Kurzweil K2661 Musician's Manual page 547

Pulse Width Modulation (PWM)
0
1
0.8
0.6
0.4
0.2
0
-0.2
-0.4
-0.6
-0.8
-1
0
1
0.8
0.6
0.4
0.2
0
-0.2
-0.4
-0.6
-0.8
-1
Pulse width modulation can produce some classic synth sounds, and can break new sonic
ground as well. Its operation is very simple; it adds an oscillating DC offset to the input signal
(shifts it toward positive or negative full scale). Unless it causes the signal to clip, it won't have
much effect on the signal. It's designed to be followed by DIST, with the Adjust parameter for
DIST set to a fairly high level. The DIST function will drive all positive elements of the signal
toward positive full scale, and negative elements toward negative full scale. The result is a
rectangular wave with a width that varies according to the Adjust level of PWM.
PWM won't affect a square wave input. Sine and triangle waves will produce familiar PWM
sounds. More complicated waveforms will result in discontinuous rectangular waveforms.
You can also follow a PWM algorithm block with SHAPER, since SHAPER's output is affected
by the DC level of the signal.
Time in milliseconds
50 100 150 200
SINE followed
by PWM
Time in milliseconds
50 100 150 200
SINE ->
PWM->
DIST
70
250 300 350 400
70
PWM Adjust
30
from 30 to 70
250 300 350 400
30
DIST gain = 0;
PWM Adjust
from 30 to 70
DSP Functions
The DSP Functions
450 500
450 500
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