Digital demodulation method for non-synchronous composite video signal and S video signal

Abstract

The invention relates to a digital demodulation method and a demodulator for a non-synchronous composite video signal and an S video signal. The method comprises the following steps: a fixed sampling clock is set to collect data for the entire demodulation process; the composite video signal or the S video signal is converted into an initial digital signal; a field-synchronizing signal and a line synchronizing signal in the initial digital signal are restored, and the field frequency and the line frequency in the initial digital signal are calculated and locked; the color intensity in the initial digital signal is demodulated; a line synchronizing phase is secondarily sampled by the interpolation method; the phase is adjusted; the intense color is separated; and the brightness, the contrast degree and the saturation degree are adjusted. By utilizing the invention, the dependence on an analog phase-locked loop in a video demodulator can be eliminated. The phase-locked loop is the important core in the digital video demodulator and is the only one who cannot be separated from the analog. Therefore, in an integrated circuit of the digital video demodulator, not only the reducing of the area and complexity of the integrated circuit is realized, but also the effect brought by using the phase-locked loop is also achieved.

Description

technical field [0001] The present invention relates to a digital demodulation method and a demodulator of a composite video signal (composite) and an S-video signal (S-Video), and more particularly relates to a demodulation process completed in an asynchronous system without any Digital demodulation method and demodulator of composite video signal and S-video signal of synchronous mechanism. Background technique [0002] Composite Video and S-Video are the most commonly used video signal types today, and involve the lowest equipment and cost. Although the video system has entered the high-definition era, composite video signals and S-video signals are still widely used because more cost support is required to complete the playback and reception of high-definition signals. [0003] A composite video signal is a single video signal composed of three basic elements (luminance, chrominance, and sync). The S video signal is composed of two elements, one is a signal bundled wit...

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to provide a digital demodulation method and demodulator of a non-synchronous composite video signal and S-video signal, to overcome the current demodulation method depends on the phase-locked loop, resulting in large demodulation difficulty and demodulation cost high technical issues

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