摘要
在短波通信设备中,当预选器工作时,会有载波信号泄漏到后选器中;反之,当后选器工作时,也存在载波信号泄漏到预选器中。如果预/后选器隔离度低,这些泄漏的信号会和传输信号一同被放大,对通信设备性能造成不利影响。针对这一问题,提出了一种全方位提高短波预/后选器隔离度的设计方案。讨论了保护电路的设计以及PCB排版时应注意的接地问题。测试结果表明,预/后选器的隔离度达到60 d B以上,有效地解决了因载波泄漏导致通信设备性能不佳的问题。
In the shortwave communication device,when the pre-selector is operating,a carrier signal can leak into the postselector; on the other hand,when the post-selector is working,a carrier signal leaks into the pre-selector as well.If the pre/post selector isolation is low,these leaked signals can be amplified together with the transmitted signal,becoming strong enough to damage the performance of the communication device. In order to solve this problem,a design scheme is proposed to improve the isolation of shortwave pre/post selector.The protection circuit design and grounding problem in PCB layout are discussed.The test results show that the isolation of the pre/post selector can reach more than 60 d B.The weak performance problem of communication device caused by the carrier leakage can be effectively solved in this way.
出处
《无线电工程》
2017年第12期79-82,共4页
Radio Engineering
