PURPOSE The aim of this study was to investigate factors that influence arterial Doppler waveforms in an in vitro phantom to provide a more accurate and comprehensive explanation of the Doppler signal. METHODS A flow model was created using a pulsatile artificial heart, rubber or polyethylene tubes, a water tank, and a glass tube. Spectral Doppler tracings were obtained in multiple combinatio...

Digital Signal Processing techniques for ground surveillance RADAR has been thoroughly investigated and optimized for an improved detection of target. Using the established techniques like Pulse compression, Fast Fourier Transform and Windowing, the present work optimizes the selection of pulse coding techniques, window type and different filters.The work proposes techniques to mitigate inheren...

Pulse Doppler radars suffer from range-Doppler ambiguity that translates into a trade-off between maximal unambiguous range and velocity. Several techniques, like the multiple PRFs (MPRF) method, have been proposed to mitigate this problem. The drawback of MPRF method is received samples are not processed jointly, decreasing signal noise ratio (SNR). To overcome drawbacks MPRF, we employ random...

When a target has a large velocity, the Doppler effect is not negligible. In that case, pulse compression by means of a linear frequency modulation suffers from significant signal loss in performance due to the mismatch between the reflected signal and the matched filter caused by the Doppler distortion. This problem can be avoided by using a hyperbolic frequency-modulated waveform, which has t...

background and aims. although salivary gland tumors are not very common, early diagnosis and treatment is crucial because of their proximity to vital organs, and therefore, determining the efficacy of new imaging procedures becomes important. this study aimed to evaluate the efficacy of magnetic resonance imaging (mri) and color doppler ultrasonography parameters in the diagnosis and differenti...

Multiple input multiple output radars transmit partially coherent or noncoherent waveforms for improving spatial resolution or spatial diversity. While waveform design for SIMO radars concentrate on improving the delay and Doppler resolution characteristics, waveform design for MIMO radars involve optimization of delay, Doppler and spatial resolution characteristics. The resolution properties o...

BACKGROUND AND PURPOSE Thromboembolism in paroxysmal atrial fibrillation (AF) has often been attributed to occult AF. We hypothesized that the surface ECG may not always reflect left atrial appendage (LAA) mechanical function. METHODS Transesophageal echocardiographic images from 201 consecutive patients undergoing transesophageal echocardiography by a single operator were reviewed. LAA pulse...