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
