Rca Inc.

Charles R Thompson

Glenn A Reitmeier

Robert E Flory

A wide-aspect-ratio HDTV signal having 1600 luminance pixels/32 .mu.S line and 980 lines/frame is data reduced by deleting odd pixels of each line of TV field #1 and even pixels of each line of TV field #2 to produce 800 pixels per line, and is further data compressed by a form of differential-pulse-code modulation. The DPCM organizes the pixels into groups of five, and for each group transmits or records one reference pixel at full N-bits. The pixels to the right and left of the reference pixel are compared therewith to produce difference signals of M bits, where M&lt;N. The remaining two pixels of each group are compared with reference pixels from the lines above and below to form M-bit difference signals. The difference signals are transmitted. The DPCM coding reduces the 800 pixels/line to the equivalent of 480 pixels/line. The color portion of the wide-aspect-ratio HDTV is similarly coded to produce the equivalent of 240 pixel/line. The 480 luminance samples and 240 color samples are added to form 720 samples/line, or 1440 samples/64 .mu.sec which can be accommodated by a CCIR-standard-601 signal processing system.

Differential PCM video transmission system employing horizontally offset

A synchronization system for serial digital television signals compares successive sync signals to form an error signal and also delays the digital signals. The information signal delay is changed during loss of signal by an amount in accordance with the error signal to resync the signal. Thus valid information occuring before loss of synchronization is utilized. The delay means can comprise a pair of RAMs.

Synchronization system that uses all valid signals

When PAL chroma signals U and V are respectively recorded in channels with bandwidths intended for NTSC chroma signals I and Q, distortion will result to one of the U or V signals due to the narrow bandwidth Q channel. To equalize this distortion between the U and V signals, they line to line alternate between the two channels. To avoid a line crawl, signals above the Q channel cut-off frequency are averaged.

Chrominance channel bandwidth modification system

A recording system converts standard binary signals into new binary signals that have mostly zeroes occurring in words that are physically unrealizable. Thus when NRZ-I recording is used, long strings of zeroes (which have no transitions in them for easy detection) do not actually occur. Ones do have transitions in them for easy detection, and thus a long string of ones causes no detection problem. The physically unrealizable combinations occur due to the partial correlations of signals, such as Y, B-Y, and R-Y color signals.

Growing community of inventors

Moorestown, NJ, United States of America

Charles R Thompson