Sony SEQ-555ES - Page 10

SEQ-555ES
to equalizer circuit
Sg switch
LINE IN
AUX,
AUX,
from equalizer
circuit
TAPE2
TAPE]
to LINE OUT
REC OUT2
REC OUT1
F, and F3 are interlocked.
EQUALIZER CIRCUIT
ICios
Ry20 13k
Crip 220P
controlled by
microcomputer
Cros
CX-7976
resonance
circuit
63H2
resonance
circuit
31.5Hz
The equalizer circuit is structured as shown in the
above diagram, and actually, four IC’s are connected
parallel to ICj93 and determine the frequencies.
These IC’s are controlled by microcomputer.
In the example above, many switches and resistors
are connected inside ICj9g, and because it is con-
nected to the resonance circuits via these resistors,
and the NF circuit is connected to these resonance
circuits when it is on the UP side, the frequency
component output gain becomes high. When DOWN,
these resonance circuits connect to the attenuation
circuit, so the frequency component gain drops.
ICiog is controlled by microcomputer, and depending
on the data sent from the microcomputer, can
control only Q; or Qz, or both.
The equalizer frequency is controlled by these combi-
nations.
+6dB or +12dB switching is done by ICj97. When
ICjo7 internal switch is off, it is +12dB, and +6dB
when on.
CX-7976
Features: This is a 2 channel independent variable
2dB step electronic volume for low dis-
tortion equalizer, containing two circuits
which can obtain +12dB attentuation.
Control is done by 11 bit serial data from
a microcomputer, etc.
Functions:
Qi. (@, @, &, @ ) These pins are connected to L
and R_ channel resonance
circuits.
UP (@, @ ) Connected to op amp invert-
ed input.
DOWN (@, @) Connected to op amp non-
inverted input.
Serial data bits 9, 10 and 11
are all selected at the same
time as pins CS,,2,3 level.
“<Q” = Vss
“1”? = OPEN or Voi
CSi,2,3 (©, ©, @)
VDL (@) Power supply (5V higher than
Vss).
Vss (@) Power supply (-14V).
CLOCK ( @) Clock signal input pin.
Data (dad) Serial data input pin.
Strobe (@) Latches data taken into the
IC at signal rise.
Lyref (4) Sets control signal (clock,
data, strobe) input level.
Vpp (@) Power supply (+14V).
The 11 bit serial control data is input to the IC from
the MSB (most significant bit).
Data is taken into the IC shift register at clock signal
rise.
After data is taken in, the clock signal is stopped,
and the strobe signal rises. The strobe signal transmits
the data to the latch, and the data contents determine
which switch is turned on or off.