Spur and Distortion Management Techniques for an RF Receiver

摘要

A receiver ( 1800 ) includes a mixing digital-to-analog converter (DAC) ( 1807 ), a direct digital frequency synthesizer (DDFS) ( 1848 ), a first power detector ( 1826 ), and a first control circuit ( 1834 ). The mixing DAC ( 1807 ) receives a digital local oscillator (LO) signal and a radio frequency (RF) signal and provides an output signal located in a first frequency band. The DDFS ( 1848 ) includes a first clock input that is configured to receive a first clock signal that sets a sample rate for the digital LO signal. The first power detector ( 1826 ) has an input coupled to an output of a switching section ( 1808 ) of the mixing DAC ( 1807 ). An output of the first power detector ( 1826 ) is configured to provide a channel power associated with the output signal. The first control circuit ( 1834 ) is coupled to the output of the first power detector ( 1826 ) and is configured to identify blockers based on the channel power associated with the output signal and select a frequency of the first clock signal to reduce multiplicative spur frequency translation of the blockers into the first frequency band when a desired channel is selected.