| 摘要 |
PURPOSE:To prevent generation of propagation of an error over a long period by transmititng a data relating to a high-order bit of one data at each data string in data strings where preceding and succeeding data have mutually correlation together with a data string based on the difference between adjacent data. CONSTITUTION:An 8-bit data obtained by sampling an analog signal inputted from an input terminal 5 is converted into a DPCM data by a DPCM encoder 8 and then fed to a high-order bi extraction circuit 51. After the circuit 51 adds '1' to the 5th bit from the high-order in the 8-bit data, the high-order 4-bit is separated and the result is fed to a multiplexer 52. The multiplexr 52 arranges in time division the coarse PCM data thus obtained and the DPCM data outputted from one encoder 8 at one data block. The output data of the multiplexer 52 is added with a redundancy bit by an error correction code addition circuit 9 and with a synchronizing signal by a synchronizing signal addition circuit 10, and the result is sent to a transmission line 12.
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