What defines a digital or analogue circuit?

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samuraipizzacat29
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Re: What defines a digital or analogue circuit?

Post by samuraipizzacat29 » Thu Jun 21, 2012 3:16 pm

you're a little late to the party:
Thus, a pulse/square wave is an analog wave, but if you define the top of the wave as "one" state and the bottom of the wave as "the other" state, then you're using the wave "digitally" -- that the amplitude of the wave is capable of representing one of two different numbers. Same wave in either case; it just depends on how it's being used and interpreted.
So, if the wave were not being "interpreted" how would you define it?
If the wave is being interpreted according to whether it falls into two or more discrete ranges, you're interpreting it digitally. If it's not being interpreted that way, it's analog.
As you'll notice, the first post I made (i'm sorry if you weren't a part of that thread) clearly demonstrates the point that a digital waveform is intended to contain information based on it's logic state. it is a means, not an end.
If it were a digital output, it would need D/A converters.
I apologize if my explanations got wordy, overwhelming or unclear. I have actually apologized for that multiple times. It's difficult to explain things in words. Additionally, responding to forum comments one at a time from multiple different sources can be quite cumbersome.

Yet, your denigration of my intelligence based on your perception adds nothing to this conversation. If you don't understand the topic at hand, then I would suggest you take your own advice and bow out.

honestly, i'm exhausted from responding to comments clearly intended to deride my knowledge (or lack) when it seems pretty clear that it's important to me to understand all of the aspects involved in considering this topic.

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Re: What defines a digital or analogue circuit?

Post by tallowwaters » Thu Jun 21, 2012 3:27 pm

samuraipizzacat29 wrote:
Yet, your denigration of my intelligence based on your perception adds nothing to this conversation. If you don't understand the topic at hand, then I would suggest you take your own advice and bow out.
I'm not making a judgement of your intelligence, merely your understanding of the topic at hand and your willingness to seemingly ignore all the facts presented to you, all while arguing in a futile fashion. I wasn't trying to deride you in you any way, merely giving you a perspective on how your behavior is being perceived by people outside your participation in this thread. If you read it and thought Person 1 was acting foolish, then you could most certainly see some folk's view of your role in this thread.
Brains can be used like a "stress ball," but only once.

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Re: What defines a digital or analogue circuit?

Post by redchapterjubilee » Thu Jun 21, 2012 4:06 pm

tallowwaters wrote:It only seems like he is talking down to you because he has been telling you the same thing for the entire thread, which can be a bit frustrating from the point of view of somebody trying to teach, only to have the subject of such teaching seemingly refuse to acknowledge the facts in front of him.

For example:

Person 1: Where is the peanut butter?
Person 2: Top shelf of the pantry.
Person 1: I've already looked in the fridge
Person 2: Uhhh... Okay, now look on the top shelf of the pantry
Person 1: I've looked on the floor in the pantry, not there
Person 2: Dude, top shelf
Person 1: I went into your bedroom and pulled out all of your drawers, still no peanut butter
Person 2: Are you f**k with me?
I have to say though, this guy's seeming inability to understand what those who truly know what they are talking about have presented in a rather straightforward method has been really beneficial at least to me. I've never really read this tireless age-old "VCO vs. DCO" argument in this particular light, nor with this much good information. The "discussion" has pulled some great contributions out of folks who've been around here forever and REALLY know what they are talking about. At least I've been educated. I don't know s**t about science and even I'm beginning to figure it out. Thanks all!
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Re: What defines a digital or analogue circuit?

Post by Dr. Phibes » Thu Jun 21, 2012 4:22 pm

Digital implies the presence of an evil little black chip, designed solely to denude the immediate vicinity of orgone energy, that thereby renders any instrument within its zone of effect without vibe whilst at the same time significantly reducing ambient levels of phatness. These are facts.
Last edited by Dr. Phibes on Fri Jun 22, 2012 5:44 am, edited 2 times in total.

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Re: What defines a digital or analogue circuit?

Post by cgren72 » Thu Jun 21, 2012 4:29 pm

Dr. Phibes wrote:black chip
so now you are pulling race into this? :lol:

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Re: What defines a digital or analogue circuit?

