Sony SEQ-555ES - Acoustic Compensation

connected to
resonance circuit Q
1
UP
Q } connected to
resonance circuit
Q,
DOWN
Lyvref
Strobe
Data
CLOCK
Control Data Structure
ll ol 5 4 3 2 1
1 |
0 9 8 7 6
esfesfes[e[-[e]: [ mae
position position Bi position ia
6 5 4321
no change no change | 0 0 —12dB} 0110
Qi 01 —10 0101
Q2 10 —8 0100
Q+Q: [11 —6
—4 0010
~—2 0001
0 0000
+ 2 ool
+4 1010
+6 1011
+ 8 1100
+10 1101
+12 1110
input =>
SEQ-555ES
AUTOMATIC ACOUSTIC COMPENSATION
Pink noise is output from the oscillator inside this
set and radiates from the speaker. These signals are
input at the microphone, divided into 10 bands,
measured and analyzed, then equalization is applied
to flatten frequency response.
The signal input from the MIC jack is amplified at
the ICy9; mic amp circuit. (The frequency response
is corrected at the same time.)
The amplified signal is applied to ICs;g. The ICs)
output signal is applied to the frequency filter cir-
cuits, then is rectified at the rectification circuit,
passes the multiplexer circuit and is digitalized at the
A/D converter, and is memorized in the RAM by
microcomputer B.
The equalizer is controlled by this memorized con-
tent to flatten frequency response.
FILTER CIRCUIT
IC, rectification circuit
In the circuit above, the RLC resonance circuit is
formed by Q1, C2, C3, R2 and R3. IC,, Cy, Ri and
the resonance circuit form a band pass filter.
C2, C3, Ro and R3 determine the center frequency.
a 1
10 pe J RIRICIC
After passing the filter circuit, it is converted to DC
voltage by the rectification circuit. This DC voltage
is applied to the A/D converter via the multiplexer.