Wireless transmitter having a modified translation loop architecture

摘要

A transmitter for a wireless handset having a modified translation loop architecture. The transmitter includes a VCO that generates a modulated transmit signal having a frequency fTx, and a modulated signal source that generates a modulated LO signal with a frequency fLO. A mixer mixes the transmit signal with the LO signal to produce an IF signal having a frequency fIF. A first divider divides the LO signal frequency fLO by an integer M to generate a first comparison signal having a frequency fCF. A second divider divides the IF signal frequency fIF, after it is multiplied by an integer K, by an integer N to generate a second comparison signal having a frequency fCF. The transmit and LO signal frequencies have the relationship 1 $f_{\mathrm{Tx}}=f_{\mathrm{LO}}it\frac{\mathrm{KM}\pm N}{M}.$ A phase detector coupled to the first and second comparison signals compares the phases of the signals and outputs a control voltage to the VCO proportional to any phase differences between the signals.