公开(公告)号：US4479142A

公开(公告)日：1984-10-23

申请号：US379382

申请日：1982-05-17

申请人： Bob D. Buschman ,  Glenn D. Muth ,  Ronald T. O'Connell

发明人： Bob D. Buschman ,  Glenn D. Muth ,  Ronald T. O'Connell

IPC分类号： H04N7/56 ,  H04N11/04 ,  H04N21/236 ,  H04N21/2368 ,  H04N21/2383 ,  H04N21/242 ,  H04N9/32 ,  H04N7/08 ,  H04N9/42

CPC分类号： H04J3/1623 ,  H04N11/046 ,  H04N21/23614 ,  H04N21/2368 ,  H04N21/2383 ,  H04N21/242 ,  H04N7/56

摘要： 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. This is useful at the receiver for ensuring that f.sub.sc at the receiver will track f.sub.sc at the transmitter. In accordance with standard T3 operation, the frame comprises 56 85-bit words, 28 odd and 28 even. The first bit of each 85-bit word is a control bit. Substantially all of the odd words include a 4-bit digitized audio nibble. Exceptions are two unused 4-bit nibbles, a single 4-bit stuff opportunity nibble and a single 4-bit video sample. Each of the even words includes 21 4-bit video samples which can be either video samples or sync indicating code words.

摘要翻译： 以标准T3数据格式传输数字编码（DPCM）NTSC视频，并通过发送接口模块进行速率传输。 该模块经受包括DPCM编码的NTSC视频，水平同步和3fsc的视频采样时钟的输入，其中fsc是彩色副载波频率。 采样时钟用于将DPCM编码视频和水平同步写入缓冲区。 缓冲器通过读时钟读出，读时钟是44736 MHz T3速率的一个倍数。 为了辅助接收机解码，视频数据被补充有指示每个水平扫描线的开始的水平同步指示码字。 在检测到从缓冲存储器读出的水平同步字时，读取时钟被禁止插入水平同步指示码字。 T3帧还补充了两个数字化的音频通道，内容指示器和一个机会插槽以及奇偶校验，帧和多帧指示器以及一个报警通道。 T3帧还携带指示T3时钟和fsc之间的关系的数据。 这在接收机上是有用的，以确保接收机的fsc将跟踪发射机上的fsc。 根据标准T3操作，该帧包括56个85位字，28个奇偶和28个字。 每个85位字的第一位是一个控制位。 基本上所有的奇数字包括4位数字化音频半字节。 例外是两个未使用的4位半字节，一个4位的填充机会半字节和一个4位的视频样本。 每个偶数字包括21个4位视频样本，可以是视频采样或同步指示码字。