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近年来,美国雷声公司已经有研制300～600MHz可军用的声表面波振荡器的课题;此种振荡器在频率调节能力和稳定性两方面均达当代最高水平。本文不讨论这种振荡器的详细用途。对它的要求一般为:(1)噪声本底必需至少为-160dBc/Hz;(2)振动灵敏度至少应与AT切体波器件一样好;(3)振荡器频率应能在大致±10ppm频率窗内进行调节并加以保持。在某些情况还要求加热时间小于3分钟。在满足这些要求方面,雷声公司已取得明显进展。本文将对这种进展加以讨论。在频谱纯度方面,文中讨论了二个题目:其一是低噪声放大器。实验证明,当它与310MHz声表面波谐振器联用时,噪声本底可达-176dBc/Hz。其二主要讨论了外部振动对噪声边带的影响。研制声表面波振荡器最重要的方面之一就是它的频率调节能力。利用金衬微调技术被证实既适用于延迟线也适用于谐振器。文中给出了实验结果,也讨论了在焊封过程中产生频移(约100ppm数量级)这一复杂情况。但已提出一种外部牵引频率技术来重调频率。在很多应用场合要求用恒溫箱以保持常温,于是就要求快速加热,而给出的数据要能显示出3分钟加热周期的频率稳定度。最后,除上述要求外,还要求声表面波振荡器的长稳保持在～1ppm/年的水平。利用提供的数据来确定冷焊密封在TO-8型外壳中的器件的基本老化率,同时也示出微调器件以及低振动灵敏度器件的变化率。
In recent years, the United States Raytheon companies have developed 300 ~ 600MHz military SAW oscillator issues; such oscillator in the frequency regulation ability and stability both reached the highest level of contemporary. This article does not discuss the detailed use of this oscillator. The requirements for it are generally: (1) the noise floor must be at least -160dBc / Hz; (2) the vibration sensitivity should be at least as good as AT-cut bulk wave devices; (3) the oscillator frequency should be at a frequency of approximately ± 10ppm Adjust the window and keep it. In some cases also requires heating time is less than 3 minutes. Raytheon has made significant progress in meeting these requirements. This article will discuss this progress. In terms of spectral purity, two topics are discussed in the paper: One is a low-noise amplifier. Experiments show that when it is combined with the 310MHz SAW resonator, the noise floor can reach -176dBc / Hz. The second part mainly discusses the influence of external vibration on the noise sideband. One of the most important aspects of developing a SAW oscillator is its frequency regulation capability. The use of gold lining trimmer technology has proven to be suitable for both delay lines and resonators. The experimental results are given in the paper, and the complicated situation of frequency shift (about 100 ppm order of magnitude) is also discussed in the welding process. However, an external traction frequency technique has been proposed to re-tune the frequency. In many applications require constant temperature incubator to maintain room temperature, so it requires rapid heating, and given the data to show the 3-minute heating cycle frequency stability. Finally, in addition to the above requirements, it is also required that the SAW oscillator be maintained at a level of ~ 1 ppm / year. The data provided were used to determine the basic burn-in rate of devices cold-welded in the TO-8 enclosure, as well as the rate of change of trim devices and low-vibration-sensitivity devices.