A wideband flexible digital receiver using polyphase harmonic mixer

A wideband flexible digital receiver architecture suitable for software-defined and cognitive radios is presented. The receiver employs a polyphase harmonic mixer and exploits the harmonics caused by hard-switching commutating mixers to minimize the harmonic distortion in the signal path, reduce the tuning range of the frequency synthesizer, and sense a wider frequency spectrum. A robust digital equalizer in the presence of mixer gain/phase mismatch uncertainty is provided. The number of polyphase mixers needed for different operating interference environments is determined via simulation.