Abstract: This paper introduces a kind of design method about the digital decimation filter design for Sigma-delta ADC with high performance, analyze its features of frequency and high pass filter, and give the results of simulation. The decimation filter can be applied to 1 bit, 128 times the rate of oversampling for S-? modulator, and can form a complete S-? A/D converter with S-? modulator. The area of this device is small, and the power consumption is very low with high precision. It can be easily realized with hardware in the SOC ASIC design and suitable for audio system.

Keywords: A/D Converter, Decimation Filter, FIR Filter.