| 摘要 |
A technique for generating a Semi-Compatible High Definition Television (SC-HDTV) signal which can be sent over two present-day Cable Television (CATV) channels. In accordance with the present invention, a HDTV signal is formed comprising a line scan rate which is a multiple of the line scan rate of a current conventional TV signal. The SC-HDTV signal is formed therefrom by transmitting a first HDTV line as is (output of 22, Fig. 5) and a second HDTV line as a field differential signal (output of 25) transmitted via QAM on the IF or RF carrier of the first line signal at a line scan rate of a current conventional TV signal (40-41, 43-47, Fig. 7). Arrangements are also disclosed for converting the SC-HDTV signal back into either a HDTV (Fig. 9) or conventional TV signal (Fig. 10). |
