Patent ID: 6516184
Filing Date: 2003-02-04
Classification: H04B

Abstract:
A transceiver having simultaneous transmission and reception capability comprising:a first local oscillator LO1 that generates a signal having a frequency fLO1; a second local oscillator LO2 that generates a signal having a frequency fLO2; a receiver that receives a receive signal having a frequency fRx, wherein fRx is one of the sum or the difference of frequencies fLO1 and fLO2, the receiver comprising an image rejection mixer that mixes frequencies fLO1 and fLO2 to generate a demodulating signal at the receive frequency fRx, and a quadrature down converter that mixes the demodulating signal with the receive signal to produce baseband â€œIâ€  and â€œQâ€  signals; and a transmitter that transmits a transmit signal having a frequency fTx, wherein fTx is equal to fRx minus a comparison frequency fCF, the transmitter comprising a voltage-controlled oscillator (VCO) that generates the transmit signal, a mixer that mixes the transmit signal with the signal from the first local oscillator LO1 to produce an IF signal having a frequency fIF, a quadrature mixer that modulates the IF signal with baseband â€œIâ€  and â€œQâ€  signals, a first divider that divides fIF by an integer M down to fCF, a second divider that divides fLO2 by an integer N down to fCF, and a phase detector that compares the phases of the signals output by the first and second dividers and outputs a control voltage to the VCO.