短期频率稳定度时域测量方法及实现

【作者】 曾铮；

【导师】 刘镰斧；

【作者基本信息】 电子科技大学 ， 通信与信息系统， 2008， 硕士

【摘要】 随着现代通信技术的发展,在很宽的频率范围内对非标准信号需要具有较高的测量精度。然而在测量精度与仪器的成本,复杂程度和应用条件之间存在着矛盾,具有高精度,低成本,和简单结构的测量仪器备受欢迎。我们的主要目的也就是研究满足这样一种要求的测量系统,具有较高测试精度,较宽测试范围,同时系统结构简单,成本较低,方便应用的短期频率稳定度测试仪。本论文针对目前国内外短期频率稳定度的测量技术的发展,对这个领域进行了探索和初步的研究:首先简要介绍了频率源输出噪声模型,及其在时域频域不同的表示形式;短期频率稳定度的物理意义及其表征,包括在时域和频域的表征,以及这两种表征之间的联系和换算方法;接着阐述了阿伦方差的定义和计算方法;介绍了短期频率稳定度时域频域测量的常用方法,主要介绍了差频周期法,频差倍增法等;以及这些方案在电路中引入相位噪声的情况。然后根据具体给出的指标,我们用一个具体的实例来说明测量短期频率稳定度的方法和过程。选用频差倍增法,分三个部分:频率发生部分,频差倍增部分和混频调制部分,设计完整的硬件电路,整机自校精度达到10 ?1 3/s量级。并对其噪声性能做了比较详细地说明和分析。针对频差倍增方案实现中存在的问题,提出改进方案;选用另一种短期频率稳定度的时域测量方法,双混频时差法再次实现短稳的测量,详细论述了双混频方案的测量原理,并对公共源引入噪声的影响做了说明和推导;实现硬件电路;在软件设计上,设计了相应保障其测量计算可信度的算法。最后总结和比对这两种不同的方案,根据测试结果分析其优缺点,指出各自适用的范围。更多还原

【Abstract】 Nowadays, for the development of the communication technology, high precision measurement of the nonstandard signal were needed in very wide frequency spectrum. But it was a contradiction between the high precision and the cost of instrument, so the instruments of high precision, low cost and simple structure were very popular. The aim of us is to work over this system accord the above, the short-term frequency stability measurement system accord with high precision, simple structure, low cost and convenient to use.Research had been done in this article:First, the output noise model of frequency source and its behave form had been instructed; the physical meaning of the short-term frequency stability and its performance in the time domain and frequency domain. Then the measurement method, main the frequency difference period measurement, the frequency difference multiply measurement had been instructed.Second, an example of given target which use the frequency difference multiply measurement had been performed. This project contains three main parts: the part of frequency produce, the part of frequency difference multiplier, the part of frequency mix and modulation. The circuits had been realized and the precision achieve 10 ?1 3/sin time domain. Then the noise performance had been discussed in this article. Third, because of the shortage of the project mentioned above, a new realization, the double mixer time difference measurement had been brought forward. The measurement theory and the noise performance had been discussed. The circuit and the software had been realized.Last, the two realization had been summarized and these application range had been discussed.更多还原