A novel wideband low-distortion cascaded sigma-delta ADC

This work presents a novel noise-shaping cascaded sigma-delta modulator that incorporates two stages. The first stage is realized by low-order single bit architecture, while the second stage is realized by a high-order feed-forward multi-bit architecture. Moreover, the error cancellation schemes can be added in the digital circuit part to cancel the coarse quantization errors and thus effectively reduce the non-ideal effects such as DAC mismatch. However, it can reduce the nonlinear effects between two stages by using low-distortion topology in the first stage. By these arrangements, this architecture can reduce the over sampling ratio (OSR) effectively and the in-band noise can be suppressed significantly to achieve high resolution. The simulation shows this sigma-delta modulator reveals a very good efficiency in the wide bandwidth application