Conexant Systems, Inc.

Peter M Murdock

John E Welch

Havard Lee Scott

Lior Levin

Harvard L Scott

Chris J Delgrande

An automatic Video Detector ('AVD') for detecting the transmission format of a received video signal is disclosed. The AVD may include a video detector array module and a state machine. The video detector array module may include a video line detector and a sub-carrier frequency detection module in signal communication with the video line detector.

Automatic video detector

Provided are decoding methods and decoders for separating luminance and chrominance components of a video signal. In one aspect, a reference subcarrier of a first line of the video signal is used for subsequent lines by applying an appropriate rotation to the reference subcarrier of the first line for each subsequent line. In another aspect, comb filtering is adaptively controlled based on determining whether 90 or 180 degrees relationship is maintained from line to line. In a further aspect, both complimentary and non-complimentary comb filtering are implemented. In yet another aspect, SECAM bell filtering is achieved by rotating the video signal to obtain a baseband signal, low-pass filtering and modulating the baseband signal, and subtracting the modulated low-pass filtered baseband signal from the video signal to notch the chroma component from the luma component.

Decoding video signals to separate luma and chroma components

Luminance and chrominance separation system

Provided are decoding methods and decoders for calculating comb filter error and performing comb filter calculation used for decoding video signals. In one aspect, a method of calculating comb filter error used for decoding a video signal comprises storing a plurality of consecutive video lines of the video signal, the plurality of consecutive video lines including a first video line, a second video line appearing immediately before the first video line, and a third video line appearing immediately before the second video line; receiving a current video line of the video signal, wherein the current video line appears immediately after the first video line; obtaining a first difference between the current video line and the second video line; obtaining a second difference between the first video line and the third video line; and filtering the video signal for separating components in the video signal, based on the differences.

Comb filter design for separating luminance and chrominance in video signals

Methods and systems are described for determining a slice level used for detecting an edge of a horizontal sync pulse of a horizontal line of a video signal, where the horizontal line has a plurality of samples. An exemplary method comprises low-pass filtering the video signal to generate a plurality of filtered samples; determining a first level, wherein a predetermined number of the plurality of filtered samples have levels above the first level; determining a second level, wherein the second level is a minimum level of levels for the plurality of filtered samples; and determining the slice level by adding the first level and the second level to generate a summed level, and dividing the summed level by two to determine the slice level.

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San Diego, CA, United States of America

Peter M Murdock