PAL/NTSC/SECAM video decoder with adaptive PAL/NTSC comb ...

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This text is here in white to force landscape pages to be rotated correctly when browsing through the pdf in the Acrobat reader.This text is here in _white to force landscape pages to be rotated correctly when browsing through the pdf in the Acrobat reader.This text is here inThis text is here in white to force landscape pages to be rotated correctly when browsing through the pdf in the Acrobat reader. white to force landscape pages to be ... 2000 Mar 15 18 CVBS-IN or CHR-IN CVBS-IN or Y-IN QUADRATURE DEMODULATOR SUBCARRIER GENERATION 1 HUEC LDEL YCOMB SUBCARRIER GENERATION 2 CHROMINANCE INCREMENT DELAY DELAY COMPENSATION LOW-PASS 1 DOWNSAMPLING RTCO QUADRATURE MODULATOR LCBW[2:0] LDEL YCOMB CHROMINANCE INCREMENT DTO-RESET SUBCARRIER INCREMENT GENERATION AND DIVIDER CDTO INCS CSTD[2:0] CHR UV ndbook, full pagewidth SUBTRACTOR INTERPOLATION LOW-PASS 3 LUBW ADAPTIVE COMB FILTER SET_RAW SET_VBI PHASE DEMODULATOR AMPLITUDE DETECTOR BURST GATE ACCUMULATOR LOOP FILTER FCTC ACGC CGAIN[6:0] IDEL[3:0] UV CCOMB YCOMB LDEL BYPS CODE UV LUFI[3:0] CSTD[2:0] YDEL[2:0] LOW-PASS 2 SECAM PROCESSING UV- ADJUSTMENT SECS CHBW CHROMA GAIN CONTROL Fig.9 Chrominance and luminance processing. Y LUMINANCE-PEAKING OR LOW-PASS, Y-DELAY ADJUSTMENT SET_RAW SET_VBI f H /2 switch signal Y/CVBS DBRI[7:0] DCON[7:0] DSAT[7:0] RAWG[7:0] RAWO[7:0] COLO BRIGHTNESS CONTRAST SATURATION CONTROL RAW DATA GAIN AND OFFSET CONTROL UV PAL DELAY LINE SECAM RECOMBINATION SET_RAW SET_VBI SET_RAW SET_VBI DCVF MHB532 Y-OUT/ CVBS OUT UV-OUT HREF-OUT 8.1.3 CHROMINANCE AND LUMINANCE PROCESSING PAL/NTSC/SECAM video decoder with adaptive PAL/NTSC comb filter, VBI-data slicer and high performance scaler SAA7114H Philips Semiconductors Preliminary specification
Philips Semiconductors PAL/NTSC/SECAM video decoder with adaptive PAL/NTSC comb filter, VBI-data slicer and high performance scaler Preliminary specification SAA7114H 8.1.3.1 Chrominance path The 9-bit CVBS or chrominance input signal is fed to the input of a quadrature demodulator, where it is multiplied by two time-multiplexed subcarrier signals from the subcarrier generation block 1 (0° and 90° phase relationship to the demodulator axis). The frequency is dependent on the chosen colour standard. The time-multiplexed output signals of the multipliers are low-pass filtered (low-pass 1). Eight characteristics are programmable via LCWB3 to LCWB0 to achieve the desired bandwidth for the colour difference signals (PAL, NTSC) or the 0° and 90° FM signals (SECAM). The chrominance low-pass 1 characteristic also influences the grade of cross-luminance reduction during horizontal colour transients (large chrominance bandwidth means strong suppression of cross-luminance). If the Y-comb filter is disabled by YCOMB = 0 the filter influences directly the width of the chrominance notch within the luminance path (large chrominance bandwidth means wide chrominance notch resulting to lower luminance bandwidth). The low-pass filtered signals are fed to the adaptive comb filter block. The chrominance components are separated from the luminance via a two line vertical stage (four lines for PAL standards) and a decision logic between the filtered and the non-filtered output signals. This block is bypassed for SECAM signals. The comb filter logic can be enabled independently for the succeeding luminance and chrominance processing by YCOMB (subaddress 09H, bit 6) and/or CCOMB (subaddress 0EH, bit 0). It is always bypassed during VBI or raw data lines programmable by the LCRn registers (subaddresses 41H to 57H), see Section 8.2. The separated UV-components are further processed by a second filter stage (low-pass 2) to modify the chrominance bandwidth without influence to the luminance path. It’s characteristic is controlled by CHBW (subaddress 10H, bit 3). For the complete transfer characteristic of low-passes 1 and 2 see Figs 10 and 11. The SECAM processing (bypassed for QUAM standards) contains the following blocks: • Baseband ‘bell’ filters to reconstruct the amplitude and phase equalized 0° and 90° FM signals • Phase demodulator and differentiator (FM-demodulation) • De-emphasis filter to compensate the pre-emphasized input signal, including frequency offset compensation (DB or DR white carrier values are subtracted from the signal, controlled by the SECAM switch signal). The succeeding chrominance gain control block amplifies or attenuates the UV-signal according to the required ITU 601/656 levels. It is controlled by the output signal from the amplitude detection circuit within the burst processing block. The burst processing block provides the feedback loop of the chrominance PLL and contains: • Burst gate accumulator • Colour identification and killer • Comparison nominal/actual burst amplitude (PAL/NTSC standards only) • Loop filter chrominance gain control (PAL/NTSC standards only) • Loop filter chrominance PLL (only active for PAL/NTSC standards) • PAL/SECAM sequence detection, H/2-switch generation. The increment generation circuit produces the Discrete Time Oscillator (DTO) increment for both subcarrier generation blocks. It contains a division by the increment of the line-locked clock generator to create a stable phase-locked sine signal under all conditions (e.g. for non-standard signals). The PAL delay line block eliminates crosstalk between the chrominance channels in accordance with the PAL standard requirements. For NTSC colour standards the delay line can be used as an additional vertical filter. If desired, it can be switched off by DCVF = 1. It is always disabled during VBI or raw data lines programmable by the LCRn registers (subaddresses 41H to 47H), see Section 8.2. The embedded line delay is also used for SECAM recombination (cross-over switches). 2000 Mar 15 19
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PAL/NTSC/SECAM video decoder with adaptive PAL/NTSC comb ...

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