JVC CA-C55BK - IC Descriptions - Echo Circuit and Motor Driver; BA77258 (IC990) and LB1641 (IC451~454) Details

DX-C55BK
B BA77258 (1C990) :Echo circuit
Internal Black Diagram
Terminal Description
Symbol Function
| LINE OUT Line output
LINE IN Line input
Not used
Determines echo level. The echo circuit is off when 1 volt is added. The echo level
varies according to the voltage from 2 volts to 9 volts.
Analog GND
LOOP GAIN CTRL | Loop gain control terminal. The gain baries according to the voltage from 2 volts to 9
volts.
Detection terminal for expand circuit
Determines the atack and recovery time of expand circuit
Buffer output (Expand circuit side)
Buffer input (Expand circuit side)
Delay buffer output
Delay buffer input
Buffer output (Compress circuit side)
Buffer input (Compress circuit side)
Compress circuit output
Determines the atack and recovery time of compress circuit
Detection terminal for compress circuit
A capacitor is connected for ripple ellimination filter
Power supply
Not used
Mic amp output
Mic amp input
39-CV (IC508) : Motor driver
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Function
GND Pi IN4 vcci P2
OUT! VZ IN2. VCC2) ~OUT2
«:Hig impedance
2-4 (No.20474)