Glenn Douglas Muth

US Patent:

44791429, Oct 23, 1984

Filed:

May 17, 1982

Appl. No.:

6/379382

Inventors:

Bob D. Buschman - Gaithersburg MD
Glenn D. Muth - Frederick MD
Ronald T. O'Connell - Germantown MD

Assignee:

M/A-COM DCC, Inc. - Germantown MD

International Classification:

H04N 932
H04N 942
H04N 708

US Classification:

358 13

Abstract:

Digitally encoded (DPCM) NTSC video is transmitted in a standard T3 data format and rate via a transmit interface module. The module is subjected to inputs comprising DPCM encoded NTSC video, horizontal sync and a video sampling clock at 3f. sub. sc, where f. sub. sc is the color subcarrier frequency. The sampling clock is used to write the DPCM encoded video and horizontal sync into a buffer. The buffer is read out via a read clock which is a submultiple of the 44736 MHz T3 rate. To assist in receiver decoding, the video data is supplemented with horizontal sync indicating code words, which designate the start of each horizontal scan line. On detection of a horizontal sync word read out of the buffer memory, the read clock is inhibited for the insertion of the horizontal sync indicating code words. The T3 frame is also supplemented with two digitized audio channels, stuff indicators and a stuff opportunity slot as well as parity, frame and multiframe indicators and an alarm channel. The T3 frame also carries data indicating a relationship between the T3 clock and f. sub. sc.