[sdiy] SAW core VCO flyback time

[mskala at ansuz.sooke.bc.ca]

On Tue, 30 Aug 2016, Richie Burnett wrote:
> BTW, I think it's fascinating how the analogue designers strive to achieve
> perfection in the form of "instantaneous" sawtooth resets, low-distortion
> sinewaves, and symmetrical triangle waveforms without the little nipple at the

I was holding off on saying it, but if you're serious about analog design,
do you even *want* a super-fast reset?  It seems to me prioritizing that
is going to force you to use wider-bandwidth op amps everywhere the signal
is going; think harder about stability; think harder about EMI (both
radiated and conducted into the power supply); and it's all going to be
wasted anyway once someone runs it through the average audio patch cable
that attenuates such frequencies.  I think if you're generating an audio
sawtooth wave with significant energy above 100kHz (and probably lower)
then your design may not be the best possible for its purpose.

If reset time has an impact on tracking then maybe you want it to be
shorter internally than what you will present at the final output; but
there *is* still a tradeoff.  Overall I think it usually isn't difficult
to make the reset time shorter than optimal, and then a contest of "who
has the shortest reset time?" is a bit silly.

-- 
Matthew Skala
mskala at ansuz.sooke.bc.ca                 People before principles.
http://ansuz.sooke.bc.ca/