Gain and phase mismatch effects on double image rejection transmitter

Abstract

Gain and phase mismatch effects of a double image rejection transmitter (DIRT) are examined by using error vector magnitude (EVM), image rejection ratio (IRR) and a union bound on the symbol error rate (SER). Although the DIRT has been utilised in many applications, the relationship between EVM and the IRR has not been previously reported. To analyse the relationship between EVM and IRR, the EVM functions are obtained using a complex envelope based matrix model and the IRR functions are approximated to provide insight into the gain and phase mismatch effects. Furthermore, the transmitter architecture has a lower sensitivity on both gain and phase mismatches under a proposed intermediate frequency (IF) gain condition, defined as gain condition-II. The system simulation results show that the IRR greater than 40 dBc can be achieved with 1 dB IF gain mismatch over the phase mismatch variations of 8 to 8 . The SER simulation results are also given for evaluating the system performance.