Measurement and estimation of BER degradation of PHS due to electromagnetic disturbances from microwave ovens

Abstract

Microwave ovens operating in 2.45 GHz band emit broad band noise that may interfere with digital mobile communication systems above 1 GHz. We therefore measured the bit error rate (BER) degradation of a typical personal handy-phone system (PHS) receiver due to the electromagnetic disturbances emitted from two types of ovens, five measurements in all, located 0.5, 1, and 3 m from the receiver. BER degradation over 10−3 was not observed from conventional transformer-type microwave ovens even at 0.5 m. Switching type ovens, such as are mainly used in Japan, generally radiate higher level disturbances than conventional ovens and an oven of this kind degraded the BER characteristics by more than 10−2 at 3 m. A noise waveform analyzer was developed to measure statistical parameters of the noise envelope such as the amplitude probability distribution (APD) and crossing rate distribution. APD of the noise envelope emitted from ovens was measured in the 1.9 GHz frequency band which is assigned for PHS. BER degradation of a PHS receiver by the disturbance of the ovens was also measured simultaneously with the APD measurement. Good correlation is found between BER and APD measurement results. An estimation method for BER from the APD measurement data is proposed and its applicability evaluated. © 1998 Scripta Technica. Electron Comm Jpn Pt 1, 81(2): 55–63, 1998