scholarly journals Instantaneous frequencies of signals obtained by the analytic signal method

2006 ◽  
Vol 27 (3) ◽  
pp. 163-170 ◽  
Author(s):  
Hideo Suzuki ◽  
Furong Ma ◽  
Hideaki Izumi ◽  
Osamu Yamazaki ◽  
Shigeki Okawa ◽  
...  
Keyword(s):  
Analytic Signal ◽  
Instantaneous Frequencies ◽  
Signal Method

FAST NONLINEAR FOURIER EXPANSIONS

2009 ◽  
Vol 01 (03) ◽  
pp. 373-405 ◽  
Author(s):  
RUI WANG ◽  
YUESHENG XU ◽  
HAIZHANG ZHANG
Keyword(s):  
Fourier Expansion ◽  
Approximation Error ◽  
Analytic Signal ◽  
Optimal Selection ◽  
Approximation Properties ◽  
Orthonormal Bases ◽  
Construction Methods ◽  
Signal Approach ◽  
Instantaneous Frequencies ◽  
Selection Of

Motivated by the analytic signal approach and general construction methods by Qian et al. (accepted by Adv. Comput. Math.), we construct a class of orthonormal bases for the real signal space [Formula: see text], which have nonconstant physically meaningful instantaneous frequencies. We develop a fast algorithm for computing the Hilbert–Fourier expansion of a given function in terms of the orthonormal bases. Moreover, we study the approximation properties of the Hilbert–Fourier expansion. A numerical example is presented to demonstrate an adaptive Fourier expansion based on an optimal selection of the parameter a in the orthonormal bases according to the approximation error.

scholarly journals Spoken digit recognition by analytic signal method

1988 ◽  
Vol 2 (2) ◽  
pp. 75-79
Author(s):  
Masashi KAWASUMI ◽  
Satoshi SEKINE ◽  
Jun-ichi KOSHI ◽  
Keiji HIRAMATSU
Keyword(s):  
Analytic Signal ◽  
Digit Recognition ◽  
Signal Method

scholarly journals Enhancing the quality of interpretation magnetic data at low latitudes

2017 ◽  
Vol 1 (T4) ◽  
pp. 105-114
Author(s):  
Hai Hong Nguyen ◽  
Nhan Thanh Nhan ◽  
Liet Van Dang ◽  
Thu Ngoc Nguyen
Keyword(s):  
Magnetic Anomaly ◽  
Hilbert Transform ◽  
Amplitude Spectrum ◽  
Data Interpretation ◽  
Analytic Signal ◽  
Magnetic Data ◽  
Low Latitudes ◽  
Reduction To The Pole ◽  
Signal Method

Magnetic anomalies are antisymmetrical and often skewed to the location of the sources, because both of the magnetization and ambient field are not directed vertically, so it’s difficult to interpret. For reducing the magnetic anomaly to a symmetrical one – this located on the source of the anomaly – people often use the reduction to the pole (RTP) where the magnetization and ambient field are both directed vertically. However, at low latitudes (an absolute inclination less than 16o30’), the amplitude spectrum of the RTP’s operator was amplified at higher frequencies (short wavelengths) can form a narrow pie-shaped; so it produces artifacts elongated along the direction of the magnetic declination. Therefore, many methods of RTP at low latitudes are given to solve this problem, but most of them are not efficiency. In this paper, we performed enhancing the quality of interpretation of magnetic data at low latitudes by some RTP methods for magnetic data at low latitudes and the analytic signal method using gradient operator and Hilbert transform. This method is applied to a model and to a real magnetic anomaly to find out the best method. Then this method was applied to enhance the quality of magnetic data interpretation in the Southern Vietnam. The result showed that the analytic signal method using Hilbert transform allowed enhancing the quality of interpretatio of magnetic data n at low latitudes is the best.

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