نتایج جستجو برای: pulse doppler
تعداد نتایج: 134303 فیلتر نتایج به سال:
The superiority of multiple-input multiple-output (MIMO) radars over conventional radars has been recently shown in many aspects. These radars consist of many transmitters and receivers located far from each other. In this scenario, the MIMO radar is able to observe the targets from different directions. One of the advantages of these radars is exploitation of Doppler frequencies from different...
Objective: This prospective study was undertaken to assess the sensitivity and specificity of color flow mapping and pulse Doppler waveform in identifying malignancy preoperatively in adnexal masses in perimenopausal women. Materials and methods: A total of 100 cases with adnexal masses in perimenopausal women were scanned, underwent color flow mapping and pulsed Doppler waveform studies. These...
Small vibrations are simultaneously measured at two adjacent points on the aortic wall near the aortic valve by electronically alternating the directions of the ultrasonic beam. The transit delay time of the pulse wave between these two points is determined from two vibration signals obtained by this alternation beam method. The local pulse wave velocity at several millimeters on the aorta is p...
Abstract Specifying parameters of high‐speed targets as range and velocity in radar systems operating with phase‐modulated signals is a problematic process because the serious effect high Doppler frequency on these types waveforms. In existence target, its will be very such that it totally changes phase sequence received signal. As result, matched filter output distorted. Therefore, estimating ...
This numerical study demonstrates that Doppler redshift exists in the reflected spectrum of a few-cycle pulse, propagating through a dense medium. It manifests itself in two different forms, a sharp low-frequency spike (LFS) located at the red edge of the reflected spectrum and a relatively broader redshift near the carrier frequency. With the variation of the laser and medium parameters, the d...
X-ray brightness oscillations with frequencies from 300 600 Hz have been observed in six low mass X-ray binary (LMXB) bursters with the Rossi X-ray Timing Explorer (RXTE). These oscillations likely result from spin modulation of a hot region on the stellar surface produced by thermonuclear burning. If this hypothesis is correct the rotational velocity of the stellar surface, ≈ 0.1 c, will intro...
The s-transform is a variable window of STFT and extension of wavelet. This paper discussed the principle and method of Wavelet De-noising, reduced noise of pulse signal based on wavelet. It is shown that wavelet de-noising can eliminate most noise, and preserve effectively sudden change of signal. This paper analyzed and compared the effect of denoising of pulse signal in different ways all st...
1872-9312/$e seefrontmattera2008A doi:10.1016/j.artres.2008.11.002 Summary Measurement of pulse wave velocity is of increasing importance for assessment of arterial stiffness and risk evaluation. Different techniques are available, based either on pressure, distension or Doppler waveforms. Techniques not only differ by the algorithm used to identify specific part of the pulse signal, but also i...
We introduce a computationally efficient FFT-based algorithm for the design of OFDM/ OQAM pulse shaping filters of arbitrary length and with arbitrary overlapping factors. The basic idea of our approach is to start from an arbitrary initial (nonorthogonal) filter and to perform an orthogonalization which yields an ISIand ICI-free pulse shaping filter. The orthogonalization is performed in the d...
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