Biotelemetry of EKG Signals Within a Small, Closed Chamber

Abstract

A requirement arose for reliably telemetering EKG data from personnel within a closed metallic chamber to a receiver also located within the chamber. Although there is much information in the literature on biomedical telemetry, it generally deals with propagation of telemetry signals in the clinical laboratory or the field; little, if any, pertains to the problem at hand. Analysis of the environment showed that mathematical prediction of the propagation characteristics of the chamber would be difficult, if not impossible, due to its odd interior configuration. An empirical approach was taken. Several system approaches were considered; an FM/AM system and an FM/FM system were built and each evaluated in the actual environment. Data are presented on test results. A successful system is discussed, including a description of the receiving antenna network employed to ensure reception of the transmitted signals regardless of the location of personnel within the chamber. Conclusions regarding the chamber characteristics are given.