International Special Committee Research Articles

CISPR Subcommittee A uncertainty activity [RFI measurement

Measurement uncertainty in making electromagnetic compatibility (EMC) measurements is a concern for test laboratories as well as their customers when products are assessed for compliance with limits. The ground-breaking work of the International Special Committee on Radio Interference (CISPR) on measurement uncertainty over the past decade is presented up to and including the latest national comments and voting documents on the topic.

Compliance Conducted EMI Analysis—A Case Study

The compliance conducted EMI measurement analysis primarily depends on the selection of specific impulsive bandwidth to measure emissions in the frequency range of interest. Such bandwidths are specified in International special committee on radio interference (CISPR) specification no. 16–1. The other factors which can influence conducted EMI measurement analysis are video bandwidth (VBW), sweep time (ST), amplitude mode selection (linear or logarithmic) & RF input attenuation of EMI receiver. This paper deals with measurement analysis of conducted EMI, where peak emissions exceed average regulatory limits but remain below quasi-peak limits. In such case, average measurement analysis is recommended. Subject analysis can be carried out either in automated or manual mode. But there are some older versions of EMI receiver, which measures average conducted EMI in manual mode only. Such average measurement analysis is employed by video filtering technique. This paper intends to find out influence of various parameters on conducted EMI manual average measurement analysis.

Flight Experience with the Novacor LVAS

As Novacor LVAS recipients continue to be discharged from the hospital to await cardiac transplantation, an increasing number of patients either need or desire to use air transportation. To date, two test experiences have been reported with the Novacor LVAS operating in a mock circulatory loop during air travel. One involved the transport of a mock loop on a medical helicopter, and another preceded an international flight of an LVAS recipient from Japan to the United States. In each situation, the LVAS, connected to a water-filled mock circulatory loop, was placed on the aircraft and instrumentation was checked to verify that there was no adverse effect on the Novacor equipment, or on aircraft systems, during flight. Novacor LVAS recipients have also been reported to have flown more than 37 commercial air transports throughout Europe, in both rotary and fixed wing aircraft, without incident. Laboratory testing of electromagnetic emissions were also conducted to include specific frequencies utilized by aircraft instrumentation. These tests show that the Novacor LVAS is well below the International Special Committee on Radio Interference (CISPR 11) emissions limits; these data can be provided to an air carrier anticipating transport of a Novacor recipient. Details of the results from the mock loop field testing, as well as the laboratory testing of electromagnetic emissions pertinent to air travel, are presented. This experience suggests that that there has been no impact on aircraft electronics from the LVAS, nor has the aircraft instrumentation generated any interference with the components of the Novacor LVAS.

FLIGHT EXPERIENCE WITH THE NOVACOR LVAS

As Novacor LVAS recipients continue to be discharged from the hospital to await cardiac transplantation, there has been an increasing number of patients that either need or desire to use air transportation. To date, two test flight experiences have been reported with the Novacor LVAS operating in a mock circulatory loop during air travel. One situation was the transport of a mock loop on a medical helicopter, and another one preceded an international flight of an LVAS recipient from Japan to the United States. In each situation, the LVAS, connected to a water-filled mock circulatory loop, was placed on the aircraft and instrumentation was checked to verify that there was no adverse effect on the Novacor equipment during flight. Novacor LVAS recipients have also been reported to have flown commercial air transports throughout Europe, in both rotary and fixed wing aircraft, without incident. Laboratory testing of electromagnetic emissions were also conducted to include specific frequencies utilized by aircraft instrumentation. These tests show that the Novacor LVAS is well below the International Special Committee on Radio Interference (CISPR 11) emissions limits; this data can be provided to an air carrier anticipating transport of a Novacor recipient. Details of the results from the mock loop field testing, as well as the laboratory testing of electromagnetic emissions pertinent to air travel, will be presented. This experience suggests that that there has been no impact on aircraft electronics from the LVAS, nor has the aircraft instrumentation generated any interference with the components of the Novacor LVAS.

The early history of radio interference

The need for control of interference to broadcast reception together with the realization that differing controls could constitute trade barriers led to the establishment in 1934 of the CISPR (International Special Committee on Radio Interference). Agreement on basic measuring techniques, instrumentation design and suppression methods was achieved quite rapidly. Agreement on actual limits took longer.

Protection of radiocommunications against interference from ISM equipment

Major problems of the protection of radiocommunication services against interference due to incidental radiation from industrial, scientific, and medical (ISM)equipment are considered. A theoretical model is proposed to explain the role of various factors involved. The model allows for estimation of the fraction of the transmitter coverage area lost due to unacceptable interference. Various theoretical possibilities and strategies of protection against the interference are discussed, and practical difficulties are outlined. The status of international recommendations made by theIUT(International Union of Telecommunications) andCISPR(International Special Committee on Radio Interference) in this field is presented.

Progress in the Work of CISPR

This review paper on the Comité International Spécial des Perturbations Radioélectriques (International Special Committee on Radio Interference) presents objectives ("to promote international agreement on many aspects of radio interference . . ."), member organizations, and structure. There are three subcommittees (on limits, on methods of measurement, and on safety) which meet in plenary assembly every three years. Inputs to these subcommittees are furnished by ten working groups that meet, usually yearly, to discuss specific study questions which may lead to a report. In many cases they lead to recommendations; member national committees of the International Electrotechnical Committee then may ask their governments to approve pertinent legislation.

The World Power Conference

WE have received from the Central Office of the World Power Conference, Kingsway, London, the annual report for 1937. Dr. William F. Durand is the president and Sir Harold Hartley is the chairman of the International Executive Council. The first conference was held in London in 1924, the second in Berlin in 1930 and the third in Washington in 1936. In addition, six other special meetings have been held. The next meeting of the council will take place in Vienna on August 29, 1938. The total number of National Committees of the World Power Conference is now 42, and in addition there are four member-countries with representatives. After the conference at Vienna this year there will be a study-tour of about a week's duration. The Central Office continues to circulate to the National Committees and representatives, reports on the work being carried on by the International Special Committee on Radio Interference, under the auspices of the International Electrotechnical Commission.