PERFORMANCE ANALYSIS OF CROSS-SPECTRAL DENSITY ESTIMATOR AND ITS APPLICATIONS

被引:9
作者
DAI, YS
机构
[1] Department of Electronics Engineering, Jilin University of Technology, Changchun
关键词
D O I
10.1080/00207219108925457
中图分类号
TM [电工技术]; TN [电子技术、通信技术];
学科分类号
0808 ; 0809 ;
摘要
Because of the noise and zero-drift in a pre-amplifier, it is difficult to measure a weak signal using the conventional spectral analysis method (a pre-amplifier in series with an FFT analyser). A new approach using a cross-spectral density estimator has been developed and the theoretical analysis demonstrates that the expectation of cross-spectral density is not coherent with the noise and zero-drift of the pre-amplifier; consequently, this method can ensure accurate measurement, even if the measured signal is very weak. Also, the noise in the pre-amplifier may increase the variance of cross-spectral estimation, so that the average periodogram using windowing procedures and a low noise pre-amplifier is necessary. Finally, the thermal noise of a small resistance and a nanovolt sinusoidal signal have been measured; the results are in good agreement with the theoretical values, which means that the method is feasible and accurate for measuring weak signals.
引用
收藏
页码:45 / 53
页数:9
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