cxa2561q Sony Electronics, cxa2561q Datasheet - Page 14

• Manufacturer Part Number: cxa2561q
• Description: Dolby B-c Type Noise Reduction System With Playback Equalizer Amplifier
• Manufacturer: Sony Electronics

4. Music sensor
(1) Adjustment of music signal detection level
(2) Low-frequency cut-off adjustment of music sensor
(3) High-frequency cut-off adjustment of music sensor
(4) Response time adjustment
Adjustment the exrernal resistors R7 and R8 to adjust the music signal interval detection level.
The signal detection level v1 and no signal detection level v2 are expressed by the following equations.
Adjust the external resistors R7, R8 and the external capacitors C3, C4 to adjust the low-frequency cut-off.
The low-frequency cut-off is expressed by the following equation.
Adjust the capacitor C2 to MSLPF (Pin 10) to adjust the high-frequency cut-off. The high-frequency
cut-off is expressed by the following equation.
The high-frequency cut-off is approximately 25kHz when MSLPF is left open.
Adjust the external resistor R9 and the external capacitor C5 to adjust the response time.
The response time for signal detection depends on the internal resister R6 and the external capacitor C5.
The response time for no signal detection depends on the external resistor R9 and the external capacitor C5.
v1 = –39 + 20log (39k/Rext) [dBm] Rext: R7 or R8
v2 = v1 – 2 [dBm]
fc1 = 1/ (2 · Cext · Rext) Cex, Rext: C3, R7 or C4, R8
fc2 = 1/ (2 · (64p + C2) · 100k)
10k
10k
R2
R1
TAPEIN1
TAPEIN2
1
1
VGS
AMP1
127k
D2
D1
R3
100k
R4
64p
C1
Fig. 5. Music sensor block diagram
MSLPF
C2
AMP2
G1FB
Vcc
– 14 –
5
C3
R7
Full-
wave
rectifier
Q1
G2FB
C4
R8
R5A
R5B
29k
10k
Smoother
MSTC
R6
1k
R9
0.775V for
signal detection
0.616V for no
signal detection
C5
AMP3
MSOUT
DVcc
R10
CXA2561Q