Direct-conversion transmitter with resistance to local oscillator pulling in non-constant envelope modulation systems

Summary form only given, as follows. This work studies the LO pulling effect associated with a direct-conversion transmitter (DCT) in non-constant envelope modulation systems. The relevant theory provides an analytical model to predict DCT signal quality degradation due to pulling effect. To mitigate it, a novel approach for reducing FM distortions by a combination of second-point VCO modulation and inner self-injection is presented. The improved performance is verified by realizing a QPSK transmitter for cdma20001× applications.