Moog Satellite Service Manual

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at B21 3 s zero, R31 is open and current flows through R170-171
to greatly speed u£ the decay slope. The "sustain" switch connects
B21 to +9~v;hen it is down, and connects it to the trigger line
when it is up. As a result, the tone is rapidly squelched when
the "sustain" tab is up and the keys are released.
As noted above, the keyboard pitch voltage controls both
attack c.nd decay times through R199 and R198 respectively. These
times change by a factor of approximately 2.5 over the complete
keyboard range.
The filter contour generator contains most of the features
of the amplitude contour generator. Q15 of the filter contour
generator*corresponds to Q35 of the amplitude contour generator,
Q13 to Q34, and Q12 to Q36. An additional feature of the
contour-initiating circuitry is the coupling in of trigger pulses
from the modulating oscillator through R36 and.R90 to produce
repeated filter contours (Fig. 5). The "filter contour choice"
control current that comes from the matrix row #11 through R 88
and R91 determines whether the filter contour will rise and then
immediately fall, or fall only upon release of all keys. Q9-10
of the filter contour generator corresponds to Q26-27 of the
amplitude contour generator. The current from Q10 determines
the decay time of the contour. Similarly, IC14 corresponds to
IC18, Q18-19 corresponds to Q28-29, and Q16 correxponds to Q30.
R95 and R10I couple the keyboard voltage to the attack and
decay control circuits. Finally, the voltag- applied to B18
from the contour potentiometer simultaneously varies the attack
and decay rimes of the filter contour. Q22 and Q23 are routing
switches; only one is on at a time. The "filter contour routing"
control current from matrix row #5 determines whether- Q17 is
open or saturated. . If Q17 is open, then Q21 is also open, and
Q24 is saturated. Thus, Q22 is biased on and Q23 is biased off,
and the contour is routed to the low pass filter. On the other
hand, if Q17 is saturated, Q2 3 is biased on and the contour is
routed .to the center frequency control input of the bandpass filter.
DESCRIPTION OF CIRCUITRY ON SMALL BOARD
The raw power supply and modulating oscillator are mounted
on the smaller circuit board, along with the seven slide
potentiometers. Refer to drawing 08-004 for the schematic of
this board. The raw supply is completely conventional. The
nominal total load drawn from each of the raw voltages is 45
ir.illiamperes.' The modulating oscillator consists of ICl, IC2,
and associated components. IC2 is an integrater and ICl is a
Schmitt trigger. The waverform at the output of IC2 is triangular
and the waveform at the output of ICl is square. The output of
ICl is used to drive Ql in and out- of saturation. Thus, the
voltage at the square wave output (pin 12 ) is a square wave with
a peak amplitude of precisely -9 volts. The trigger output
(pin 10 ) is a positive pulse which occurs when the square wave *
switch.es from negative to positive. The current which supplies
the integrater, and therefore the oscillator frequency, is
varied by means of RIO. The frequency range is 1-50 Hz.

Moog Satellite Specifications

General

Brand	Moog
Model	Satellite
Category	Synthesizer
Language	English