Results 251 to 260 of about 3,095,615 (291)

Instantaneous Frequency Estimation and Localization

2016
In many applications, a critical feature of a nonstationary signal is provided by its instantaneous frequency (IF), which accounts for the signal spectral variations as a function of time. This chapter presents methods and algorithms for the localization and estimation of the signal IF using timefrequency (t, f) based methods.
El-Jaroudi, A., Emresoy, M.K., Stanković, L.J., Hussain, Z.M., Boashash, B., O'Shea, P.J., Barkat, B., Sucic, V., Lerga, J., Rankine, L.J., Djurović, I., Simeunović, M., Djukanović, S., Ristic, B.   +13 more
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Instantaneous frequency and time-frequency distributions

IEEE International Symposium on Circuits and Systems, 2003
A discussion of instantaneous frequency from the point of view of joint time-frequency distributions is presented. From this perspective, instantaneous frequency is the average frequency at a particular time. This view forces the consideration of the standard deviation of instantaneous frequency at a given time.
L. Cohen, C. Lee
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Instantaneous frequency: Discussion

The Leading Edge, 1992
In Properties of instantaneous seismic attributes (July 1991 TLE), R.E. White shows graphically the instantaneous frequency can be negative. This property of the instantaneous frequency is very interesting, especially when we keep in mind the fact that an analytic signal associated with a real signal contains no negative-frequency components.
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Instantaneous frequency measurement

Medical Electronics & Biological Engineering, 1963
A method is outlined for obtaining an indication of instantaneous frequency by a computation of the reciprocal of the time for one period. This is accomplished by the discharge of a condenser through an element having current proportional to the square of the voltage. The square law element consists of a biased diode network.
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Multiple motions from instantaneous frequency

Proceedings 1992 IEEE Computer Society Conference on Computer Vision and Pattern Recognition, 2003
The measurement of multiple velocities using phase-based methods is discussed. In particular, phase gradients (instantaneous frequency) from different bandpass channels (quadrature filter outputs) are used to estimate multiple image velocities in a single neighborhood. The approach is similar to that of M. Shizawa and K.
Keith Langley, David J. Fleet, Tim J. Atherton   +2 more
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A Low Frequency Meter with Instantaneous Response

IEEE Transactions on Biomedical Engineering, 1979
A practical method is described for instantaneous frequency measurement by computation of the reciprocal of the time interval between two events. Use is made of inexpensive integrated circuits.
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Comments on instantaneous frequency

SEG Technical Program Expanded Abstracts 1991, 1991
Instantaneous frequency is defined, like angular velocity in rotational physics, as the derivative of the instantaneous phase (or angle). An alternative frequency measure is the change in instantaneous phase over a time interval divided by that time interval.
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Algorithmic Measurement of Digital Instantaneous Frequency

IEEE Transactions on Communications, 1976
This paper presents an algorithmic method for measuring the instantaneous frequency of a uniformly sampled FM signal. The measured parameter, termed digital instantaneous frequency, is defined in a manner similar to that used to describe frequency-modulated, continuous-time signals.
Hussein S. El-Ghoroury, Someshwar C. Gupta   +1 more
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Interpretation of Instantaneous Frequencies

American Journal of Physics, 1974
The relation between instantaneous frequencies and Fourier components of a time-dependent signal is examined. Examples are given in which large excursions of the instantaneous frequency do not correspond to any Fourier components, and in which Fourier components are not manifest in the instantaneous frequencies.
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Microprocessor-based instantaneous frequency meter

Electroencephalography and Clinical Neurophysiology, 1981
Abstract An instantaneous frequency meter employing a 6502 microprocessor (Rockwell AIM 65) is described. it features low cost, linearity, and flexibility, allowing software control of sensitivity.
S, Iscoe, R A, Young
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