TDA8501 datasheet(8/30 Pages) PHILIPS

8 / 30 page

April 1993

Philips Semiconductors

Preliminary speciﬁcation

PAL/NTSC encoder

TDA8501

CHROMINANCE BLANKING

The signal outputs from the modulators are connected to

the signal input of the chrominance blanking circuit. To

avoid signal distortion that may be caused by the control

loop, the signal outputs of the modulators are blanked

during the sync period. This prevents signal distortion

during the adding of the sync pulse at the CVBS output

circuit.

BANDPASS FILTER

A wide symmetrical bandpass filter is used so that a

maximum performance of the chrominance for Y +C

(SVHS) is guaranteed. This wide curve is possible

because of the minimal signal level of the harmonics within

the modulators see Figs (PAL mode: 5 and 6);

(NTSC mode: 7 and 8) which illustrate the nominal

response for PAL and NTSC modes.

Fig.5

Band pass filter nominal frequency

response (PAL mode).

Fig.6

Band pass filter nominal frequency/group

delay response (PAL mode).

(1) frequency response.

(2) group delay.

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