Study on variable frequency SAW filter and its applications

介绍了宽带声表面波谐振器的发展及其在变频滤波器和振荡器中的应用，旨在采用高度复杂的无线电通信系统。首先，提出了一种抑制宽带表面声波谐振器杂散响应的系统设计技术。在此基础上，研制了包括声表面波谐振器在内的可变频带消除滤波器。结果表明，该滤波器可实现具有低相位噪声特性的UHF变频振荡器。最后，研究了基于递归结构的UHF有源滤波器。实验还表明，所开发的自整定技术实现了滤波器控制器的良好性能。

It is described that the development of wideband SAW resonators and their applications to variable frequency filters and oscillators aiming at adopting highly sophisticated radio communication systems. At first, a systematic design technique was proposed for suppressing spurious responses of wideband surface acoustic wave (SAW) resonators. Then, the variable frequency band elimination filters including the SAW resonators were developed. It was shown that the filter enables us to realize an UHF variable frequency oscillators with low phase noise property. Finally, active filter in UHF range based on recursive architecture was investigated. It is also shown that the developed self-tuning techniques implemented the controller of the filter works fine.