A two-path bandpass /spl Sigma//spl Delta/ modulator with extended noise shaping

The proliferation of communications applications stimulates interest in digitizing bandpass signals with bandwidths of several MHz at intermediate frequencies above 10 MHz. This multistage oversampling modulator combines lowpass and bandpass stages to achieve an extended dynamic range at low oversampling ratios. An experimental prototype of the architecture integrated in 0.25 /spl mu/m CMOS achieves 75 dB dynamic range for 2 MHz signal bandwidth at 16 MHz IF.