| 摘要 |
<p>A transmitter/receiver circuit for one station of a microwave radio system comprising one signal path (10) for upconverting a signal for transmission from an antenna and a second signal path (20) for downconverting a signal received on the antenna. A single local oscillator (12) runs at twice the duplex frequency and is used to provide the signals for the upconversion and the downconversion: the oscillator signal is used directly for upconversion, and is divided by two for downconversion. A local oscillator synthesiser (17) effects the final upconversion stage of the transmitted signal and the initial downconversion stage of the received signal. Thus, the arrangement is of simple construction and requires fewer local oscillators than prior art devices. Also, the local oscillator synthesisers for two communicating radio stations can be of exactly the same, relatively simple design.</p> |
