【摘要】 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.更多还原

【Abstract】 An exponential adaptive algorithm forΣ-ΔADC based on multi-stage noise shaping(MASH)modulator along with the implementation in circuit level is presented.This algorithm uses the output of theΣ-ΔADC to estimate the input signal amplitude.Without changing the noise transfer function(NTF),signal transfer function(STF)which is adaptive can be gain through altering the scaling factors of the modulator,making signal to noise ratio(SNR)independent to input signal amplitude in the adaptive range.The implementation of the algorithm is also proposed.By changing the sphere of application of the modulator optimal value,the input range is extended to the full scale.更多还原