JPS57140026A - Digital-to-analog converting circuit - Google Patents

Abstract

PURPOSE:To achieve high-speed D/A conversion with low cost, by adding input data to a signal delaying the input data after code conversion to input the result to an m sets of registers, and adding the content through the D/A conversion in the period m times the data period. CONSTITUTION:An input digital signal is inputted to a digital adder 102, and the output is inputted to a cascade connection circuit consisting of delay elements 103-106 via a code converter 103. An output of each delay element is inputted to the adder 102, the output of the adder 102 is inputted to the converter 103 and connected to a distribution switch 107. The switch 107 connects the output of the adder 102 to registers 108-111 sequentially and circulatingly each period of the input data. A digital value stored in each register is converted into an analog amount at D/A converters 112-115, the output is added at an adder 116 and outputted as an analog value from a terminal 117. Since the input rewriting at each register is made at a period four times the input data period, the converters 112-115 can perform high-speed D/A conversion even for low-cost and low-speed registers.