Doppler power spectrum from a Gaussian sample volume

Ultrasonics ◽  
2000 ◽  
Vol 37 (9) ◽  
pp. 623-632 ◽  
Author(s):  
Carlos A.C. Bastos ◽  
Peter J. Fish ◽  
Robin Steel ◽  
Francisco Vaz
Keyword(s):  
Power Spectrum ◽  
Sample Volume ◽  
Doppler Power ◽  
Gaussian Sample

Modeling of Doppler Signal considering Sample Volume and Field Distribution

1989 ◽  
Vol 11 (3) ◽  
pp. 175-196 ◽  
Author(s):  
Yeong M. Kim ◽  
Song B. Park
Keyword(s):  
Power Spectrum ◽  
Field Distribution ◽  
Amplitude Spectrum ◽  
Pulse Length ◽  
Sample Volume ◽  
Doppler Signal ◽  
Intersection Angle ◽  
Transmitted Pulse ◽  
Beam Geometry ◽  
Doppler Power

The ultrasound Doppler amplitude spectrum for a single scatterer and the power spectrum for multiple scatterers were calculated in terms of the echo signal from scatterers crossing the sample volume, defined by the transmitted pulse and the diffracted field distribution for cw. The observation time for the Doppler signal is also considered. Statistical parameters such as mean and variance of the Doppler power spectrum are studied as continuous functions of the intersection angle between the beam axis and the flow direction, the pulse length and the viewing position. The derived equations are valid whether the transit time is governed by the pulse length, or beam geometry, or both. It is shown that the Doppler power spectra calculated by the proposed model and by the Doppler signal obtained from field theory are in good agreement. It is also shown that, when the Doppler signal broadening due to the transmitted pulse and beam geometry is constant without regard to the intersection angle, the degree of spread of the velocity distribution can be estimated from the variance of the Doppler power spectrum measured by the Doppler system once the intersection angle is known.

scholarly journals An Estimator for Weather Radar Doppler Power Spectrum via Minimum Mean Square Error

2021 ◽  
pp. 1-16
Author(s):  
Eiichi Yoshikawa ◽  
Naoya Takizawa ◽  
Hiroshi Kikuchi ◽  
Tomoaki Mega ◽  
Tomoo Ushio
Keyword(s):  
Power Spectrum ◽  
Mean Square Error ◽  
Minimum Mean Square Error ◽  
Weather Radar ◽  
Mean Square ◽  
Doppler Power

On the Doppler power spectrum at the mobile unit employing a directional antenna

2001 ◽  
Vol 5 (1) ◽  
pp. 13-15 ◽  
Author(s):  
Chang Qing Xu ◽  
Choi Look Law ◽  
S. Yoshida
Keyword(s):  
Power Spectrum ◽  
Directional Antenna ◽  
Mobile Unit ◽  
Doppler Power

scholarly journals A Novel Simulation Modeling Method and Hardware Implementation for Doppler Power Spectrum of LEO Satellite Based on Error Compensations by Parting Sinusoid with Random AOA and Correlation Piecewise Convergence

Electronics ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 65
Author(s):  
Wenliang Lin ◽  
Yaohua Deng ◽  
Ke Wang ◽  
Zhongliang Deng ◽  
Hao Liu ◽  
...  
Keyword(s):  
Power Spectrum ◽  
Simulation Modeling ◽  
Frequency Dispersion ◽  
Signal Propagation ◽  
Low Earth Orbit ◽  
Set Partitioning ◽  
Angle Of Arrival ◽  
Sixth Generation ◽  
Doppler Power ◽  
Leo Satellite

Low Earth Orbit (LEO) Satellite Internet Network (LEO-SIN) is a promising approach to global Gigabit per second (Gbps) broadband communications in the coming sixth-generation (6G) era. This paper mainly focuses on the innovation of accuracy improvement of simulation modeling of the Doppler Power Spectrum (DPS) of satellite channels in LEO-SIN. Existing DPS modeling methods are based on Rice’s Sum-of-Sinusoids (SOS) which have obvious modeling errors in scenarios with main signal propagation paths, asymmetrical power spectrum, and random multi-path signals with a random Angle of Arrival (AOA) in LEO-SIN. There are few state-of-art researches devoted to higher accuracy of DPS modeling for simulation. Therefore, this paper proposes a novel Random Method of Exact Doppler Spread method Set Partitioning (RMEDS-SP). Distinct from existed researches, we firstly model the DPS of LEO-SIN, which more accurately describes the characteristics of frequency dispersion with the main path and multi-path signals with random AOA. Furthermore, piecewise functions to the Autocorrelation Function (ACF) of RMEDS-SP is first exploited to converge the modeling error supposition with time by periodic changes, which further improve the accuracy of the DPS model. Experimental results show that the accuracy of DPS in our proposed model is improved by 32.19% and 18.52%, respectively when compared with existing models.

scholarly journals Effects of Narrow Beam Phased Antenna Arrays over the Radio Channel Metrics, Doppler Power Spectrum, and Coherence Time, in a Context of 5G Frequency Bands

2021 ◽  
Vol 11 (21) ◽  
pp. 10081
Author(s):  
Brian J. Sánchez ◽  
David H. Covarrubias ◽  
Leonardo F. Yepes ◽  
Marco A. Panduro ◽  
Elizvan Juárez
Keyword(s):  
Power Spectrum ◽  
Antenna Array ◽  
Antenna Arrays ◽  
Communication Systems ◽  
Radio Channel ◽  
Coherence Time ◽  
Narrow Beam ◽  
Frequency Bands ◽  
Phased Antenna Array ◽  
Doppler Power

With the arrival of 5G wireless communication systems, there has been increased interest in exploring higher frequency bands above 6 GHz, up to millimeter-wave frequencies. Radio wave propagation at these higher frequencies can suffer from substantial Doppler impairments. The linear dependency of Doppler shifts with carrier frequencies make them challenging to use in high-mobility 5G cellular scenarios. Therefore, the Doppler power spectrum (DPS) characteristics and radio channel coherence time (CT) of the received signals are of great importance for 5G wireless systems. In this way, this paper presents the effects of a narrow beam phased antenna array in reducing the DPS (due to user movement) and, simultaneously, increasing the coherence time (CT). Functional and complete descriptive assessments of beamwidths versus the DPS and CT, through different elements and geometries of the phased antenna array, are analyzed. Moreover, in terms of CT and the DPS, better performance on the 5G cellular scenarios was obtained.

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