25
7. Mute Signal Block
Mute Signal Block
IC1201
SYSTEM CONTROL
114
85
31
ERROR
SURROUND
MUTE
0V
NORMAL
SOFT
MUTE
R1241 R1247
10K
Ω
10K
Ω
R1218
10K
Ω
MUTE
Q1507
QV S.W. BOARD
C1214
2200pf
Q1204
0V
NORMAL
DIGITAL
AUDIO
I/F
RECEIVER
IC1101
34
ERROR
MUTE
R1110
0V
NORMAL
1K
Ω
AUDIO
CODEC
IC1503
3
S MUTE
FIGURE 7-1 - MUTE SIGNAL BLOCK
4A124
1/21/02
Q1203
NOT USED ON STR-DE845
Circuit Description
NOTE:
Reference figure 7-1 for the following circuit description.
The receiver is muted by one of three ways: 1) Surround Mute (front panel button); 2) Error Mute (an error in the
digital data input to IC1101) or 3) Soft-Mute (through software in IC1201 system control). All mute lines are at a
low state (0V) in normal operation (active high and are activated during the following actions:
1)
Surround Mute
: Output from IC1201 pin 85.
a) Depression of front panel mute button
b) While switching between inputs
c) While switching between sound fields
d) During power on
2)
Error Mute
: Output from IC1101 pin 34 and then applied to IC1201 pin 114.
a) If an error is detected in the data to IC1101 (input must be S/P DIF format)
b) If there is no connection to the optical or coaxial inputs (the device must also be powered on)
c) If the analog input is selected
d) During power ON
3)
Soft Mute
: Output from IC1201 pin 31.
Not functional on this Model (Continuous LOW state).
The active high from the Surround mute and Error mute lines is applied to the base circuits of Q1204 and Q1203
respectively. The active high turns the transistors ON, which then applies a low (ground) to the base of Q1507
on the AU SW board and hard mutes the audio outputs.
Содержание STR-DE845
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