Post by implant » Thu Jun 21, 2012 4:55 pm

redchapterjubilee wrote: I have to say though, this guy's seeming inability to understand what those who truly know what they are talking about have presented in a rather straightforward method has been really beneficial at least to me. I've never really read this tireless age-old "VCO vs. DCO" argument in this particular light, nor with this much good information. The "discussion" has pulled some great contributions out of folks who've been around here forever and REALLY know what they are talking about. At least I've been educated. I don't know s**t about science and even I'm beginning to figure it out. Thanks all!
Right on! this is a good thread.

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Re: What defines a digital or analogue circuit?

Post by Dr. Phibes » Thu Jun 21, 2012 5:20 pm

cgren72 wrote:
Dr. Phibes wrote:black chip
so now you are pulling race into this? :lol:
Hey, it's those nefarious digital doohickeys that want to segregate everything into one type or the other. It's racialism at the quantum level.

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samuraipizzacat29
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Re: What defines a digital or analogue circuit?

Post by samuraipizzacat29 » Thu Jun 21, 2012 5:27 pm

i'm doing some more reading and will report my findings back asap. You guys will like this because everyone's right and everyone's wrong (including me). clarification on the way :)

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Re: What defines a digital or analogue circuit?

Post by clubbedtodeath » Thu Jun 21, 2012 7:25 pm

samuraipizzacat29 wrote:i'm doing some more reading and will report my findings back asap. You guys will like this because everyone's right and everyone's wrong (including me). clarification on the way :)
Any more shite fae you and Ah'm getting The Babs oot. Consider yourself warned!

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Re: What defines a digital or analogue circuit?

Post by samuraipizzacat29 » Thu Jun 21, 2012 7:44 pm

got a poly 800 service manual? i'm trying to find one and can't. joined the poly 800 yahoo group but haven't received mod approval yet. they're probably reading this thread....... ;)

edit, nm, found one. will report soon.

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Re: What defines a digital or analogue circuit?

Post by clubbedtodeath » Thu Jun 21, 2012 8:22 pm

Have you considered what defines an arsehole?

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Re: What defines a digital or analogue circuit?

Post by stillearning » Thu Jun 21, 2012 11:30 pm

After a brief read through this thread, I felt the need to jump on a tractor and mow a few acres. Now I'm going to jump in the shower, then jump on a leggy blond. I suggest the rest of you follow suit.
As always, kindly allow for the possibility I have no idea what I'm talking about.

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Re: What defines a digital or analogue circuit?

Post by Bitexion » Thu Jun 21, 2012 11:35 pm

You guys need to stop going after the Person, and stay on the topic instead. Making a dozen posts about why some guy is wrong derails the whole thread.

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Re: What defines a digital or analogue circuit?

Post by rschnier » Thu Jun 21, 2012 11:53 pm

samuraipizzacat29 wrote:
rschnier wrote:
Steve Jones wrote:Are c**p old Italian organs or Realistic MG-1's digital synths? They use digital dividers to get their note frequencies. Spooky. :shock:
Yes, in that case at least the tone generation part is digital.........hammond novachord has digital elements in it, even though it's implemented with tubes/vales!
I don't understand. This is a contradiction to what you previously wrote. if the divide-down circuit is the direct output (even though these are square waves) how can this be referred to as digital?

is the point that you're comparing/using the leading/trailing edges of a wave to control a flip flop and since this is a function the theory of which is digital in nature (it's a logic operation), that we're calling it a digital operation? Yet, if that's the output that we're hearing, then those waves are analog, no?

I'm asking because I'm genuinely confused now.

If that's what you're saying, then it provides further insight into what we call a DCO, because in that case I think we'd say that everything up to the switching operation is a digital operation. yet, because the switching operation creates a wave that is intended to be disseminated by our ears, that can be considered an analog signal. Even the switch itself is digital, but the output is analog. (just hashing it out in my brain and typing accordingly)

I would have considered the operation itself analog because it's a physical change. But if the operation is digital because you're analyzing a high/low state, then I can understand why that would be true. fun times.....
I thought someone might ask that, so during the day today I thought about how best to answer it. Here goes:

The divide-down circuit is digital because it has two discrete internal states:
  1. A state where it's receptive to being reset, and
  2. A state where it's not receptive to being reset.
Which state the circuit is in, is determined by whether its output voltage is less than a certain "threshold" value, or greater than that value. (Remember from the last discussion: a digital circuit is a kind of analog circuit in which we've assigned meaning to the circuit's states based on whether a parameter of the circuit -- usually its output voltage -- falls into one range or another range.) Here, we've designed our circuit so that if its output voltage is less than the threshold value, the circuit is not receptive to being reset...while if the output voltage is greater than the threshold value, the circuit is receptive to being reset. Two ranges, two states. For simplicity, let's define the threshold value to be 50% of the high-limit voltage of the circuit. Furthermore, let's say that after being reset, the divider circuit's output voltage starts out at zero, then increases over time, and when the circuit is reset, the voltage drops back to zero again. (You can easily get this behavior by charging a capacitor with a controlled current -- it's exactly like filling up a glass of water from the faucet.)

