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Interference Problems of Fluorescent Lamps Operating on High Frequency Electronic Ballasts with Infrared Remote Control Equipment and Infrared Simultaneous Interpretation System

From https://assistivelisteningknowledgebase.org/evidence/emsd-2003-infrared-interference/ · record checked 9 October 2026

  • Wu M (Martin Wu Kwok-tin)
  • Energy Efficiency Office, Electrical and Mechanical Services Department, Hong Kong SAR Government

Government (Electrical and Mechanical Services Department, Hong Kong SAR Government; written by a department engineer)

Summary

A Hong Kong government engineer's paper on how sunlight, incandescent lamps and fluorescent lamps on high-frequency electronic ballasts interfere with infrared remote controls and infrared interpretation systems, and how to avoid it.

Key findings

  • Reproduces an IEC subcarrier allocation for infrared consumer products: remote controls up to 40 kHz, conference systems 40 kHz-1 MHz, high-speed remote control and data 1-2 MHz, high-fidelity audio 2-6 MHz and analogue video 6-30 MHz.
  • Explains that direct sunlight on an infrared receiver saturates its photodetector and generates considerable noise, so venues with large windows need screening or additional radiators.
  • Says tungsten and halogen lamps, dimmed or not, emit enough infrared to add considerable noise, may need extra radiators, and should not be used in conference rooms with infrared interpretation systems.
  • Reports that fluorescent lamps on fixed electronic ballasts at about 40 kHz can interfere up to about 280 kHz (the 7th harmonic), and on dimmable ballasts running at 40-100 kHz up to about 400 kHz, so analogue systems on low subcarriers need precautions and, where information is lacking, a site test.
  • Describes infrared's inability to pass opaque structures such as walls and doors as giving privacy and no cross-talk between rooms, with typical systems carrying up to 16 channels.
  • Recommends digital infrared systems in the 3-6 MHz band, within the IEC's high-fidelity audio range, to avoid ballast interference, and early collaboration and a joint site test by the lighting and interpretation engineers.

Limits

Written in 2003 for simultaneous interpretation systems in Hong Kong conference rooms (40 kHz-1 MHz subcarriers), not for assistive listening receivers, and before LED lighting was common. It reports no measurements of its own and names one maker's digital system as an example.

Read the original

www.emsd.gov.hk/filemanager/en/content_764/infrared_interference_emsdweb.pdf

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Cited in

Cite this source

Wu M (Martin Wu Kwok-tin). Interference Problems of Fluorescent Lamps Operating on High Frequency Electronic Ballasts with Infrared Remote Control Equipment and Infrared Simultaneous Interpretation System. Energy Efficiency Office, Electrical and Mechanical Services Department, Hong Kong SAR Government. August 2003. https://www.emsd.gov.hk/filemanager/en/content_764/infrared_interference_emsdweb.pdf (accessed 9 October 2026).

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