Daewoo DV-K*84W Series, Руководство по обслуживанию

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CIRCUIT 9
1)LUMINANCE SIGNAL PROCESSING (RECORD)
The input signal through FBC is reduced 6dB of its level and then the pure luminance signal is obtained by LOW-PASS
FILTER.
In YNR(Luminance Noise Reduction) circuit,the noise is eliminated using the original signal and 1H delayed signal.
The detail enhancer enhances overall high-frequency response, so an object with fine lines can be seen more clearly
during playback.
The nonliner Emphasis and Main Emphasis can minimize the triangular noise susceptible to frequency modulation.
The FM-modulated luminance signal is supplied to PRE-AMP through RECORD EQ for compensating the high frequency
response related to HEAD characteristic, where it RECORD EQ characteristic is determined by LSB 1-4bits of Group 4.
2)CHRONOMINANCE SIGNAL PROCESSING (RECORD)
The pure chrominance signal is obtained by BPF1(fsc :4.43MHz or 3.58MHz) through FBC then is supplied to ACC AMP.
The gain of ACC AMP is controlled by DC voltage at 13th pin.
The ACC AMP OUTPUT is input to MAIN CONVERTER and the main converter down-converts the chromiance signal to
627 or 629KHz.
The down-converted signal is again filtered by the COLOR LOW PASS FILTER, so the pure chrominance components is
maintained.
Meanwhile, the burst level of the ACC AMP output signal is detected by the burst gate and it determines the activation of
color killer.
The final signal through color killer is supplied to PRE-AMP IC10th pin after passing 14th pin.
18
25
40 7
26
FBC
1H DELAY
(LC89978M)
PRE-AMP 9th PIN
1/2 LPF YNR BUFFER
DETAIL
ENHANCER
N.L.
EMPHASIS
MAIN
EMPHASIS
CLAMP
FM MOD REC EQ
REC EQ
5 42
14
13
FBC BPF1 C-LPF KIL PRE-AMP 10th PIN ACC
AMP
REC
DET REC
BGA
MAIN
CONV
FIG.2 Luminance Signal Processing (RECORD)
FIG.3 Chrominance Signal Processing (RECORD)