DPCM CODING DEVICE

PURPOSE:To attain proper coding without error due to inversion by regulating a conversion code outputted from a conversion code output means in response to the code of a difference detected by the 1st detection means and the result discriminated by an overflow discrimination means. CONSTITUTION:The coder consists of an input section 12, adders 14, 24, 30, 32, 34, 40, quantization tables 16, 18, a PF latch 20, an OF latch 22, inverters 26, 28, a decoding table 38, a latch 42, a complement number generating section 44 and an output section 36. Then a conversion code outputted from a conversion code output means is regulated depending on the sign of a difference detected by the 1st detection means detecting whether or not the inputted data and the data inputted before the first data is 0 or over and on the result of discrimination by an overflow discrimination means discriminating whether or not the decoded value of the inputted data exceeds a prescribed data quantity. Thus, the proper conversion code and the output value without any error due to inversion are obtained.