Harmonics question

[Ian Fritz]

Of all the work I did on novel waveshapers, the double-pulse waveform
generators (DPWGs) were far and away my favorite circuits. There were
actually several different versions, only one of which went to EN. 

The latest incarnation is a totally voltage-controlled module in my
hybrid synth. It has two pulses of equal width. The first has positive
polarity and the second is switchable to either positive or negative
polarity. 

The pulse widths are under voltage control as is the position of the
second pulse. This allows "pulse position modulation" as well as the
more familiar pulse width modulation. I use this module all the time,
but more for the wide variety of timbres it can produce than for the
sweeps.

  Ian



Stopp,Gene wrote:
> 

> Speaking of interesting harmonic sweeps, this reminds me of a pulse
> shaper that I came up with a while back that produced really interesting
> sounds. It was an expansion of a circuit in Electronotes (the "Dual
> Pulse Waveform Shaper") which used four comparators to create a
> symmetric-around-ground pulse width modulated waveform. If you feed it
> with a triangle wave and sweep the PWM input, you will get a PWM'ed
> sound with only odd harmonics (i.e. satisfying the mirror-image
> requirements). I'd forgotten about this - now I want to build one again!
> 
>  - Gene
>