A complex bandpass /spl Delta//spl Sigma/ converter for digital radio

A new architecture is proposed for a single-chip digital radio receiver. This architecture has several advantages over the direct-conversion architecture that has been gaining interest for use in single-chip designs. A non-zero quadrature IF reduces the image problem and eliminates concerns about self-EMI and 1/f noise. A complex bandpass filter embedded in a delta-sigma loop allows the A/D conversion to be performed directly on the pair of quadrature outputs from the mixer.<<ETX>>