Adaptive delta modulator and demodulator

摘要

PURPOSE: To reduce data transfer error and to shorten time required for making an analog demodulation signal approximate to an analog input signal being an original signal. ;CONSTITUTION: A delta value increase/decrease judgement unit 3b constituting a demodulator 11 is provided with plural kinds of judgement references. A communication signal level judgement unit 8 judges the signal state of the analog input signal and selects the appropriate judgement reference by the judged result. A storage device 5b which sets the output of an up/down counter 4 as an address stores plural delta values decided by plural delta value increase/ decrease rates as against one output of the up/down counter 4. The delta value decided by the appropriate delta value increase/decrease rate is selected in accordance with the judged result of the communication signal level judgement unit 8. Thus, the data transfer error from a modulator 1 to the demodulator 11 can be reduced, and time required for demodulating a digital modulation signal into the original signal can be shortened.;COPYRIGHT: (C)1995,JPO