Efficient duty-cycle mismatch compensation in digital transmitter

This paper presents an efficient mitigation approach for duty cycle mismatch of in-phase and quadrature upconversion signals in digital transmitters. This approach is supported by a mathematical analysis of the baseband equivalent impact of duty cycle mismatch. An efficient digital pre-distortion method is proposed to eliminate the distortion impact. Simulation results show that, for both 64-QAM and 256-QAM modulation schemes, the error-vector-magnitude can be improved from -25.1dB to less than -55dB, which leaves substantial design margin for other non-idealities distorting the transmitted signal.