X-RAY-EMISSION FROM BROADCAST TRANSMITTERS

During the past few years, amplitude-modulated transmitters employing efficient pulse-width modulators have come into common use. These transmitters are reliable, relatively insensitive to vacuum tube characteristics, and offer excellent audio fidelity; however, their architecture requires supply voltages in the 20 to 30 kilovolt range which greatly enhances th e production of ionizing radiation in the form of x-rays. Recent analysis by Voice of America indicates that these x-rays are being emitted in short, high-intensity bursts focused into broad radial beams. Part I of this paper reviews the general aspects of ionizing radiation of interest to communications engineers. Part II examines the spectral and time domain characteristics of x-ray radiation from transmitters, suggests a method for estimating fault condition radiation values, and discusses the findings of the Voice of America. © 1990 IEEE