JPS55166322A - Digital filter - Google Patents

Abstract

PURPOSE:To obtain a miniature and simple-structure digital filter of low power consumption, by supplying the outputs of the subtractor and the contractor to the memory circuit via the switching gate and then delivering the delayed reflected signal from the memory circuit. CONSTITUTION:Multiplier 41 calculates the traveling wave and then uses the multiplication output and the self-addition output for the added input of adder 51. The output of adder 51 is delivered after D/A conversion 61 and at the same time supplied to multiplier 42 for multiplication by the reflecting coefficient signal. Then subtraction 52 is carried out between the output of above multiplication and the output of memory circuit 24, and the subtraction result is led to switching gate 33. Gate 33 applies the outputs of subtractor 52 and adder 51 to circuit 24, and then supplies the reflected delay signal to gate circuit 31 and subtractor 52 from circuit 24. As a result, a filter for waveform composition can be formed in a simple constitution, and then a miniature digital filter can be obtained with the low power consumption.