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本文提出了一种从噪声中检测周期信号的周期和功率谱的新方法,即使用互谱进行同步相加的方法,并从理论和实验上进行了研究。具体地说,该方法是在保持一定时间延迟的条件下,从掩埋在噪声中的周期信号上进行两次取样,计算两次取样之间的互谱,再对互谱进行多次同步相加。本方法与以前使用触发脉冲的功率谱法不同,它的一个特点是不需要触发脉冲。根据理论分析可知,用上述方法得到的互谱就等于周期信号的功率谱被旋转了一个同时间差和频率的积成比例的相位。本文还分别以掩埋在白噪声中的二个正弦波和由掩埋在白噪声中的短周期M序列信号构成的周期噪声信号为对象进行了实验验证。结果表明,本方法对高精度地检测噪声中的周期信号的周期和功率谱是有效的。
In this paper, we propose a new method to detect periodicity and power spectrum of periodic signals from noise, that is, the method of using the cross spectrum to add synchronization, and study the theory and experiment. Specifically, the method is to sample twice from the periodic signal buried in the noise under the condition of keeping a certain time delay, to calculate the cross spectrum between the two samples, and then to synchronously add the cross spectrum to each other . This method is different from the previous power spectrum method that uses the trigger pulse. One of the features of this method is that no trigger pulse is required. According to theoretical analysis, the cross spectrum obtained by the above method is equal to the periodic signal power spectrum is rotated by a time difference and the frequency of the product of the proportional phase. In this paper, two sinusoidal waves buried in white noise and periodic noise signals composed of short-period M-sequence signals buried in white noise are respectively validated by experiments. The results show that the proposed method is effective in detecting periodic and power spectra of periodic signals in noise with high accuracy.