| 摘要 |
Transceivers for use in time division telecommunication units like mobile phones and base stations can be produced at lower costs by, in a transmitting mode, switching the direct digital synthesizer (DDS 24 ) driven phase locked loop (PLL 10 - 15 ) into a modulating state and supplying a modulation signal to the DDS and switching in the PLL a first filter ( 12 ) allowing the generation of an improved modulated signal, and by, in a receiving mode, switching the DDS driven PLL into an oscillating state and supplying a non-modulation signal to the DDS and switching in the PLL a second filter ( 13 ) allowing demodulation with reduced phase noise. A transmitter part ( 2 ) and a non-transmitter part ( 4,6 ) share a single DDS driven PLL, based upon the basic idea of using important parts in low cost transceivers for both modes, instead of using different parts for different modes, and achieve a good performance.
|