Since the above was a mouthful, here's another way to imagine it. You have a drinking glass that you're filling with a stream of water from the faucet. Someone might tell you to dump the glass out at anytime, but you've decided that you're going to ignore them unless the glass is more than than half full of water. Again, two states:
  1. A state where you'll ignore the person telling you to dump the glass (it's less than half full) and
  2. A state where you'll dump the glass when they ask you to (greater than half full).
Still with me? OK, now let's talk about the waveform that we're feeding into this divider circuit. It's going "up and down" in voltage at a certain rate. For this example, let's say it goes from "zero voltage" to "high voltage" and back to "zero voltage" 100 times per second. If you fed that voltage into an amp and loudspeaker, you'd hear a tone at 100 Hz. Thus, the waveform goes from zero to high and then back to zero voltage in 0.01 seconds (1/100 of a second).

Now, let's say that our divider circuit is designed so it's going to take about 0.25 seconds -- the exact time is not important as long as it's more than 0.2 seconds -- to go from zero voltage to its maximum voltage (in other words, we're filling the drinking glass at a rate so the glass is full in about a quarter of a second).

OK. Now we feed the input waveform -- cycling at 100 times per second -- into the divider circuit. As mentioned before, the divider circuit's output voltage starts at zero and then increases so that it's at maximum in 0.25 seconds. (Filling the drinking glass from the faucet.)

After 0.1 seconds, the input waveform is going to be back at zero voltage. (It's gone from zero to high and back to zero voltage again, in 0.1 seconds.) But after 0.1 seconds, the divider circuit's output voltage is not going to be over 50% of max voltage yet -- it takes 0.125 seconds for it to reach 50%. So the divider circuit ignores the request to "dump its glass of water" and does not reset its output voltage back to zero at this time.

OK, after 0.125 seconds, the divider circuit's output voltage has now increased to 50% of maximum voltage. At this point, the divider circuit has changed states -- it's gone from "ignore reset request" state to "obey reset request" state. And again, this change of state is determined solely by whether the output voltage falls into one range vs. another -- under 50% of maximum vs. over 50% of maximum.

After 0.2 seconds, the input waveform is back at zero voltage again. The last time this happened (at 0.1 seconds), our divider circuit ignored this and let its output voltage keep increasing on its merry way. But now, the output voltage is over 50% of maximum, which it wasn't before, and this time the divider circuit obeys the signal from the input waveform to reset its output voltage back to zero. The result of all this is that the output voltage of the divider has been made to go from zero to high voltage and back to zero again in 0.2 seconds, exactly half the rate at which the input voltage of the divider has gone from zero to high voltage and back to zero again (0.1 seconds). Note that the divider would normally take 0.25 seconds for its output voltage to reach maximum and stop climbing, but by defining two distinct ranges for the output voltage and using those ranges -- states -- to determine whether we're going to obey a reset request or not, we've "synced" the two waveforms so that one cycles at exactly half the rate of the other. (That's why it doesn't matter whether the divider's normal min-to-max time is exactly 0.25 seconds or not -- anything over 0.2 seconds will do the job -- but we don't want it to be too far over 0.2 seconds.)

It's all about whether the circuit has multiple, discrete states or not.
-- R.

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Re: What defines a digital or analogue circuit?

Post by theglyph » Fri Jun 22, 2012 5:01 pm

It seems like most of the essence of the thread title has perhaps been lost and Tallowwaters picked up on that.

I define digital as software based sound generation/manipulation requiring a DAC to communicate with the outside world and analog as all other methods. I understand that a grey line exists when people question if Lunetta's are digital or analog. CMOS is both digital and analog but IMO as It needs capacitors and resistors to make things work and there is no need for a DAC it's still analog in nature.

As for DCO's they are analog but probably not as analog as purists would like (Marc ;).

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