基于X频段深空应答机的石英晶体性能需求

根据X频段深空应答机载波锁相环路的实际应用,分析了应用于压控晶体振荡电路的石英晶体性能需求,给出了石英晶体存在频率跳变的原因和对X频段深空应答机的影响,并提出了对石英晶体的筛选方法和判据：对石英晶体进行激励功率依赖性扫描,在激励功率10～300 μW内,频率跳点小于0.2脉冲/min,曲线重复性小于0.4脉冲/min,且石英晶体电老练试验前后的激励功率依赖性曲线相似.将该筛选方法和判据应用于嫦娥三号X频段深空应答机研制中,结果表明该措施可行、有效.

Performance Requirements of Quartz Crystal for X-Band Deep Space Transponders

The performance requirements of quartz crystal used in VCXO （Voltage Controlled Crystal Oscillator） are analyzed for applications of carrier PLL （Phase-Locked Loop） in X-band deep space transponders. The reasons for frequency hopping of quartz crystal are provided together with the impact on X-band deep space transponders. Screening method and judgment criteria are proposed for quartz crystal. Specifically, frequency hopping should be under 0.2 ppm and curve repeatability should be under 0.4 ppm over the drive level of 10 μW to 300 μW in DLD （Drive Level Dependency） scan. In addition, the DLD curves should resemble each other before and after burn-in experiments. The method and criteria are validated in research and development of X-band deep space transponders for Chang＇e-3 lunar probe.