CXA2560 View Datasheet(PDF) - Sony Semiconductor

Part Name

Description

Manufacturer

CXA2560

Dolby∗ B Type Noise Reduction System with Playback Equalizer Amplifier

Sony Semiconductor 

CXA2560Q

4. Music sensor

TAPEIN2

D1

×1

R2

10k

D2

R3

127k

AMP1

R1

10k

VGS

×1

R4

100k

C1

64p

DVcc

Vcc

AMP2

× 5 Full-

wave

rectifier

Q1

Smoother

R5A

29k R6

1k

R5B

10k

AMP3

0.775V for

signal detection

0.616V for no

signal detection

R10

MSOUT

TAPEIN1

MSLPF

C2

G1FB

C3

G2FB

C4

R7

R8

MSTC

R9

C5

Fig. 5. Music sensor block diagram

(1) Adjustment of music signal detection level

Adjust the external 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.

v1 = –39 + 20 log (39k/Rext) [dBm] Rext: R7 or R8

v2 = v1 – 2 [dBm]

(2) Low-frequency cut-off adjustment of music sensor

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.

fc1 = 1/ (2π · Cext · Rext)

Cext, Rext: C3, R7 or C4, R8

(3) High-frequency cut-off adjustment of music sensor

Adjust the external capacitor C2 to MSLPF (Pin 10) to adjust the high-frequency cut-off. The high-frequency

cut-off is expressed by the following equation.

fc2 = 1/ (2π · (64p + C2) · 100k)

The high-frequency cut-off is approximately 25kHz when MSLPF is left open .

(4) Response time adjustment

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 resistor R6 and the external capacitor C5.

The response time for no signal detection depends on the external resistor R9 and the external capacitor

C5.

– 14 –

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