Detection Method of Signal Characters Based on Normalized Quadratic Spectrum in Timeª²Frequency
Domain
Yu Fan£¬Qin Zheng
£¨School of Electronics and Information Engineering£¬Xi'an¡¡Jiaotong¡¡University£¬Xi'an
710049£¬China£©
Abstract£ºThe traditional signal detection method based on Fourier transform has no time
resolution in the frequency domain and the detection method based on wavelet transform
cannot characterize the slowª²varied signal£® Focusing on the problem mentioned above£¬
a new detection method based on normalized quadratic spectrum £¨NQS£© in the timeª²frequency
domain is proposed£® Firstly£¬ Fourier transform of the original signal¡¯s amplitude
spectrum is performed in the frequency domain£¬ and then NQS is obtained by normalizing
the transformation of amplitude£® Afterwards£¬ the signal detection is performed based
on the obtained NQS£® The supplementary zero or adding window methods£¬ etc£® can be
used simultaneously to prevent from spectrum leakage£® It is proved that NQS can reflect
both the frequency and the time characters of the signal£® This merit of NQS can overcome
some pitfalls of traditional detection methods£® The validity of the proposed method is
verified when it is applied to the character expression of the pole and oil pipeline¡¯s
conductive signal£®
Keywords£ºsignal character detection£» timeª²frequency domain£» normalized quadratic
spectrum