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DAB interference from LED lighting: industry debates solutions


Representatives from international broadcasters have been discussing how to handle interference to digital radio from poor quality LED lighting.

A joint workshop between the International Telecommunications Union (ITU) and the EBU (European Broadcasting Union) focused on the risk of interference into the reception of the DAB system from non-radiocommunication devices, like light-emitting diode (LED) lighting systems and other apparatuses using switch-mode power supplies.

Participants discussed the results of measurements and tests in multiple countries as well as the role of administrations in limiting interference and information about ITU’s related activities.

Several countries in Europe have either decided or are considering switching over from analogue FM Radio to DAB. This is accompanied by an increased number of DAB receivers in use. At the same time, the use of LED lighting systems is massively growing – and there is an increasing number of low-cost, poorly designed gadgets, domestic appliances, multi-media equipment, personal computers, and tools using switch-mode power supplies. This has led to more cases of interference to DAB reception reported to administrations and broadcasters.

Two EBU member organizations – NRK from Norway and SRG-SSR from Switzerland – and one European Broadcast Network Operator, Arqiva from UK, presented their respective results of field investigations and measurements and explained their findings and analyses of the factors causing the interference cases.

It was noted that the problems experienced with LED lighting systems should be seen as more of an illustration of the deeper underlying problems involved. A common factor is the near universal use now of switch-mode techniques in power supplies and AC-to-DC and DC-to-DC power converters. These tend to produce high levels of radio-frequency (RF) energy, which appears as radiated emissions across wide ranges of frequency and leakage of RF energy onto electrical mains wiring. Increasing levels of RF energy on mains wiring then causes thermal stress and rapid ageing of filter components in other connected equipment, thus creating a vicious circle of degradation and increasing RF noise. These factors are particularly evident with LED lighting systems on account of their ubiquitous use these days.

Looking to the future, the delegates agreed that action was necessary to improve equipment design and standards to reflect the proliferation of electrical and electronic equipment and minimize levels of RF noise in the environment. This is essential for ensuring that the planning criteria for radiocommunication services and resulting service availability are not compromised by a rising noise floor.

Fran├žois Rancy, Director of ITU’s Radiocommunication Bureau said:
“This workshop has emphasized how important our collaboration with CISPR is in order to continue to fulfill ITU’s role in developing a sustainable ecosystem of radiocommunications throughout the world." 

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