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提出了一种用于级联结构(multi-stage noise shaping,MASH)Σ-ΔADC的自适应算法,并给出了电路实现方式.该算法采用Σ-ΔADC的输出估计输入信号幅度,在不改变噪声传输函数(noise transfer function,NTF)的前提下,通过改变调制器的缩放系数,得到自适应的信号传输函数(signal transfer function,STF),从而使输出信噪比(signal to noise ratio,SNR)在自适应范围内与输入信号幅度保持独立,并给出了具体的实现方法.另外,通过改变调制器最优系数适用范围的方法,将Σ-ΔADC的量化范围提高至满幅.
An adaptive algorithm for Σ-ΔADC in multi-stage noise shaping (MASH) is proposed and the circuit implementation is given. The proposed method uses the output of Σ-Δ ADC to estimate the amplitude of the input signal without changing Under the premise of noise transfer function (NTF), an adaptive signal transfer function (STF) is obtained by changing the modulation factor of the modulator so that the signal to noise ratio (SNR) ) Is independent of the amplitude of the input signal in the adaptive range and gives a specific implementation method.In addition, by changing the scope of the optimal coefficient of the modulator, the quantization range of Σ-Δ ADC is increased to full scale.