The error analysis of sigma delta modulator

There are some special characteristics such as high precision, low cost and easy finish the system design for sigma delta A/D converter. If omitted the complicated digital decimator, the precision and rate of A/D conversion will depend on the way of system design. In this paper, the error of first order sigma delta modulator was analyzed with dc input. Based on the periodic character of the output 1-bit data stream when input is a rational, the conclusion were given that the error will decreasing along with the increase of account pulse and the least error will occur when average calculation in a period. This is a theory warranty for engineers to design a fast, high precision A/D converter application with sigma delta modulator.