Doepfer A-191 Shepard Generator/16xMIDI-CV Interface (no longer available) - Manual (Page 12)

A-191 MCV 16 System A - 100 doepfer
12
5. Shepard generator
5.1 Basics
A Shepard generator is a modulation oscillator,
which produces various phase inversions of triangle
and sawtooth waveforms at its outputs.
The way the Shepard generator is set up produces
various psycho-acoustic phenomena, such as the
‘barber-pole’ effect - seemingly never-ending upward
or downward spirals of pitch, filter settings, phasing,
and stereo or quadraphonic sound-stage panning (see
chapter 5.3, User examples).
The triangle wave signal is sent via outputs T 0 to T
315, and the sawtooth wave signal is sent via out-
puts S 0 to S 315, (where the numbers refer to the
phase displacement for each output in degrees).
Fig. 5 shows this, but with only every other output
included, for the sake of clarity. T
LFO
is the time the
internal LFOs take to complete one cycle.
The Shepard mode - the direction of the sawtooth
waveform generated - is selectable. Fig. 5 shows the
mode with a sawtooth waveform.
Fig. 5: Shepard generator output signals (half shown)
T
S 0
S 90
S 180
S 270
T 0
T 90
T 180
T 270
LFO
T
LFO