The present study investigated consistency of the constant frequency (CF) portion of biosonar pulse s emitted by CF-FM bats and relationship between the pulse emission and wing motion. Here, pulse CF2 frequency at rest, closely related to the reference frequency, was measured for several months. Besides, Doppler-shift compensation was investigated on different days by a telemetry-microphone (Te...

Pulse Compression Techniques are used in Radar systems to avail the benefits of large range detection capability of long duration pulse and high range resolution capability of short duration pulse with low power consumption. In this paper, details of these techniques are given which achieves high range resolution and low peak sidelobe levels under various noise conditions, Doppler shift and mul...

OBJECTIVE To illustrate the possible role of cerebral oximetry and stroke distance as measured by Doppler ultrasound in monitoring the critically ill patient non-invasively in the emergency department. METHODS Five critically ill patients were monitored with either cerebral oximetry or both cerebral oximetry and stroke distance (the distance travelled by blood in the aorta with each ventricul...

Kathryn Vowden, Peter Vowden Doppler ultrasound is frequently used as a screening tool when assessing patients for arterial disease. The use of Doppler ultrasound to calculate the ankle brachial pressure index (ABPI) has been tested for reliability and reproducibility and has been found to be an accurate technique when used regularly by appropriately trained practitioners. An alternative to Dop...

We discuss range and Doppler processing for FMCW radar using only a single pulse or frequency sweep. The first step is correlation processing, for which the range and Doppler resolution are limited by the ambiguity function. We show that this resolution can be optimized with an additional inverse filtering step. The method is demonstrated for sinusoidal FMCW radar measurements. Several regulari...

Abstract For pulse compression characteristics and not easily affected by noise, linear frequency modulation signal are widely used in underwater acoustic communication. This paper analyzes the characteristics of hyperbolic frequency modulation signal over underwater acoustic channels. Compared with linear frequency modulation signal, hyperbolic frequency modulation has the same performance of ...

As a result of an analysis of the autocovariance of the complex heterodyne lidar signal, some general-enough inverse techniques (algorithms) are derived for recovering with high range resolution, below the sensing pulse length, of Doppler-velocity profiles in the atmosphere. Unlike our preceding works, it is assumed here that the laser pulses can have arbitrary fluctuating shape. The presence i...

Doppler weather radar suffer from well known limitations associated with the trade off between range and velocity aliasing. This is particularly severe as the radar wavelength decreases. There are a number of operational 5 cm wavelength Doppler radars around the world and for reasonable maximum ranges of about 150 km, the unambiguous velocity is only about 13 ms. Automated processing techniques...

PURPOSE The goal of this study was to evaluate the effect of vascular compliance, resistance, and pulse rate on the resistive index (RI) by using an electrical circuit model to simulate renal blood flow. METHODS In order to analyze the renal arterial Doppler waveform, we modeled the renal blood-flow circuit with an equivalent simple electrical circuit containing resistance, inductance, and ca...