A novel structure for the design of 2-1-1 cascaded continuous time delta sigma modulators

A new structure for the design of the 2-1-1 cascaded continuous time delta sigma modulators is proposed in this paper. It uses the output of the sampling switch to generate the error signal as the input of the next stage of the cascaded modulator whereas in the previous published structures, the input of the sampler is used to generate the error signal, involving a lot of additional feed-forward paths. The proposed method doesn´t require to employ additional feed-forward paths and the structure of the cascaded CT DSM will be as its DT counterpart. The MATLAB and HSPICE simulation results confirm the validity of the proposed structure