Wireless transmitter bandwidth extension using dynamically varying capacitors

In this paper a technique to reduce the effect of distortion due to a band-limited front-end is proposed. The technique relies on dynamically varying the filter response at a rate that is a multiple of the symbol rate. Time-variant convolution has been used to determine a strategy to vary the filter capacitance, and two alternative circuit designs relying on switching capacitors is proposed. It has been shown that the distortion error can be reduced to 2% for a system bandwidth 7.8 times greater than the transmit front-end bandwidth.