Modelling of IQ Impaired Zero-IF Transceivers

Zero-IF (Direct-Conversion) Quadrature modulator is comprised of two mixers separated by [90][/o] phase. Zero-IF Quadrature modulators and demodulators suffer from the Inphase-quadrature phase (IQ) imbalances between the analog processing components in the I/Q paths. The gain and phase errors in the local oscillators and the filters in I/Q paths account for the I/Q errors or impairments. IQ impairments in Quadrature modulator can degrade the quality of the transmitted signal during the modulation process, resulting in degraded error vector magnitude (EVM) at the receiver, which in turn degrades bit error rate (BER).

An introduction to system modelling of IQ impaired Quadrature Modulator and Demodulator is presented in my **broken link removed**.