miyu - teingu device of DPCM code decoder

摘要

PURPOSE: To reduction a pulse noise at muting by providing the 1st gate and the 2nd gate to the output of a DPCM coder and the input of a DPCM decoder so as to make zero a transmission difference signal thereby reducing gradually an analog output. CONSTITUTION: The ON/OFF of muting based ON the request of a DPCM coder is controlled by the 1st control terminal 61 and the ON/OFF based ON the request of the DPCM decoder is controlled at the 2nd control terminal 81. Since a transmission data in 8-bit is muted digitally before and after a transmission line by the muting ON in both the cases and the DPCM decoder acts that other difference data are zero. That is, the data subject to nonlinear extansion by an inverse quantizer 9 is zero as well, then an input to a leaked integration device 10 is zero and since no new integration data exists and the output of the leakage integration device holds the preceding value. However, since the leaked component exists and the output of the leakage integration device is reduced gradually and reaches zero for some time.