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随着无线通信技术的应用和发展,对高质量的高频信号源要求日益迫切,这主要表现在对频率的稳定度和准确度的要求越来越高,并且希望能方便地调整频率。常见的信号产生方法很难满足这些要求,如石英晶体振荡器可以达到很高的频率稳定度,但是调整频率困难;LC振荡器调整频率比较容易,但是频率稳定度和精度方面又达不到要求。锁相环频率合成技术则可以同时满足两方面的要求,而压控振荡电路的设计是锁相环最为关键的一个环节,决定着锁相环的频率大小、频带的宽度、稳定度。
With the application and development of wireless communication technology, the requirements for high-quality high-frequency signal sources are increasingly urgent. This is mainly manifested in that the requirements on the stability and accuracy of the frequency are getting higher and higher, and the frequency is expected to be conveniently adjusted. Common signal generation methods are difficult to meet these requirements, such as quartz crystal oscillator can achieve high frequency stability, but difficult to adjust the frequency; LC oscillator to adjust the frequency easier, but the frequency stability and accuracy are not met . PLL frequency synthesis technology can meet both requirements at the same time, and voltage-controlled oscillator circuit design is the most critical phase-locked loop, determines the frequency of the PLL, the frequency band width, stability.