AW: Re: Pulse width circuit??????
gstopp at fibermux.com
gstopp at fibermux.com
Wed Dec 6 22:08:29 CET 1995
You got the idea... however no matter what chip I try in the future
I'll be looking at the scope as the second-to-the-last test. No matter
what the numbers are on the spec sheet, I want to look at the square
wave on the scope and see a pair of dashed lines going from left to
right, complimentary to each other, perfectly flat, with nothing in
between them, at all audio frequencies, into a 1K load to ground. No
ringing, overshoot, slews, slopes, asymmetries, or artifacts. If I see
that I'm happy.
Ah heck another lab thing to do.
- Gene
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Subject: Re: AW: Re: Pulse width circuit??????
Author: ftom at netcom.com (Tom May) at ccrelayout
Date: 12/6/95 1:47 PM
My turn to apologize for extreme techno-babble. Maybe this thread
should park itself on synth-diy?
Doesn't ECL have the same problem with different rise and fall times?
It's either that, or some kind of under or overshoot. The ECL
waveforms I remember were functional but not very pretty. (I realize
you didn't actually say "ECL", but "similar to ECL".)
Anyway, if my Fourier-series calculations are correct, a 20Hz +/- 15V
square wave slewing at 8V/us has harmonics out to the 6,666th at
133+kHz, give or take a few thousand harmonics, which should be enough
for anybody. Assuming the Fourier series is simply truncated after the
6,666th harmonic, which is not true; if it were, you'd see the 9%
overshoot associated with the Gibbs phenomenon on a scope.
Sounds like if anything is going to be a problem, it's the corners.
fTom.
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