| 摘要 |
A coding of images and originals, for example for telefax and colour television, allows transmission time to be shortened, in particular in the case of black and white digital or numeric longitudinal coding. For that purpose, the same code words for black and white are provided also for different numbers or digits. As discriminating criterion, the input sequence of black and white is used. During coding of several successive white lines, transmission time can be further shortened in that the coded number of white lines is provided before or after the code word for the white line. During gray coding, transmission time is in particular reduced by subdividing the gray scales or binary code words, if necessary with deliberate redundancy, since in this case many characters occur successively and are then transmitted in the same way as the white lines. During colour image transmission, transmission time is further reduced by code multiplexing and if necessary by QAM-based transmission, whereas in addition the PAM-coded information is D.C. biased. The sum alternating current thus varies in phases in the range of 90 DEG only. |
