论文部分内容阅读
由声表面波延迟线、移相器及放大器可以构成高频FM振荡器.本文用三换能器声表面波延迟线和双平衡差动放大器构成振荡回路的移相器,从其动作解析可得到高灵敏度的FM振荡器,理论上可以实现线性调制.在噪声特性方面从振荡回路内放大器的白噪声求得相位噪声频谱密度,推导了CN比,SN比的变换式.上述结果表明采用本结构作为FM振荡器,只须由少量参数即可决定重要的线性及噪声特性.为了正确评价这些理论结果,与试样的实测量进行了比较,两者很一致.所以在设计FM振荡器时完全可以预估其性能.还在移相电路中设置了相位负反馈环,探讨了在不降低声表面波延迟线Q值的同时改善线性的方法,也获得了良好的结果.
By the SAW delay line, the phase shifter and amplifier can be composed of high-frequency FM oscillator.This paper uses three transducers SAW delay line and double balanced differential amplifier oscillator phase shifter form, from its action analysis Get high sensitivity of the FM oscillator, theoretically linear modulation can be achieved in terms of noise characteristics of the oscillator circuit from the white noise of the phase noise spectral density obtained, CN ratio, SN ratio derived formulas above results show that the use of this Structure As an FM oscillator, only a small number of parameters can determine the important linear and noise characteristics. In order to correctly evaluate these theoretical results, compared with the actual measurement of the sample, the two are very consistent. So in the design of the FM oscillator Can fully predict the performance.Also set in the phase shift circuit phase negative feedback loop, discussed without lowering the SAW delay line while improving the linearity of the method, also obtained good results.