RADIO TRANSCEIVER

摘要

20104-8723 A radio transceiver has a transmit path comprising a first angle modulator for producing a radio transmission signal comprising a carrier wave of a first frequency modulated by a transmit message signal applied thereto, and having a receive path comprising first and second mixers for producing a resultant intermediate frequency signal from a radio reception signal applied thereto. The transceiver further comprises a second angle modulator for producing a local oscillator signal comprising a carrier wave of a second frequency modulated by the transmit message signal applied thereto. The radio transmission signal produced by the first angle modulator is applied to a local oscillator input of the first mixer and the local oscillator signal produced by the second angle modulator is applied to a local oscillator input of the second mixer. A phase shifter is so arranged that the phase of the transmit message signal applied to the first angle modulator differs from the phase of the transmit message signal applied to the second angle modulator. The respective modulation characteristics of the first angle modulator and the second angle modulator are so matched and the phase shifter has such a phase delay that substantial rejection is achieved in the second mixer of a modulation component related to the transmit message signal present in the receive path.