D-61508-98-C

ELECTRIC

MITSUBISHI

( /22)

THE ELECTRIC VOLUME of BUILD-IN NON FADER VOLUME with TONE CONTROL

MITSUBISHI SOUND PROCESSOR ICs

M61508FP

ZERO-CROSSING DETECTION CIRCUIT

In the conventional Serial Data Control Type Volume, Analog SW inside switches over

simultaneously with Latch Condition Detector. And the operation completes.

In this case the changing noise occurs at the time of Latch Condition Detector, the

Analog SW switches over (Zero-cross Detector Strobe occurs) in the moment that the

Analog Signal cross Signal Ground (1/2VCC).

Latch Conditions

D32

D33

D34

Noise Factor when

Signal is present

Audio Signal

Signal GND(1/2Vcc)

Latch Conditions

D32

D33

D34

Signal GND (1/2Vcc)

Analog SW changing

Zero-cross Detector Strobe

(Form signal from inside IC)

Other,In the case of Audio Signal isn't inputted (No signal),even if only Zero-cross

Detector Circuit detects Latch Condition, Analog SW doesn't switch over for the

Audio Signal never cuts Signal Ground (1/2VCC).

The Time Function switches the Analog SW after some time T.

The Timer Time can setting with the Serial Data of 5mS,10mS,15mS,20mS.

CLK

DATA

CLK

DATA

1. Meaning of Zero-Crossing Detection Circuit

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