نتایج جستجو برای: pulse doppler
تعداد نتایج: 134303 فیلتر نتایج به سال:
Aortic stiffness is an independent predictor factor for cardiovascular risk. Different methods for determining pulse wave velocity (PWV) are used, among which the most common are mechanical methods such as SphygmoCor or Complior, which require specific devices and are limited by technical difficulty in obtaining measurements. Doppler guided by 2D ultrasound is a good alternative to these method...
BACKGROUND AND OBJECTIVE During off-pump coronary bypass grafting, surgical manipulation and dislocation of the heart may cause cardiovascular instability. Monitoring of cardiac output facilitates intraoperative haemodynamic management but pulmonary artery catheters are often considered too invasive. Pulse contour analysis and transoesophageal echocardiography could serve as alternatives, but t...
Introduction: Coronary artery disease secondary to atherosclerosis is the most common cause of mortality. Coronary angiography is the most precise method for determining the extent of disease in the coronary vascular bed. Arterial stiffness has been proposed as a marker of atherosclerosis in some studies. One of the noninvasive methods for the determination of arterial stiffness is Doppler echo...
Range and velocity estimation of moving targets using conventional steppedfrequencypulse radar may suffer from the range-Doppler coupling and the phasewrapping. To overcome these problems, this paper presents a new radar waveform namedmultiple stepped-frequency pulse trains and proposes a new algorithm. It is shown that byusing multiple stepped-frequency pulse trains and the robust phase unwrap...
There is a basic constraint imposed on radar measurements when the transmitted signal is a simple, CW pulse. As a result, the radardesigner may wish to use a more complex signal and thereby extract more information from an echoing object. Unfortunately, the processed returns of the sophisticated waveforms usually consist of a peak response and small adjacent responses (called "time sidelobes") ...
Within the last decade the quantification of pulse wave reflections mainly focused on measures of central aortic systolic pressure and its augmentation through reflections based on pulse wave analysis (PWA). A complementary approach is the wave separation analysis (WSA), which quantifies the total amount of arterial wave reflection considering both aortic pulse and flow waves. The aim of this w...
A Doppler radar emulator was developed to simulate the expected mean returns from scanning radar, including pulse-to-pulse variability associated with changes in viewing angle and atmospheric structure. Based on the user’s configuration, the emulator samples the numerical simulation output to produce simulated returned power, equivalent radar reflectivity, Doppler velocity, and Doppler spectrum...
An approach to predict real-time & Matlab Simulation Technique for realisation of speed, classification, ranging of different moving and static target in hostile environment using MIMO Radar.LMS & NLMS Algorithms, TCF are used for unwanted noise & clutter elimination technique using Matlab Programming. In this context authors are try to make an automated system that adjust target’s dynamic char...
In this paper, the application of vector analysis tool in the illuminated area and the Doppler frequency distribution research for the airborne pulse radar is studied. An important feature of vector analysis is that it can closely combine the geometric ideas with algebraic calculations. Through coordinate transform, the relationship between the frame of radar antenna and the ground, under aircr...
Superiority of poly-alphabetic sequences (PAS) for pulse compression radar over the binary and ternary sequences was established earlier. However, the enlarged alphabets in poly–alphabetic sequences deteriorate the noise and Doppler robustness at higher lengths in high resolution radar (HRR) systems. In this paper, poly-semantic sequences (PSS) with restricted alphabet {+1,-1} are considered an...
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