Study of Spectrum Analyzer Installed in Wireless Medical Telemetry Receiver

Abstract

The management of the electromagnetic environment is important for the safe operation of a wireless medical telemeter (WMT). The spectrum analyzer (SA) has been widely used in the investigation and evaluation of electromagnetic environments, including clinical settings. Recently, the simplified SA (SSA) is often installed in WMT receivers. We investigated the performance and usage note of the SSA. The indicated value of the received signal level was also correlated with that of an actual SA, but the measurement error of the signal level was higher than that of the actual SA. In addition, 420 MHz to 450 MHz electromagnetic noise due to the operation of the WMT radiated into the near field of the WMT receiver. Therefore, a separation distance between the WMT receiver and the receiving antenna is required. On the other hand, the SSA can proportionally measure the received signal level in the 420 to 450 MHz band by using one channel of 12.5 kHz. The SSA is potentially useful for basic electromagnetic environment investigations, such as the survey of the usage conditions of WMT channels and the inspection of out-coming radio waves or electromagnetic noise sources.