The Analytic Technique of Band-Pass Signal
He Lingsong Wu Ya Yang Shuzi (Department of Mechanical Engineering, Huazhong University of Science and Technology Wuhan, 430074)
In the process of practical signal, a kind of signal which is concentrated in a narrow band frequency domain may be encountered. To obtain its fine frequency structure, You must use a special processing technique, such as ZOOM-FFT to analyse it. But this needs a lot of sample data and a large amount of computation. To solve this problem, the relation between the sample frequency and the spectrum mixing effect of the sampled signal is studied. When the sample frequency is larger than twice the width of the signal band and less than twice the highest frequency component in the signal, the spectrum mixing effect still exists, sometimes with its shape unchanged, but only moving distance in the frequency axis. Upon this basis, a new sample formula for band-pass signal is proposed, and a precise algorithm of its spectrum analysis is designed. The problem of signal reconstruction of band-pass sampled signal is also discussed in this paper.
【Fund】： 国家自然科学基金;; 华中理工大学基础研究基金