Results 251 to 260 of about 144,951 (303)

On the Power Spectral Density of Constrained Sequences

IEEE Transactions on Communications, 2007
This paper derives a simple closed-form expression for computing the power spectral density (PSD) of constrained sequences whose constraints are characterized by a function of an ergodic Markov process specified in terms of a Mealy machine. A suitable matrix description of the stochastic behavior of the constrained sequence is used to express its ...
Cecilio Pimentel, Valdemar Cardoso da Rocha Jr.   +1 more
openaire   +1 more source

Power Spectral Density: Is It Right?

International Optical Design Conference and Optical Fabrication and Testing, 2010
We concentrate on the instrumental issues surrounding power spectral density (PSD) determination employing Fizeau interferometers. We briefly discuss the properties of an ideal calibration method and some methods that have been used previously.
John P. Lehan, Ulf Griesmann, Jiyoung Chu   +2 more
openaire   +1 more source

Estimation of Power Spectral Density by Filters

Journal of the ACM, 1964
An algorithm is presented which differs from previous methods by being more adapted for searching over wide frequency ranges and which permits the estimation of spectral density as a function of time as well as of frequency. The algorithm may offer economy, especially on smaller computers.
openaire   +1 more source

On the analogue methods for power spectral density estimation†

International Journal of Control, 1970
This paper examines an analogue method for power spectral density estimation which employs an asymmetrical modulation. The approximate expressions for the expected value and for the dispersion of the estimate thus obtained are worked out by means of simplifying hypotheses.
DI PILLO, Gianni, KOCH G., MARANO R.
openaire   +1 more source

A Power Spectral Density Analysis for Digital FM

IEEE Transactions on Communications, 1975
Except for rectangular-shaped modulating pulses, the specification of the power spectral density function (psdf) for digital FM is analytically perverse and only a few results are available in the journal literature. In this paper an analysis is presented based on the selection of an appropriate duration-limited/level-quantized approximation for the ...
openaire   +2 more sources

Sleep duration and the power spectral density of the EEG

Electroencephalography and Clinical Neurophysiology, 1986
In a sleep loss experiment with 8 subjects night sleep was restricted to either 8, 4, 2 or 0 h. The restrictions caused a strong dose-dependent increase in the duration of subsequent day sleep. Still, only a fraction of the sleep loss was recovered. Spectral analysis of the EEG demonstrated a strong dose-dependent increase also of power density.
T, Akerstedt, M, Gillberg
openaire   +2 more sources

Calculation of Doppler spectral power density functions

IEEE Transactions on Biomedical Engineering, 1992
A volume integral method for the calculation of Doppler ultrasound spectral power density (spd) functions is described. Axisymmetric flow in a circular tube with a power law velocity profile is assumed. The spd function is regarded as a probability density function for scatterer velocity, and the assumptions under which this is justified are considered.
Gepffrey K. Aldis, Rosemary S. Thompson
openaire   +2 more sources

Spectral power density calculations for pulsed Doppler

Ultrasonics, 2002
Range-gated pulsed Doppler can be used to make localized velocity measurements within a blood vessel. A spectral flow profile can be created by stepping a sufficiently small sample volume across the lumen, but no set of spectra will correspond directly to the true velocity profile.
R S, Thompson, G K, Aldis
openaire   +2 more sources

Smoothing of power spectral densities

Proceedings of the 33rd Midwest Symposium on Circuits and Systems, 2002
Power spectral estimates are smoothed using a Kalman filtering approach. The filter is used to segment the power spectral density by separating signal-dominated regions from noise-dominated regions. In doing so, it tends to preserve the fidelity for signal-related spectral peaks while smoothing the segments dominated by the noise.
openaire   +1 more source

Power spectral density of a subjective speckle pattern

Applied Optics, 1986
L'information de deplacement dans le plan sur l'objet diffusant est obtenue a partir d'une photographie speckle a double exposition focalisee/defocalisee soit par filtrage ponctuel soit par filtrage du champ ...
R K, Mohanty, C, Joenathan, R S, Sirohi
openaire   +2 more sources