DIFFERENCE PULSE CODING SYSTEM

PURPOSE: To keep a signal error recovered at a decoder side within a prescribed period even if an error takes place in difference information on a transmission line by sending part of forecast signal in addition to the difference information from the coder side to the decoder side. CONSTITUTION:A difference signal 22 quantized by a quantization circuit 1 is coded by a coding circuit 3 and a code 24 being the difference information is written in a difference information memory 7 by a write circuit 4. The difference signal 22 is added to a forecast signal 21 at the same time to form a recovered signal 23. A decoding circuit is operated entirely opposite to the operation of the coding circuit 3 and outputs a difference signal. The difference signal is added to the forecast signal and the result is outputted at an output terminal as a recovered signal. If an error takes place in the difference information, the error of the recovered signal is kept within the time till the next forecast signal sent from the coder is used and all the succeeding signals are not in error as a conventional system.