A versatile multichannel biotelemetry system

A radiotelemetry system is introduced for analyzing several physiological parameters from free ranging patients within a transmission range of 100 metres. The parameters considered are two independent electromyograms, an electrocardiogram, and a body position indicator. A battery status signal is also transmitted. An equalizer network is utilized to improve the overall frequency response of the system. The composite signal from the equalizer can be recorded by using a tape recorder and demulitiplexed simultaneously. A filter bank is used for demultiplexing. Each filter unit in the bank provides outputs that emphasize and at the same time suppress signals in the same frequency range. The suppressed output supplies the signal to proceeding stages. Hence, an efficient filtering of closely packed multiplexed signals is achieved. The incoming original signals are recovered at outputs of demodulators following the filter bank. The proposed system provides an efficient and cost-effective way of physiological signal detection and storage from free-ranging patients. It is designed using commonly available electronic components. It can be implemented easily, and adapted to other physiological and physical parameters of interest.