3038 Waveform Generator HELP!

Christopher List Christopher_List at sonymusic.com
Tue Feb 20 11:16:09 CET 1996


> I ordered some of those Harris 8038 precision waveform generator VCO chips. I
> built some test circuits and found that it worked quite nicely except for the

>The
> datasheets were extremly open ended and i have been having trouble designing
> a circuit that fits my needs (i.e. signals from about .01 hz  to 20 mhz, duty
> cycle from 1%/99% to 99&/1% or there abouts, as well as a standard 1 volt per
> octave VCO operation) I would be grateful if someone could help with precise
> component valuesand circuit design.

Wow! 20Mhz! - that's a 1:200,000,000 sweep range! - I think we know what you 
mean, though :).

Yes, I too have had some trouble going from data sheet to useful LFO with this 
bugger. I think you will be hard pressed to get an exponential converter to 
drive it accurately. I am just looking for linear voltage control in the .01 - 
100hz range and haven't been able to do it. Seems like the voltage sweep 
circuit in the data sheet can't go that low - even with much bigger caps.

Anybody ever make a good VC-LFO with this thing. Maybe I'll go back to it, I 
got very frustrated very quickly and just gave up. It's easy enough to get a 
VCO out of it, but getting the sweep range and frequncies for it is a drag and 
the data sheet isn't much help...

- CL
(No TV)



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