Noise shaping sigma delta modulation techniques and models simulation

With high resolution ADC has been widespread used in communication and multimedia, oversampling Sigma-Delta ADC becomes the main path of implementing high resolution ADC. Oversampling Sigma-Delta ADC is composed of two basic blocks: a noise shaping sigma delta modulator and a digital signal processing block for filtering and decimation. This paper mainly discuss noise shaping sigma delta modulation techniques, theory and structure. Followed by a discussion of the advantage of high-order structure, then discussed its stability. This paper use the method of adding gain (<1) before the integrator to solve stable problem. In this paper, precise models of fourth-order structure are presented followed by SIMULINK, implemented a modulator with an oversampling frequency of 2.5 MHz