Results 11 to 20 of about 121,274 (339)

All-Optical Pulsed Signal Doppler Frequency Shift Measurement System

open access: yesIEEE Photonics Journal, 2021
A simple and all-optical Doppler frequency shift (DFS) measurement system is presented. It is based on a dual-drive Mach Zehnder modulator (DDMZM) driven by a transmitted signal and an echo signal received by an antenna.
Chongjia Huang, Erwin H. W. Chan
doaj   +1 more source

Acquisition of Time and Doppler Shift in WFRFT Encrypted Chaotic Direct Sequence Spread Spectrum System

open access: yesIEEE Access, 2022
Weighted fractional Fourier transform encrypted chaotic direct sequence spread spectrum (WFRFT-CD3S) signal is aperiodic and complex Gaussian distributed.
Jiangyan He   +3 more
doaj   +1 more source

A Doppler Shift Factor Estimation Method for High Speed Mobile Underwater Acoustic Communication [PDF]

open access: yesJisuanji gongcheng, 2016
In underwater acoustic communication systems,most of the Doppler shift factor estimation methods cannot deal with the relationship between computational complexity and estimation accuracy under high relative motion speed.In view of this,this paper ...
YANG Jie,ZHOU Shengyuan,YU Fengqi
doaj   +1 more source

Micro-Doppler Parameters Extraction of Precession Cone-Shaped Targets Based on Rotating Antenna

open access: yesRemote Sensing, 2022
Micro-Doppler is regarded as a unique signature of a target with micro-motions. The sophisticated recognition of the cone-shaped targets can be realized through the micro-Doppler effect.
Zhihao Wang   +4 more
doaj   +1 more source

Normal Doppler Frequency Shift in Negative Refractive‐Index Systems [PDF]

open access: yesLaser & Photonics Reviews, 2019
AbstractBesides the well‐known negative refraction, a negative refractive‐index material can exhibit another two hallmark features, which are the inverse Doppler effect and backward Cherenkov radiation. The former is known as the motion‐induced frequency shift that is contrary to the normal Doppler effect, and the latter refers to the Cherenkov ...
Xiao Lin, Baile Zhang
openaire   +3 more sources

Multi-frequency observations of E-region HF radar aurora [PDF]

open access: yesAnnales Geophysicae, 2003
Multi-frequency observations of E-region coherent backscatter from decametre waves reveal that auroral echoes tend to comprise two spectral components superimposed, one at low Doppler shifts, below 250 ms-1, and the other Doppler shifted to near ...
S. E. Milan, M. Lester, N. Sato
doaj   +1 more source

Micro-Motion Parameter Extraction of Multi-Scattering-Point Target Based on Vortex Electromagnetic Wave Radar

open access: yesRemote Sensing, 2022
In addition to traditional linear Doppler shift, the angular Doppler shift in vortex electromagnetic wave (VEMW) radar systems carrying orbital angular momentum (OAM) can provide more accurate target identification micro-motion parameters, especially the
Lijun Bu   +5 more
doaj   +1 more source

Spectral and temporal gating mechanisms enhance the clutter rejection in the echolocating bat, Rhinolophus rouxi [PDF]

open access: yes, 1991
Doppler shift compensation behaviour in horseshoe bats, Rhinolophus rouxi, was used to test the interference of pure tones and narrow band noise with compensation performance.
Neumann, Ingrid, Schuller, Gerd
core   +1 more source

Storage of Doppler-Shift Information in the Echolocation System of the "CF-FM"-Bat, Rhinolophus ferrumequinum [PDF]

open access: yes, 1976
The greater horseshoe bat (Rhinolophus ferrumequinum) emits echolocation sounds consisting of a long constant-frequency (CF) component preceeded and followed by a short frequency-modulated (FM) component. When an echo returns with an upward Doppler-shift,
Schuller, Gerd, Suga, Nobuo
core   +1 more source

Hearing Characteristics and Doppler Shift Compensation in South Indian CF-FM Bats [PDF]

open access: yes, 1980
1. Echolocation pulses, Doppler shift compensation behaviour under laboratory conditions and frequency response characteristics of hearing were recorded inRhinolophus rouxi, Hipposideros speoris andHipposideros bicolor. 2.
A. Brosset   +13 more
core   +1 more source

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