Pioneer KEX-900 Service Manual page 22

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TesI77P Louoness
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Fig. 8
© Loudness function
The TC9177P has tap for loudness. When bit 3 of the data
is made to '1, " loudness switch LS1 will turn ON, LS2
will turn OFF, and the —20 dB tap is output to loudness-1
and loudness-2 terminals,
With the loudness-1 and foudness-2 terminals having a
high-low band boost circuit, loudness can be controlled
below —20 dB.
The attenuator section consists of a diffused resistor array
and an analog switch. Attenuator 1 can attenuate 0 to
70 dB at 10 dB step, and attenuator 2 can attenuate 0 to
8 dB at 2 GB step, for a total attenuation of 0 to 76 dB at
2 dB step.
ouT2
Attenuator 2
A-GND l Attenuator 1
Fig. 9
When bit 3 of the data is made to '0, " loudness switch
LS1 will go OFF, and LS2 will go ON. Loudness wil! go
OFF without high-low band boost circuit operation.
bee ennnnpanne
LOUONESS~1
LOUONESS-2
25
-30dB
-4008
Fig. 10