PROCEDE D'INTERPOLATION GENERALISEE DE CONVERSION NUMERIQUE-ANALOGIQUE DE SIGNAUX PCM

摘要

A method for effecting digital to analog conversion of PCM signals by a generalized interpolative procedure, by sampling the PCM signals at a first sampling rate and supplying each sampled word in succession to a first input of a digital adder; dividing each word at the output of the adder into a first part representing the higher value portion of the adder output word and having a length shorter than that of the adder input word, and a second part representing the lower value part of the adder output word; conducting the second part of each adder output word through a digital, nonrecursive counter feedback filter having a degree greater than one at a clock pulse rate which is an integral multiple of the sampling rate, and supplying each resulting word at the filter output to a second input of the digital adder where it is added to the stored word at the first adder input; converting the first part of each adder output word into an analog signal in a digital/analog converter having a small number of available output values; and passing the analog signal at the output of the converter through an analog lowpass filter.