Encyclopedia

Doppler shift

Also found in: Dictionary, Medical, Wikipedia.

Doppler shift

See Doppler effect.
Collins Dictionary of Astronomy © Market House Books Ltd, 2006

Doppler shift

[′däp·lər ‚shift]
(physics)
The amount of the change in the observed frequency of a wave due to Doppler effect, usually expressed in hertz. Also known as Doppler frequency.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

Doppler shift

Doppler shift
Doppler effect in moving receiver.
In airborne Doppler radar, a transmitter which, by means of a directional antenna, radiates energy toward the ground. This results in a situation in which both the transmitter and the receiver are moving relative to the ground; consequently the original frequency is changed twice. The difference between transmitted and received frequencies is known as the Doppler shift and is very nearly proportional to the relative motion between the aircraft and the ground along the direction of the radar beam. A moving target will cause the frequency of the echo signal to increase if it is approaching the radar or decrease if it is receding from the radar. Since the Doppler frequency shift is proportional to radial velocity, a radar system that measures such a shift in frequency can also provide the radial velocity of a target. The Doppler frequency shift also is used to separate moving targets from stationary ones even when the undesired clutter power might be much greater than the power of echo from the targets. Also called the Doppler effect.
An Illustrated Dictionary of Aviation Copyright © 2005 by The McGraw-Hill Companies, Inc. All rights reserved

Doppler effect

The change in electromagnetic frequency that occurs when the source of the radiation and its observer move toward or away from each other. The faster they come together, the higher the frequency. The faster they move away, the lower the frequency. Discovered by Austrian physicist Christian Doppler (1803-1853), this condition has a great effect on low-earth orbit (LEO) satellites as they weave towards and away from the earth. See Doppler radar.
Copyright © 1981-2025 by The Computer Language Company Inc. All Rights reserved. THIS DEFINITION IS FOR PERSONAL USE ONLY. All other reproduction is strictly prohibited without permission from the publisher.
Mentioned in
References in periodicals archive
This is because the influence of Doppler Effect is getting weaker with the decreasing bandwidth which is the Delay Spread: Frequency Selective Fading and Doppler Shift. Based on the calculation, the higher the bandwidth, the stronger the Doppler Spread: Frequency Selective Fading and the Doppler Shift.
Performance Analysis of User Speed Impact on IEEE 802.11ah Standard affected by Doppler Effect
The parallel numbers of resampling units are controlled on frame-by-frame basis according to the measured Doppler shift mean and deviation.
Parallel Resampling of OFDM Signals for Fluctuating Doppler Shifts in Underwater Acoustic Communication
The Doppler shift is determined by the user terminal access Elevation angel and the satellite tangential velocity, so Doppler shift in each LEO satellite channel multi-path can be approximated equal.
Multi user interference cancellation in satellite to ground uplink system based on improved WPIC algorithm
where [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII], denotes the maximum Doppler shift due to the transmitter (i = 1) or receiver (i = 2) which moves at velocity [v.sub.i] and carrier wavelength A.
Improvement in channel estimation and error rate performance in mobile cooperative OFDM systems with intercarrier interference
Under a Rayleigh channel model, [P.sub.c] is calculated at different SNRs and different values of the Doppler shift of the channel.
Effect of wireless channels on detection and classification of asthma attacks in wireless remote health monitoring systems
A new method for estimating the Doppler shift and time delay of the overlapping echoes was presented by Qi et al.
Statistical characteristics of the multi-path time delay and Doppler shift of a radar wave propagating through the ionosphere
Doppler shift caused by skin acceleration was recorded during each procedure.
Effects of upper extremity movements on sternal skin stress
In Sections 3-4, the analytical formulas for Doppler shift and bandwidth are derived when the effects of large-scale waves shadow and curvature are also taken into account.
Microwave doppler spectra of sea echoes at high incidence angles: influences of large-scale waves
The spacecraft made it half way across the solar system before engineers discovered a potentially fatal flaw in the communications system caused by dynamic signal distortions due to Doppler shift.' This problem limited the data bandwidth available to the probe, and its severity required engineers to alter the flight path of the spacecraft to work around the issue.
Lessons from nature in testing RF equipment
The Doppler shift estimations could be used for prerecorded vehicle pattern processing and for more complex learning algorithm solutions [3].
Acoustic noise pattern detection and identification method in Doppler system
This frequency shift is called a Doppler shift. It is important to mention that the particles conveyed by a fluid flow to be measured must be big enough to scatter sufficient light for signal detection but small enough to follow the flow faithfully [Jafarzadeh, 2009].
The use of laser Doppler flowmetry in paediatric dentistry
Copyright © 2003-2025 Farlex, Inc Disclaimer
All content on this website, including dictionary, thesaurus, literature, geography, and other reference data is for informational purposes only. This information should not be considered complete, up to date, and is not intended to be used in place of a visit, consultation, or advice of a legal, medical, or any other professional.