Development of APD measuring equipment and its faculty

Amplitude probability distribution (APD) measuring equipment has been developed that can measure amplitude distribution semi-continuously. Two sets of this equipment at resolution bandwidths of 100 MHz and 1 MHz were used to make simultaneous APD measurements of electromagnetic disturbance leaking from a microwave oven. On comparing the results of both measurements, it was found that measurements made at a resolution bandwidth of 100 MHz were superior in terms of repeatability. In addition, simultaneous measurements were performed by the weighting method proposed by CISPR (at a video bandwidth of 10 Hz) and by APD measurements at a video bandwidth of 3 MHz. Based on the average value obtained from the latter measurements, a method is proposed to evaluate such leaking disturbance, and this method is compared with the results of the former measurements.