STW8019 datasheet(11/55 Pages) STMICROELECTRONICS

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STw8009/STw8019

Functional description

11/55

4.5

Sub-carrier generation

A Direct Digital Frequency Synthesizer (DDFS) generates the required color sub-carrier

frequency using a 24-bit phase accumulator. Sub-carrier frequency is programmable with a

1.6 Hz step.

4.6

Luminance encoding

The luminance that is added to the chrominance to create the composite CVBS signal can

be trap-filtered at 3.58 MHz (NTSC) or 4.43 MHz (PAL). This supports application oriented

towards low-end TV sets which are subject to cross-color.

A 7.5 IRE pedestal can be programmed if needed with all standards. This allows in

particular to encode Argentinian and non-Argentinian PAL-N, or Japanese NTSC.

A programmable delay can be inserted on the luminance path to offset any chroma/luma

delay introduced by off-chip filtering.

STw8009/STw8019 output signals are IF modulated in NTSC M standard so that a sound

notch filter is required. The notch filter which is on the Luma path is defined by a set of

coefficients and is implemented in the STw8009/STw8019 as default values. The set is also

programmable.

Figure 5.

Luma filtering

Amplitude (dB)

Frequency (MHz)

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