To provide the digital transmitter in which transmission is efficiently conducted by attaining interpolation processing in the unit of packets even when a data length in a transmission packet is variable.

A compressed process information addition means 105 adds information of a compression process by a compression means 101 in a compression signal included in a block to a block signal with a prescribed length of a signal obtained by a block processing means 107. The block signal with information of compression process added thereto is given to an error check/ correction coding means 4, in which the signal is subject to error check/ correction coding and the resulting signal is sent by a transmission means 6. The transmitted signal is given to an error check/correction processing means 8, in which error check/correction processing is conducted, and an expansion means 109 and an interpolation means 112 conduct expansion and interpolation processing using the compression process information depending on a state of error display obtained as a result.