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The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.

The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.

Patent No.:

US 4782387 B1

PDFFull Text
Date of Patent:
Nov. 01, 1988

Filed:

Dec. 09, 1986

Two-channel coding of digital signals

Applicant:
Inventors:

Mohamed S Sabri, Beaconsfield, CA;

Albert Golembiowski, Nuns' Island, CA;

Birendra Prasada, Westmount, CA;

Assignee:

Northern Telecom Limited, Montreal, CA;

Attorney:

Adams; Thomas

Primary Examiner:

James J Groody

Assistant Examiner:

John K Peng

Int. Cl.
CPC ...
H04N / ;
U.S. Cl.
CPC ...
358133 ; 358135 ; 358138 ; 358 12 ; 375 28 ; 341 88 ;
Abstract

A video codec is used to reduce the bandwidth of a video signal for storage and/or transmission. To transmit an uncoded quality color NTSC television signal is digitized form requires channel bandwidth typically 90-120 Mb/s for the signal in the composite format and 216 Mb/s for the signal in the component format. The proposed video codec achieves a reduction of the required transmission bandwidth by a factor of 2-3 by splitting the imput signal into two channels, a main and a complementary channel, and by applying different coding techniques in each. In the main channel the input signal is subsampled and DPCM encoded using a fixed-rate companded quantization, whereas VWL and block coding is used to encode the complementary channel carrying the interpolation error signal. This arrangement seeks to ensure high picture quality while being easily adaptable to different transmission rates and signal formats. In bandwidth-on-demand applications the main channel cna be used alone to provide a lesser quality signal, for example CATV quality at 35 Md/s, with an attendant reduction in system complexity.

Find Patent Forward Citations

Sabri, Mohamed. (1988). Two-channel coding of digital signals (U.S. Patent No. 4782387). U.S. Patent and Trademark Office. https://idiyas.com/patent/badge/4782387

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