<html><head></head><body>You run into the same problem trying to do pitch
to voltage conversion. TomG has a pitch to voltage converter on his site
that I seem to remember uses a downslope detector to detect the true fundamental
(his site seems to be down right now).<br>
There's also an Electronotes article EN#136 that discusses using a Hilbert
Transform: take the signal and the 90 degree phase delay network, square
both of them with multipliers, then sum the squares. It supposedly removes
harmonics and strengthens the fundamental, improving the multiple zero crossing
problem of complex signals. Then he runs it into a downslope detector to
extract the true fundamental.<br>
I plan on playing with it (sometime - you know how it goes) because I want
to build a pitch to CV I can use with voice or guitar.<br>
<br>
harry wrote:<br>
<blockquote type="cite" cite="mid:3A60D3B5.488252EB@prodigy.net"><pre wrap="">Aahhh....<br><br>Nice try. Probably will not work.<br><br>Problem... How do you decide the "waveform" crossing points. I'm thinking of<br>a Guitar wave... which is a bastard ! It may cross zero more times than you<br>like.<br>Tracking the peaks will not work either.<br><br>DDL pitch shifters do exactly this. If they have very short delays... the<br>glitches in<br>the waveform are severe. If you can wait a week... you could make a really long<br>delay.<br><br>You should tape record the whole thing... then edit out every other cycle, then<br>play<br>at 1/2 speed...<br><br>Or just hire a Psychic to set the unit properly for the "next" note you are<br>about to<br>play....<br><br>H^) harry<br><br>Magnus Danielson wrote:<br><br></pre>
<blockquote type="cite"><pre wrap="">From: harry <a class="moz-txt-link-rfc2396E" href="mailto:harrybissell@prodigy.net"><harrybissell@prodigy.net></a><br>Subject: Re: modules with different tubes?<br>Date: Sat, 13 Jan 2001 11:44:39 -0500<br><br></pre><blockquote type="cite"><pre wrap="">If ANYONE gets a really good octave divider for guitar, tube or otherwise,<br>LET ME KNOW !!!<br><br>I'll build it even if it is TUBES.... ;^)<br><br>(of course I doubt anyone will ....)<br></pre></blockquote><pre wrap="">Hmm... I just came up with an obscure idea using a pair of BBDs, but<br>I am sure you're not interested ;)<br><br>Theory: Do frequency tracking, fetch an overtone to sample in a full<br>BBD, play it out at half clock-rate. Alternate BBD so that one is in<br>"record" and the other is in "play" mode. Since they track frequency<br>one snaps a waveform and plays that pitched down but on the same<br>boundary. Simple? Heck no! Obscure? You bet!<br><br>Reason for conception? Annoyment and ammusement of Harry! ;)<br><br>There are loads of problems with this strategy thought. Can we learn<br>anything?<br><br>Cheers,<br>Magnus<br></pre></blockquote>
</blockquote>
<br>
<pre class="moz-signature">--
Scott Bernardi
<a class="moz-txt-link-abbreviated" href="mailto:sbernardi@home.net">sbernardi@home.net</a></pre>
<br>
</body></html>