一种钽酸锂压控振荡器的设计与实现

该文使用具有低电容比、宽调谐范围的钽酸锂晶体设计了一巴特勒共基低相位噪声压控振荡器,此设计在寻求高有载品质因数QL的同时保持了振荡器的输出功率。使用的钽酸锂晶体的无载品质因数Q0约为1.24×103,其频率为10.727MHz。设计出的巴特勒振荡器QL≈33%Q0,输出功率约为11dBm。不加压控的情况下,实际测得该振荡器的相位噪声结果为-85dBc/Hz@10 Hz和-145dBc/Hz@1kHz。在此基础上,增加一变容二极管作为压控元件设计了钽酸锂压控振荡器,在2~10 V范围内,测得控制电压压控斜率约为86.6×10-6/V,相位噪声测试结果优于-82dBc/Hz@10Hz和-142dBc/Hz@1kHz,实现了具有宽调谐范围的低相位噪声钽酸锂振荡器的设计。

Design and Implementation of a Lithium Tantalate Voltage Controlled Oscillator

A wide tuning range Butler common base low phase noise voltage controlled oscillator is designed by using the lithium tantalate crystal with low capacitance ratio and wide tuning range in this paper.A compromise between seeking high loaded quality factor QL and maintaining oscillator output power is considered in this design. The unloaded quality factor Q0 of Lithium Tantalate crystal is about 1.24×103,and its frequency is about 10.727 MHz. The loaded quality factor QL of the designed Butler oscillator is about 33% of Q0 and the output power is 11 dBm. The measured phase noises are -85 dBc/Hz@10 Hz and -145 dBc/Hz@1 kHz respectively without adding voltage control. After adding a varactor as the voltage control component, a Lithium Tantalate voltage controlled oscillator is designed. Its voltage controlled slope are 86.6×10-6/V and its measured phase noise results are better than -82 dBc/Hz@10 Hz and -142 dBc/Hz@1 kHz when the control voltage range is from 2 V to 10 V. The Lithium Tantalate voltage controlled oscillator design with wide tuning range and low phase noise has been realized.