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Stream Operator
Joined: Oct 13, 2007 Posts: 6221 Location: near Austin, Tx, USA
Audio files: 267
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Posted: Wed Dec 28, 2016 12:52 am Post subject:
Frequently Accurate Sine Waves? Subject description: ...with the emphasis on "Freq"... |
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I have a really stupid question. I admit that I don't know much about oscillators. I just have a clunky non-expert sort of perspective on them so I'd appreciate someone's knowledge on this point. Also I think it is well known so I just don't know about it. It goes like this...
When you use a multimeter it's got like three maybe four digits of precision. Scope not so many either, function generator very accurate I suppose but it's a big clunky thing. When you look at a frequency meter, it tells you 100.000000... out the wazzooo with zeroes. The point I'm making i guess is that time is way more accurate than any other means of measurement.
So I think of our oscillators and I imagine... Why not make an oscillator with a time dependence. Something just a step up in complexity (a bit more complex unfortunately) from the basic oscillator that does the job very well. I can think of some circuits, but I'll just leave it at that for now...
If we begin with the premise of clocking our sine wave oscillator in some way, won't it naturally be astoundingly accurate? Like synthesis with a Karplus Strong thingie with a band pass circuit in the feedback loop? Am I just being stupid? Or uninformed?
Les _________________ "Let's make noise for peace." - Kijjaz |
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Grumble
Joined: Nov 23, 2015 Posts: 1294 Location: Netherlands
Audio files: 30
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Posted: Wed Dec 28, 2016 1:17 am Post subject:
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THIS is what I use as generator for sine, triangle and pulse generation, and sometimes as programmable clock generator e.g. for the filters I'm using in my diy synth.
These are very accurate to program in terms of frequency, very stable (since they are crystal controlled) wich is not always a good thing, because especially with sound you may want to have some beat to make it sound more alive, and if I want that I have to add it afterwards. |
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Grumble
Joined: Nov 23, 2015 Posts: 1294 Location: Netherlands
Audio files: 30
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Posted: Wed Dec 28, 2016 1:36 am Post subject:
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About measurements:
An analog scope is probably the least accurate instrument if you would want to measure amplitude, if you wat a accurate measurement for amplitudes, you need to have a digital oscilloscope, well at least it looks like it but....
The digital scopes in the diy segment all have an 8 bit adc, so only 256 values to measure a voltage (there are ways to improve on that but that would be too much to explain...)
Plus waht a digital scope can do what an analog can't is (the magig word in all of this:) AVERAGING!
And because of averaging the measurements of frequency seems to be so accurate. |
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Inventor
Stream Operator
Joined: Oct 13, 2007 Posts: 6221 Location: near Austin, Tx, USA
Audio files: 267
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Grumble
Joined: Nov 23, 2015 Posts: 1294 Location: Netherlands
Audio files: 30
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Posted: Wed Dec 28, 2016 2:00 am Post subject:
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To me this ^^^^ is simple |
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Inventor
Stream Operator
Joined: Oct 13, 2007 Posts: 6221 Location: near Austin, Tx, USA
Audio files: 267
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Posted: Wed Dec 28, 2016 3:58 am Post subject:
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Grumble wrote: | To me this ^^^^ is simple |
Yes, simple to use it seems. Fairly complex internals though. Still, very nice!
Les _________________ "Let's make noise for peace." - Kijjaz |
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