Integrated multistandard comb filter

INTEGRATED CIRCUITS DATA SHEET TDA9181 Integrated multistandard comb filter Objective specification File under Integrated Circuits, IC02 2000 Nov 22 Philips Semiconductors Objective specification Integrated multistandard comb filter FEATURES • One-chip multistandard adaptive comb filter • Cross luminance reduction • Cross colour reduction • No chroma trap, therefore sharper vertical luminance transients • Analog discrete-time signal processing, therefore no quantization noise • Anti-aliasing and reconstruction filters are included • Input switch selects between two Y/CVBS inputs • Output switch selects between combed CVBS and an external Y/C source • fSC as well as 2 × fSC colour subcarrier signal may be applied • Alignment free • Few external components • Low power. GENERAL DESCRIPTION TDA9181 The TDA9181 is a an adaptive PAL/NTSC comb filter with two internal delay lines, filters, clock control and input clamps. Video standards PAL B, G, H, D, I, M and N and NTSC M are supported. Two CVBS input signals can be selected by means of an input switch. The selected CVBS input signal is filtered to obtain a combed luminance output signal and a combed chrominance output signal. Switched capacitor circuit techniques are used, requiring an internal clock, locked on to the colour subcarrier frequency. The colour subcarrier frequency as well as twice the colour subcarrier frequency may be applied to the IC. In addition to the comb filter the circuit contains an output switch so that a selection can be made between the combed CVBS signal and an external Y/C signal. The IC is available in a DIP16 and SO16 package. The supply voltage is 5 V. QUICK REFERENCE DATA SYMBOL VCCA ICCA VDDD IDDD Vi(Y/CVBS)(p-p) Vi(CIN)(p-p) Vi(FSC)(p-p) Vo(Y/CVBS)(p-p) Vo(CIN)(p-p) analog supply voltage analog supply current digital supply voltage digital supply current luminance or CVBS input signal voltage (peak-to-peak value) chrominance input signal voltage (peak-to-peak value) colour subcarrier input signal voltage (peak-to-peak value) luminance or CVBS output signal voltage (peak-to-peak value) chrominance output signal voltage (peak-to-peak value) PARAMETER MIN. 4.5 − 4.5 − 0.7 − 100 0.6 − TYP. 5.0 25 5.0 10 1.0 0.7 200 1.0 0.7 MAX. 5.5 − 5.5 − 1.4 1.0 400 1.54 1.1 UNIT V mA V mA V V mV V V ORDERING INFORMATION TYPE NUMBER TDA9181P TDA9181T PACKAGE NAME DIP16 SO16 DESCRIPTION plastic dual in-line package; 16 leads (300 mil); long body plastic small outline package; 16 leads; body width 7.5 mm VERSION SOT38-4 SOT162-1 2000 Nov 22 2 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 Nov 22 handbook, full pagewidth BLOCK DIAGRAM Philips Semiconductors Integrated multistandard comb filter VCCA 6 VDDD 5 14 INPSEL Y/CVBS1 2 12 Y/CVBSOUT CLAMP LPF 2H/4H DELAY ADAPTIVE COMB FILTER LPF Y/CVBS2 3 CLAMP LPF TDA9181 1 7 FILTER TUNING (LPFs) 9 4 × fsc CLOCK GENERATOR 16 COUT 3 CIN SC SANDCASTLE DETECTOR 8 11 10 13 4 15 FSC FSCSEL SYS1 SYS2 AGND DGND OUTSEL MGT518 Objective specification TDA9181 Fig.1 Block diagram. Philips Semiconductors Objective specification Integrated multistandard comb filter PINNING SYMBOL CIN INPSEL Y/CVBS2 DGND VDDD VCCA SC FSCSEL FSC SYS2 SYS1 Y/CVBS1 AGND Y/CVBSOUT OUTSEL COUT PIN 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 TDA9181 DESCRIPTION chrominance signal input input switch select input luminance or CVBS signal 2 input digital ground digital supply voltage analog supply voltage sandcastle signal input colour subcarrier select input colour subcarrier input signal standard select 2 input standard select 1 input luminance or CVBS signal 1 input analog ground (signal reference) luminance or CVBS signal output output switch select input chrominance signal output handbook, halfpage CIN 1 handbook, halfpage 16 COUT 15 OUTSEL 14 Y/CVBSOUT 13 AGND CIN 1 16 COUT 15 OUTSEL 14 Y/CVBSOUT 13 AGND INPSEL 2 Y/CVBS2 3 DGND 4 INPSEL 2 Y/CVBS2 3 DGND 4 TDA9181P VDDD 5 VCCA 6 SC 7 FSCSEL 8 MGT519 TDA9181T 12 Y/CVBS1 11 SYS1 10 SYS2 9 FSC VDDD 5 VCCA 6 SC 7 FSCSEL 8 MGT520 12 Y/CVBS1 11 SYS1 10 SYS2 9 FSC Fig.2 Pin configuration (DIP16). Fig.3 Pin configuration (SO16). 