DIGITAL-ANALOG CONVERTER

摘要

PURPOSE:To prevent generation of spectrum reflected noises by providing a noncyclic type filter to an input section in applying bit compression to a digital input signal to attain D/A conversion via a PWM modulator and an analog integration device. CONSTITUTION:A digital input signal Xi is applied with bit compression into a signal Yi comprising a high-order bit only by using an accumulated adder comprising a register 2 activated by a clock frequency n fs being n times the clock frequency of the input signal and an adder 1. The signal is inputted to the PWM modulator consisting of a counter 3 and a flip-flop 4 and its modulation output is subject to analog integration via an analog integration device 5. Since two noise spectrums having clock frequencies fs and n.fs appear in the signal, the noncyclic filter comprising an adder 11 and a regiter 12 is provided to the input section to prevent generation of noises.