Daewoo DV-K*84W Series, Service Manual

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2. PAL AUDIO FLOW (Two carrier) (Hi-Fi only model)
The FM sound intercarrier signal passing through the 5.5MHz/5.74MHz (DK: 6.5MHz) sound BPF is fed to a limiter
amplifier before it is demodulate. This gives high sensitivity and AM suppression. The limiter amplifier consists of
seven internal AC-coupled stages, minimizing the DC offset. The FM-PLL demodulator consists of an RC-oscillator,
loop filter and phase detector. The oscillator frequency is locked on to the FM intercarrier signal from the limiter
amplifier. As a result of this locking, the RC-oscillator is frequency modulated. The modulating signal voltage is used to
control the oscillator frequency using this technique, the FM-PLL works as a FM demodulator. The audio signal(AF1:
L+R/2, AF2:R+pilot(AM)) passing through the stereo/dual sound processor. Its identification ensures safe operation by
using internal digital PLL technique with extremely small bandwidth, synchronous detection and digital
integration(switching the maximum 2.6s; identification concerning the main functions).
The audio signal(L, R) is amplified and coming out of the stereo/digital sound processor.
CIRCUIT 13
VIDEO DET
& DEMOD
VIDEO BLOCK
intercarrier
SOUND
BPF
LIMITER
AMP
FM PLL-
DEMOD.
AF
AMP
FM PLL-
DEMOD.
DIGITAL
INTEGRATOR
AUDIO OUT (L)
AUDIO OUT (R)
STEREO(LOW)
DUAL(LOW)