Moog System 15 Instruction Manual page 9

B. USING THE KEYBOARD TO DETERMINE PITCH
1. Patch from the RECTANGULAR output of a 921B OSCILLATOR to a SIGNAL INPUT
on the 902 VOLTAGE CONTROLLED AMPLIFIER, and from a SIGNAL OUTPUT on a
902 VOLTAGE CONTROLLED AMPLIFIER to TRUNK LINE 1. A tone should be heard.
The signal generated in the 921B is being amplified and sent to the trunk line. To control vol-
ume, vary the FIXED CONTROL VOLTAGE control on the 902.
2. Vary the FREQUENCY control and the RANGE switch on the 921B. These controls
change the frequency (pitch) of the tone.
3. Vary the FREQUENCY control on the 921A. This control changes the frequencies of both
921B OSCILLATORS simultaneously. Flip the SEMITONE-OCTAVE switch and note that
the effect of the FREQUENCY control changes accordingly.
4. Vary the WIDTH OF RECTANGULAR WAVE control on the 921A. Note the change in
tone color which accompanies waveform width change. This control only affects the RECT-
ANGULAR outputs on the 921B's.
5. Patch from the CONTROL VOLTAGE 1 output of the CONTROLLER OUTPUTS to one
of the FREQUENCY control inputs on the 921A. Play the keyboard. The keyboard pitch con-
trol signal depends on the last key depressed. It is applied to the 921B through the 921A,
thereby controlling the pitch of the tone. Note that the SCALE control on the keyboard varies
the size of the intervals, while the RANGE control on the keyboard transposes the pitch. Note
further that the GLIDE control slows down the changes in keyboard pitch voltage when the
GLIDE switch is on.
907A 995
0 0
8'
50
921A 921B 921B 923
MIXER REV
6
904A 902 902
921 911 911
CONTROLLERS TRUNK