Casio CZ-1 Service Manual And Spare Parts List page 112

21-2.
Function of Each Block
Analog switch
(TC40538P)
Filter
A
Compressor
Three-Phase
LFOs
VCOs
BBOs
Filter
B
Expander
Determines whether
or
not
passing
melody
signal
through
Stereo
Chorus
circuits. (Controlled
by CPU)
As
the
BBD
does not
pass signals
which exceed 20KHz,
this
block
is
a
low-pass
filter
whose
cutoff frequency
is
20KHz.
In
accordance with input
signal
level,
this
block controls the amplitude.
When
the input
signal
is
small,
the
circuit amplifies the signal
whereas
the amplitude
becomes
smaller
when
the input
is
a
large-level
waveform.
The
block
is
used
for
reducing the
noise.
Generates low-frequency
triangle signals
of
0.56Hz and
7.14Hz.
The
three outputs differ
120
degrees
in
phase.
Voltage Controlled
Oscillator
which
generates the clock pulses for the
BBOs. Their
oscillation
frequencies vary
in
accordance with the input
voltage
level.
Bucket Brigade Device. Stereo chorus
effect
is
given
by
delaying the
right
or the
left
sound.
Since the output
signal
of the
BBD
carries a noise caused
by
clock
pulses,
the
filter
removes the
noise.
Functions contrary to the Compressor. This
circuit
is
also used for
reducing the
noise.
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