10, or sometimes in other bases needed for computations in situations such as the old English monetary system of pounds, shillings, and pence.

The meaning of data processed by circuit doesn't matters for Analog/Digital circuit category. The data can be binary numbers, octal numbers, decimal numbers, hexadecimal numbers, alphabet letters, hieroglyphs, or other kind of symbols or color or whatever you want, it doesn't matter for Analog/Digital category, both category can process all these things.

The device which works with numbers in base 10 can be implemented with digital circuit using binary signals.
And the same, the device which works with numbers in base 10 can be implemented with analog circuit.

The information that device works with numbers in base 10 saying nothing about Analog/Digital category of circuit which is used in this device. It can be analog or digital. The same thing for numbers with base 2, base 8, base 16, base 100500 or whatever you want base...

This is just information processed by device and you cannot make conclusion how this information is processed inside device from type of that information...

For example, you can emulate analog signals on PC and it will works with analog signals. But it doesn't means that PC is analog circuit...

[radiolistener]

The Dekatron is a state machine with 10 discrete states, associated with the digits 0 to 9.

it doesn't matters how many discrete states it have and which digits are associated with these states, or what kind of information are associated to these states.


But as I can see on that picture:



it is controlled with binary signals. Isn't it?

And since it works with binary signals it can be categorized as digital...

[Tation]

What I learned long time ago: digital = discrete-time AND quantized.

Thus, digital signal = countable sequence of symbols from some countable alphabet

Base 2 or any other base is irrelevant. Interestingly, the output of an ideal DAC, prior to the reconstruction-filter, is digital. Maybe it is because of this that such filter is called a reconstruction one, and not an smothing one.

[tggzzz]

The normal Dekatron has 10 possible states, corresponding to 0,1,2,3,4,5,6,7,8, and 9, and can increment or decrement the state:  hence its usefulness for computing.

just asked chat-gpt about this computer, and this is what he said:

You seem not to be aware of the the LLM phenomenon of "hallucination"?

[tggzzz]

What I learned long time ago: digital = discrete-time AND quantized.

Thus, digital signal = countable sequence of symbols from some countable alphabet

Base 2 or any other base is irrelevant. Interestingly, the output of an ideal DAC, prior to the reconstruction-filter, is digital. Maybe it is because of this that such filter is called a reconstruction one, and not an smothing one.

Quantisation is the important point, since the "forbidden zone" between the individual symbols allows the digital signal to be losslessly regenerated by a receiver.

It doesn't have to be discrete-time; asynchronous logic doesn't have a clock.

Most digital circuits are clocked, since analysing larger asynchronous circuits rapidly becomes intractable. You have to consider all state-space transitions that might occur when more than one input changes at the same time.

[radiolistener]

You seem not to be aware of the the LLM phenomenon of "hallucination"?

I know, but I don't see any indication that what it said is false.
I added picture above from wiki with example of dekatron cyclogram and it shows that it is controlled with binary signals. Isn't it?

Correct me if I'm wrong, but dekatron can be replaced with 74HC4017. Isn't it?

So there is no any magic and no non binary signals, dekatron is classic digital counter with binary signals...

[Nusa]

While I've a large professional background in software and a lengthy amateur hobby in electronics, I'll skip all that and go for a simple proof.

Analog clock = round thing with hands most of us are familiar with.
Digital clock = Box with a decimal digit display of some type that most of us are also familiar with.
Binary clock = Box with a bit-based display of some type that is more of a novelty item for professionals, but does exist.

Note that the words "binary" and "digital" clearly are not the same here.
One example is sufficient to disprove the claim that binary and digital are aways synonyms.

[tggzzz]

You seem not to be aware of the the LLM phenomenon of "hallucination"?

I know, but I don't see any indication that what it said is false.

Your lack of understanding won't surprise any of the other contributors to this thread.

Not being able to recognise when an LLM is hallucinating is becoming a serious problem for society; one lawyer in the US is in trouble because he tried to argue his client's case based on case law that turned out to have been invented by a hallucinating LLM.

Apart from that, it is quite amusing to review your posts in this thread. The evolution of your statements about digital/analogue/binary/hex/analogue/etc reminds me never to forget that "there is no such thing as a true Scotsman".

[radiolistener]

Your lack of understanding won't surprise any of the other contributors to this thread.

Listen, I know about chat-gpt issues very well and I don't blind believe to all what he said. On the contrary I think that chat-gpt is very stupid, but it has good database and often provides good finding.
And in this case what he said looks pretty precise. Isn't it?

I read more about dekatron and it seems that this is just a tube version of classic digital counter which works with binary signals.

And it seems that you can replace dekatron tubes with some small modern circuit like 74HC4017 and a couple of LED's. Isn't it?

So, I don't see that chat-gpt was wrong when he said that Harwell Dekatron (WITCH) works with binary signals with discrete 1 and 0.

And I don't see here any usage for signal with 10 discrete levels. Dekatron don't use it. It uses classic binary signals. This is classic digital circuit.

[radiolistener]

Apart from that, it is quite amusing to review your posts in this thread. The evolution of your statements about digital/analogue/binary/hex/analogue/etc reminds me never to forget that "there is no such thing as a true Scotsman".

What kind of evolution do you mean? My statement is always was that digital is circuit that uses binary signals and analog is all signals which is not digital. This is pretty simple and there is no change in my statement. Just explanation of this simple thing with a lot of examples and details.

Explanation for binary/hex format was provided for you. Just because you're confuse information about something (number or something else) encoded in digital data with digital data itself.

this is yours statement has constantly evolution, you're trying to find different examples to name non binary signal as digital, but I show you examples again and again that your classification is broken and don't works. Isn't it?

For example you said that dekatron uses decimal signals and is named as digital, but it appears that this is false claim and dekatron is classic digital counter with binary signals...

What will be your next example? 
Seriously, it's funny to see how you're trying to refute simple and clear things.

Here was a funny example of your attempt to classify number as analog or digital thing... 

Can you explain why it is called a digital to analogue converter? According to your repeated statements digital==binary and 0x1234 is analogue, so it ought to be called an analogue to analogue converter.

It also clearly shows that you are trying to manipulate by attributing to me statements that I have never made.

Just for your information, number is a number, you cannot classify number as digital or analog.
And it don't depends in which format you wrote that number bin/dec/hex or something else. Category digital or analog can be applied to implementation of storage which stores or transfers information about that number, but not to a number itself.

Signal or circuit can be digital or analog.
Number cannot be digital or analog. 

[golden_labels]

My cup of popcorn is almost empty. Perhaps it’s time to stop? Any attempt to discuss the topic only gives them an excuse to post more sophisms and increase the volume of incorrect information in the thread. A random reader is more likely to find their post instead of anything of value posted earlier and it gets even worse with each response.

[tggzzz]

My cup of popcorn is almost empty. Perhaps it’s time to stop? Any attempt to discuss the topic only gives them an excuse to post more sophisms and increase the volume of incorrect information in the thread. A random reader is more likely to find their post instead of anything of value posted earlier and it gets even worse with each response.

I quite agree.

I thought of posting a list of some of radiolistener's more entertaining statements, but decided life is too short and it would serve no useful purpose (Humpty Dumpty, Scotsman).

I hope and expect that if anybody blunders into this thread in the future, they will see the balance between radiolistener and other posters.