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<DIV><FONT face=Arial size=2>This is essentially the phase distortion algorithm
used in the Casio CZ synths. I think that it used a sine wavetable indexed by a
ramp oscillator, where a "kink" could be placed in the ramp, such that the first
half of the sine wave was indexed at a different rate than the second half.
Harry Bissell's saw/triangle morph through a sine waveshaper would work just as
well. </FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Sean Costello</FONT></DIV>
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style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=controlvoltage@gmail.com
href="mailto:controlvoltage@gmail.com">Amos</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=synth-diy@dropmix.xs4all.nl
href="mailto:synth-diy@dropmix.xs4all.nl">Synth DIY</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Wednesday, January 18, 2006 7:59
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> [sdiy] Sine width
modulation?</DIV>
<DIV><BR></DIV>Apologies if this has been covered before, but I am
curious...<BR><BR>Is it practical or musically useful to investigate per-cycle
sinewave FM, a la pulse-width modulation?<BR>I envisioned an FM process such
that for example, the rising/positive portion of each sinewave cycle is at a
higher frequency while the falling/negative portion is at a lower
frequency. (or vice-versa I suppose, for >50% duty cycle)<BR>Would
this still be considered sinusoidal? Does it sound like anything other
than a pulse waveform with very-low-cutoff lowpass filter applied?<BR><BR>I
feel like this is perhaps an ignorant question, but I would be grateful for
any replies on the topic.<BR><BR>Thanks!<BR><BR>[for implementation, I was
thinking that a Pulse wave at the same fundamental frequency as the sine to be
modulated could be used, with the pulse duration corresponding to the amount
of frequency offset for the positive portion of the sinewave. The means
by which the one should influence the other (specifically how to create
positive and negative half-waves of differing frequency without artifacts) is
still unclear to me...]<BR></BLOCKQUOTE></BODY></HTML>