[sdiy] VCO reset time

[Ian Fritz]

At 04:44 AM 6/7/2004, Antti Huovilainen wrote:
>On Sun, 6 Jun 2004, Don Tillman wrote:
>
> > The topic is PWM from a triangle vs. PWM from a sawtooth.
>
>Isn't sawtooth based PWM same as triangle PWM that is phase modulated?
>Pulse wave is equal to two sawtooth waves with delay and opposite phases.
>In triangle based PWM you phase modulate both saws in opposite directions,
>while in sawtooth based PWM you only modulate one saw. Thus to me it seems
>that sawtooth PWM is same as PWM but in addition to changing the pulse
>width (as with triPWM) you also change the midpoint of the pulse
>(same as phase modulating the triPWM).
>
>Antti

Good way to look at it!

And if you think in terms of the wave propagating through the air, the 
extra phase modulation gives you a Doppler shift.  This is, in fact, what 
you hear.  The modulated saw goes up and down in pitch.

   Ian