Conexant Systems, Inc.

Rockwell Semiconductor Systems, Inc.

John E Welch

Peter M Murdock

Benjamin E Felts, Iii

Torry J Steed

Michael A Eskin

Matthew J DiMeo

Harvard L Scott

Lauren E Linstad

Chris J Delgrande

A comb filter system that utilizes host memory is disclosed. The comb filter system that utilizes host memory may include a comb filter. The comb filter system that utilizes host memory may include an allocated host memory. The comb filter system that utilizes host memory may include an interface in signal communication with the comb filter and allocated host memory.

Comb filter that utilizes host memory

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

An adaptive signal separation system and method for quadrature amplitude modulated signals that is particularly well-suited for YC separation of a composite television signal. An adaptive approach for separating overlapping signals wherein the adaptive approach selects between notch or equivalent filtering and a comb filtering system, wherein the chrominance is first demodulated to the IQ domain prior to comb filtering. The demodulated comb filtered IQ data streams are then re-modulated to reconstruct the luminance portion of the signal.

Comb filtered signal separation

An adaptive method and system for processing luma and chroma signals from lines of a video signal. The invention includes an adaptive comb filtering algorithm that determines whether to average lines of video data based on the signal content. If two lines are dissimilar, a simple notch/bandpass system is used. The invention provides improved adaptive comb filtering performance at vertical transitions between high-luminance-detail areas and between other areas such as solid colors or flat gray or white fields by dynamically determining whether to average the chrominance information of the current video line with the chrominance information of the previous line, next line, both of such lines, or neither of such lines. In one aspect, the invention includes determining whether to average a current chroma value of a current video line with corresponding chroma values of the previous line, next line, or both of such lines, or neither of such lines; computing an output value for the current chroma value in response to such determination; determining a luminance correction from the current chroma value and the computed output value; and applying the luminance correction to a luma value corresponding to the current chroma value to correct any changes to the luma value.

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Encinitas, CA, United States of America

John E Welch