A facsimile system with compression and channel coding

A digital facsimile equipment set has been developed for operation in a European communications network. The compression technique, termed predictive quantizing, is essentially a quantizing technique making use of the redundancy in contiguous lines of facsimile. The system utilizes the 3/4 rate feedback convolutional forward error correction (FEC) and digital equipment, and restricts the facsimile encoder to the run length encoding mode. The configuration provides a factor of three speedup and provides a highly readable output under poor line conditions. Provisions for the use of varying degrees of line correlation encoding and for bypass of FECs are included to allow for faster operation in the future.