This document describes several aspects relating to the design of dc-dc converters operating at frequencies in the VHF range (30-300 MHz). Design considerations are treated in the context of a dc-dc converter operating at a switching frequency of 100 MHz. Gate drive, rectifier and control designs are explored in detail, and experimental measurements of the complete converter are presented that ...

Viral haemorrhagic fevers (VHF) comprise a group of at least 13 diseases caused by viral infections which may produce severe haemorrhagic complications. VHF are distributed throughout much of the tropics and subtropics. The aetiological agents belong to various families of viruses and can be classified epidemiologically into 4 groups according to their modes Of transmission [5]. VHF are geograp...

The paper presents an analysis of scientific and practical development software-configurable radio monitoring module based on RTL2832U tuner in Simulink environment order to scan a given ultra-short-wave (VHF) frequency range perform automatic search, counting output the number broadcasting stations. Given is structural circuit diagram modernized SDR-receiver (Software Defined Radio) with inclu...

Airborne synthetic aperture radar (SAR) operating in the VHF band and used in conjunction with change detection has shown promising results for wide-area surveillance of ground targets. By using VHF-band frequencies, both targets in the open as well as concealed by foliage may be detected in a robust manner. VHF-band SAR is able to detect hidden targets because both foliage attenuation and clut...

Using the MU radar at Shigaraki, Japan (34.85°N, 136.10°E), we measure the power distribution pattern of VHF radar echoes from the mid-troposphere. The large number of radar beam-pointing directions (320) allows the mapping of echo power from 0° to 40° from zenith, and also the dependence on azimuth, which has not been achieved before at VHF wavelengths. The results show how vertical shear of t...

INTRODUCTION There have been 3 outbreaks of viral hemorrhagic fever (VHF) in Uganda in the last 2 years. VHF often starts with non-specific symptoms prior to the onset of haemorrhagic signs. HIV clinics in VHF outbreak countries such as Uganda see large numbers of patients with HIV 1/2 infection presenting with non-specific symptoms every day. Whilst there are good screening tools for general h...

Text-dependent speaker verification over degraded radio channel is a challenging task. To better understand the research problem, the Institute for Infocomm Research (I2R) of Singapore has collected a corpus of voice recordings transmitted over marine VHF. Built as an extension of the RSR2015 database, the VHF-RSR2015 consists of recordings from 300 speakers of Part I of the RSR2015 database tr...

PURPOSE To assess the effectiveness of a keratoconus-detection algorithm derived from Artemis very high-frequency (VHF) digital ultrasound (ArcScan Inc., Morrison, CO) epithelial thickness maps in the fellow eye from a series of patients with unilateral keratoconus. METHODS The study included 10 patients with moderate to advanced keratoconus in one eye but a clinically and algorithmically top...