2000 Nov 22 4 Philips Semiconductors Objective specification Integrated multistandard comb filter FUNCTIONAL DESCRIPTION Input configuration The Y/CVBS1 and Y/CVBS2 input signals are clamped by means of an internally generated clamp pulse which is derived from the sandcastle input signal (pin SC). If no sandcastle signal is available, a clamp pulse signal may be applied to pin SC. External clamp capacitors are needed. The buffered and clamped Y/CVBS1 and Y/CVBS2 signals are then applied to the input switch. The input switch select signal (INPSEL) determines whether Y/CVBS1 or Y/CVBS2 is passed through to the anti-alias low-pass filter. This 3rd-order low-pass filter is optimized for best performance with respect to step response and clock suppression. The filtered signal is sampled at a clock frequency of four times the colour subcarrier frequency (fSC). A colour subcarrier frequency signal is applied to pin FSC. The colour subcarrier select input signal (FSCSEL) indicates whether the colour subcarrier frequency (fSC) or twice the colour subcarrier frequency (2 × fSC) is being applied at the FSC input. An external coupling capacitor is needed for the colour subcarrier input signal. Comb filter The sampled CVBS signal is applied to two delay lines. Depending on the applied standard, one delay line delays the signal over 1 or 2H for NTSC and PAL respectively (1H = one line-time). The standard select inputs SYS1 and SYS2 indicate which standard, PAL B, G, H, D, I, M, N or NTSC M, is being applied. The direct and delayed signals are applied to an adaptive comb filter. The adaptive comb filter performs band-pass filtering around the colour subcarrier frequency and compares the contents of adjacent lines. In this way the combing of signals with different information is prevented and artifacts such as hanging dots are avoided. Both the combed chrominance and the combed luminance signals are passed through a reconstruction low-pass filter to obtain continuous-time signals. These low-pass filters are 3rd-order, optimized for best performance with respect to step response and clock suppression. The reconstructed signals are applied to the output switches. Output configuration TDA9181 The luminance output switch selects between the reconstructed combed luminance signal and one of the buffered and clamped input signals, Y/CVBS1 or Y/CVBS2. The chrominance output switch selects between the reconstructed combed chrominance signal and the chrominance input signal (CIN). An external coupling capacitor is needed for CIN. The selected signals are applied to the outputs Y/CVBSOUT and COUT respectively via a buffer stage. The output switch signal (OUTSEL) determines whether the output switches select the internal combed signals or the external Y/C signals. Clock generation and filter tuning The clock generator is driven by a Phase-Locked Loop (PLL) circuit which generates a reference frequency of four times the colour subcarrier frequency. This PLL circuit is phase-locked to the colour subcarrier input signal (FSC). Several internal clock signals are derived from the 4 × fSC reference. The filter tuning ensures the automatic alignment of the anti-alias and the reconstruction low-pass filters. A 4 × fSC clock signal is used as a reference for the alignment. The tuning takes place each line during the line blanking and is initiated by means of an internally generated signal which is derived from the sandcastle input signal. If the output switches select external Y/C signals the oscillator of the PLL circuit is stopped regardless of the FSC input and no internal clock signals are generated. The filter tuning is also stopped. 2000 Nov 22 5 Philips Semiconductors Objective specification Integrated multistandard comb filter Mode definitions Table 1 General mode definitions; note 1 MODE COMB YC Table 5 FSC mode definitions; note 1 TDA9181 PIN FSCSEL LOW HIGH Note FSC INPUT SIGNAL FREQUENCY fSC 2 × fSC PIN OUTSEL LOW HIGH Note 1. If the OUTSEL pin is left open-circuit, the pin is pulled LOW by means of an internal pull-down resistor to analog ground (AGND). Thus the COMB mode can also be selected by not connecting the OUTSEL pin. Table 2 Y/CVBSOUT output signal definitions MODE COMB YC Table 3 Y/CVBSOUT OUTPUT SIGNAL comb filtered luminance signal Y/CVBS1 or Y/CVBS2 signal COUT output signal definitions MODE COMB YC Table 4 COUT OUTPUT SIGNAL comb filtered chrominance signal CIN signal Input switch mode definitions; note 1 INPUT SWITCH MODE Y/CVBS1 input selected Y/CVBS2 input selected 1. If the FSCSEL pin is left open-circuit, the pin is pulled LOW by means of an internal pull-down resistor to analog ground (AGND). Thus the fSC mode can also be selected by not connecting the FSCSEL pin. Table 6 Video standard mode definitions; note 1 PIN SYS2 LOW HIGH LOW HIGH VIDEO STANDARD PAL M PAL B, G, H, D or I NTSC M PAL N PIN SYS1 LOW LOW HIGH HIGH Note PIN INPSEL LOW HIGH Note 1. If the SYS1 and SYS2 pins are left open-circuit, the SYS1 pin is pulled HIGH by means of an internal pull-up resistor to analog supply (VCCA) and the SYS2 pin is pulled LOW by means of an internal pull-down resistor to analog ground (AGND). Thus the NTSC M video standard can also be selected by not connecting pins SYS1 and SYS2. 1. If the INPSEL pin is left open-circuit, the pin is pulled LOW by m