Noise shaping in ΣΔA/D converter in high resolution seismograms
CAO Guang\|hua, YUAN Zi\|long ( Dept of Petroleum Prospecting, Daqing Petroleum Institute, Anda, Heilongjiang, China, 151400 )
Through the analysis of noise shaping in Δ modulator, the basic theory of noise shaping can be obtained and thus can provide theoretical support for the implementation of ΔA/D converter in high resolution seismograms. With specificΔ modulation circuit, this paper has analyzed the theory of noise shaping technique and its effects on the resolution of A/D converters with basic and high order loop filter. It has shown that through Δ modulator of proper order, the quantization noise generated in signal's A/D conversion process can be shifted out of the valid signal frequency band, and then can be filtered out by digital filter, thus a 24-digit high resolution A/D conversion can be realized effectively in seismograms.