  A downconversion receiver employing a switch-based N-path filter with reduced
harmonic response around the third- and fifth- LO harmonics is presented. The
N-path filter is placed in a frequency-translation feedback loop that is
effective at the 3rd and the 5th LO harmonics to mitigate harmonic
downconversion. A pulse-width-modulated LO (PWM-LO) clocking scheme is used in
the feedback upconverter to reduce the noise injected around the LO harmonic at
the input of N-path downconverter. The compression resulting from blockers
around the 3rd and the 5th LO harmonics is also suppressed as a result of
reduced harmonic response. Compensation of peak frequency shift of the N-path
response due to parasitic input capacitance is also described.
