1) LUMINANCE SIGNAL PR OCESSING (RECORD)
FBC1/2LPFYNR25400nS26CLAMPDETAIL
DELAY FILTERENHANCER
1H DELAY542
740CLAMP
(LC89977M)
PRE-AMP 9th PIN18REC EQFM MODMAINN.L.
EMPHASISEMPHASIS
FIG.2 Luminance Signal Processing (RECORD)
The input signal through FBC is reduced a half(-6dB) of its level and then the pure luminance signal is obtained by
LPF. In YNR(luminance noise reduction) circuit, noise is eliminated using the original signal and the 1H delayed
signal.
The DETAIL ENHANCER enhances the overall high-frequency response, so an object with fine lines (such as a lawn,
hair etc.) can be seen more clearly during PLAYBA CK.
The NONLINEAR EMPHASIS and MAIN EMPHASIS can minimize the triangular noise susceptible to frequency
modulation.
The luminance signal is FM-modulated and then is supplied to RECORD EQUALIZER for compensating the high
frequency response related to HEAD characteristic, where its RECORD EQ is determined by the GROUP 4, LSB 1-4
2
bits of IC serial control.
2) CHROMINANCE SIGNAL PR OCESSING (RECORD)
FBCBPF 1ACCMAINC-LPFKIL14PRE-AMP 10th PIN
AMPCONV
13
RECREC
DETBGA
FIG.3 Chrominance Signal Processing (RECORD)
The pure chrominance signal is obtained by BPF1 (fsc : 4.43MHz), which filters the input signal through FBC.
The gain of ACC AMP is controlled by the DC voltage at 13th pin.
The main converter down-converts the chrominance signal with signal carrier of 4.43MHz to the signal with signal
carrier of 627KHz.
The down-converted signal is again filtered by the LPF, so the pure chrominance component 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.
CIRCUIT9 |
ACEC
