Effect of Pumping Pulse Duration on Echo Signal Amplitude in Four-Pulse PELDOR

An ultrasonic non-destructive testing has found out a new phenomenon in several stamped forgings made from heat-resistant nickel alloys (Ni-superalloys) of two grades: local attenuation of the bottom echo signal amplitude, when the workpiece surface had large (over 20 mm) randomly located zones with significant (up to 1.5%) fluctuations of the longitudinal ultrasonic wave propagation velocity. On top of that, there were no various grain sizes or coarse-grained structures that usually lead to a an increase of a rate of ultrasonic attenuation in such alloys, and which triggers off a bottom echo signal amplitude attenuation. The Article states the studies carried out to explain the tangible reasons of the detected macroinhomogeneity of the velocity, and how it associated with a bottom signal amplitude attenuation.

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Amplitude error correction in matrix simulators of radar targets

Radio Industry (Russia) ◽

10.21778/2413-9599-2020-30-4-106-110 ◽

2020 ◽

Vol 30 (4) ◽

pp. 106-110

Author(s):

T. I. Sabitov ◽

A. V. Kiselev

Keyword(s):

Radiation Pattern ◽

Target Position ◽

Signal Amplitude ◽

Echo Signal ◽

The Real ◽

Amplitude Error ◽

The Matrix ◽

Radar Targets ◽

Practical Implications ◽

Matrix Base

Problem statement. The compensation problem of the amplitude error occurring when modeling radar targets using matrix simulators is considered. The relations that reveal the concept of this error are given. The example shows that the amplitude of the simulated echo signal differs from the amplitude of the real one.Objective. Justification of a method for correcting the amplitude error observed when simulating echo signals from radar targets using emitter matrices.Results. It is shown that when the scanning radiation pattern is oriented normal to the matrix base, the amplitude of the simulated echo signal does not depend on the angular target position. Based on this, a method was proposed to eliminate the error through pre-distortion of the echo signal amplitude. The ratio for calculating the predistortion multiplier coefficient is obtained. In the framework of a numerical experiment, the amplitude of the simulated echo signal was estimated for various angular positions of the scanning radiation pattern without taking into account predistortion and with predistortion. The experimental results confirmed the correction effectiveness.Practical implications. The results obtained allow increasing the adequacy of modeling radar objects by matrix simulators by ensuring that the amplitude of the simulated echo signal corresponds to the amplitude of the real one.

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Feature Extraction of Underwater Target Ultrasonic Echo Based on Wavelet Transform

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.599-601.1517 ◽

2014 ◽

Vol 599-601 ◽

pp. 1517-1522 ◽

Cited By ~ 1

Author(s):

Zheng Long Wu ◽

Jie Li ◽

Zhen Yu Guan

Keyword(s):

Feature Extraction ◽

Wavelet Transform ◽

Signal Amplitude ◽

Main Task ◽

Echo Signal ◽

Denoising Method ◽

Ultrasonic Echo ◽

Envelope Extraction ◽

Underwater Target ◽

Breaking Points

Ultrasonic detection has been widely used in underwater detectoscopes as an important method for underwater detection. Feature extraction of echo signal time-delay and amplitude is the main task of processing underwater ultrasonic signal. Underwater target ultrasonic echo signal is influenced by reverberation and noise from the sea and system itself, reverberation interference of signal background is the main difficulty for target echo detection. So we use denoising algorithm to denoise echo signal. At first this paper denoises the measured weighted background clutter data using wavelet threshold denoising method, then the paper extracts breaking points of echo signal through wavelet transform, at last the paper makes an envelope extraction using Hilbert transform combined with wavelet transform methods, and acquires the feature information of echo signal amplitude.

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The Effects of Variable-Interval and Fixed-Interval Signal Presentation Schedules on the Auditory Evoked Response

Journal of Speech and Hearing Research ◽

10.1044/jshr.1201.199 ◽

1969 ◽

Vol 12 (1) ◽

pp. 199-209 ◽

Cited By ~ 12

Author(s):

David A. Nelson ◽

Frank M. Lassman ◽

Richard L. Hoel

Keyword(s):

Variable Interval ◽

Tone Burst ◽

Signal Amplitude ◽

Fixed Interval ◽

Interval Schedule ◽

Sensation Level ◽

Fixed Interval Schedule ◽

Auditory Evoked Responses ◽

Auditory Evoked Response ◽

Signal Presentation

Averaged auditory evoked responses to 1000-Hz 20-msec tone bursts were obtained from normal-hearing adults under two different intersignal interval schedules: (1) a fixed-interval schedule with 2-sec intersignal intervals, and (2) a variable-interval schedule of intersignal intervals ranging randomly from 1.0 sec to 4.5 sec with a mean of 2 sec. Peak-to-peak amplitudes (N 1 — P 2 ) as well as latencies of components P 1 , N 1 , P 2 , and N 2 were compared under the two different conditions of intersignal interval. No consistent or significant differences between variable- and fixed-interval schedules were found in the averaged responses to signals of either 20 dB SL or 50 dB SL. Neither were there significant schedule differences when 35 or 70 epochs were averaged per response. There were, however, significant effects due to signal amplitude and to the number of epochs averaged per response. Response amplitude increased and response latency decreased with sensation level of the tone burst.

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