Schoolof Physics, University of Western Australia, Crawley, W.A., Australia.
IEEE Trans Ultrason Ferroelectr Freq Control. 2010 May;57(5):1034-8. doi: 10.1109/TUFFC.2010.1515.
A cryogenic sapphire oscillator (CSO) has been implemented at 11.2 GHz using a low-vibration design pulsetube cryocooler. Compared with a state-of-the-art liquid helium cooled CSO in the same laboratory, the square root Allan variance of their combined fractional frequency instability is sigma(y) = 1.4 x 10(-15)tau(-1/2) for integration times 1 < tau < 10 s, dominated by white frequency noise. The minimum sigmay = 5.3 x 10(-16) for the two oscillators was reached at tau = 20 s. Assuming equal contributions from both CSOs, the single oscillator phase noise S(phi) approximately -96 dB x rad(2)/Hz at 1 Hz set from the carrier.
采用低振动设计脉冲管致冷器实现了 11.2GHz 的低温蓝宝石振荡器（CSO）。与同一实验室中最先进的液氦冷却 CSO 相比，它们的组合分数频率不稳定性的平方根 Allan 方差为 sigma(y) = 1.4 x 10(-15)tau(-1/2)，积分时间为 1 < tau < 10s，主要由白噪声频率主导。两个振荡器的最小 sigmay = 5.3 x 10(-16)在 tau = 20s 时达到。假设两个 CSO 的贡献相等，从载波处设置的 1Hz 处的单个振荡器相位噪声 S(phi)约为-96dB x rad(2)/Hz。
