The incidence of radio-frequency impulsive noise within hospital buildings: initial measurements in the 450 MHz band
✍ Scribed by A.I Riemann; N.E Evans
- Publisher
- Elsevier Science
- Year
- 1999
- Tongue
- English
- Weight
- 356 KB
- Volume
- 21
- Category
- Article
- ISSN
- 1350-4533
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✦ Synopsis
This paper reports on the incidence and level of man-made electrical impulse noise capable of causing interference to low-power, ASK and FSK radio biotelemetry links. Measurements were made at two acute hospitals, one in a residential area of Belfast, Northern Ireland and the other in an industrial part of Berlin, Germany. Monitoring was effected in the 450 MHz band using a communications receiver with its AGC line disabled and AM-detector AM output fed to a PC-based logger. The RF bandwidth was 20 kHz and a rotatable folded-dipole receiving antenna was used. Seven-day impulse counts were recorded at each location, for separate RF input thresholds of Ϫ100, Ϫ110 and Ϫ120 dBm and a common trigger window of 10 µs-10 ms. Histograms depicting the average pulse count per minute are presented; values range from a maximum of 55×10 3 /min for Ϫ120 dBm sensitivity in Berlin, to a minimum of 1.2/min for Ϫ100 dBm sensitivity in Belfast, both with vertical polarisation.