Driscoll M M
Westinghouse Electron. Syst. Group., Baltimore, MD.
IEEE Trans Ultrason Ferroelectr Freq Control. 1993;40(4):427-30. doi: 10.1109/58.251295.
Through the use of N series-connected quartz crystal resonators in an oscillator circuit, a 10 log N reduction in both flicker-of-frequency noise and white phase-noise (floor) levels has been demonstrated. The reduction in flicker noise occurs as a result of the uncorrelated short-term frequency instability in each of the resonators, and the reduction in noise floor level is a simple result of the increase in net, allowable crystal drive level. This technique has been used in 40-, 80-, and 100-MHz AT-, BT-, and SC-cut crystal oscillators using low flicker-of-phase noise modular amplifier sustaining stages, and four series connected crystals. Total (four crystal) power dissipations of up to 30 mW have been utilized. State-of-the-art, flicker-of-frequency noise levels have been obtained with noise-floor levels (80 MHz) as low as -180 dBc/Hz. Four- to five-fold reduction in acceleration sensitivities has been determined.
通过在振荡器电路中使用 N 个串联的石英晶体谐振器，已证明频率闪烁噪声和白相位噪声（本底）水平均降低了 10 log N。频率闪烁噪声的降低是由于每个谐振器中不相关的短期频率不稳定性所致，而本底噪声水平的降低则是净允许晶体驱动电平增加的简单结果。该技术已用于 40 MHz、80 MHz 和 100 MHz 的 AT 切、BT 切和 SC 切晶体振荡器，这些振荡器使用低相位闪烁噪声模块化放大器维持级以及四个串联晶体。已利用高达 30 mW 的总（四个晶体）功耗。已获得了最先进的频率闪烁噪声水平，其本底噪声水平（80 MHz）低至 -180 dBc/Hz。已确定加速度灵敏度降低了四到五倍。
