Patent ID: 6735181
Filing Date: 2004-05-11
Classification: H04B

Abstract:
A wireless transceiver comprising,a transmit side having a voltage controlled oscillator (VCO) generating a radio frequency (RF) signal, the VCO having a center frequency stabilized by a reference circuit, with the center frequency swung by a modulation signal from a baseband modulation signal source, the reference circuit imposing a characteristic filter function on the RF signal producing a modulated RF output signal, and a receive side having a down-conversion mixer combining an RF input signal with the modulated RF output signal, producing an intermediate frequency (IF) signal fed to an IF amplifier and filter having a characteristic filter function operating on the IF signal, thereby producing a filtered IF signal, a detector circuit connected to receive the filtered IF signal and produce a demodulated audio signal, and a subtractor circuit connected to receive the demodulated audio signal, and a compensating filter having an output connected to the subtractor circuit and having a filter function which is the same as a composite of the characteristic filter function of the RF output signal and the characteristic filter function of the IF amplifier and filter, the input of the compensating filter arranged to receive the modulation signal and apply the complement signal thereto, thereby removing the transmit modulation from the received demodulated audio signal.