Improved mixer IIP2 through dynamic matching

With the increasing demand for multi-band/multi-mode wireless device functionality, there is a need for a cost-effective receiver which circumvents the overhead associated with a traditional super-heterodyne receiver. The direct-conversion receiver (DCR) shown is one possible solution. Unfortunately, RF performance of the architecture is severely limited by second-order nonlinearities which in the past have narrowed its application to low-spec transceivers. This is due to limited selectivity preceding the downconversion mixer which allows any two signals inside of the preselector bandwidth, whose difference in frequency is less than the signal bandwidth, to generate a distortion component at baseband through a second-order nonlinearity. To resolve this issue, dynamic matching is utilized to mitigate circuit imbalances by frequency translating or frequency spreading the undesirable spectral components out of or within the frequency band of interest.