FM System
Pronunciation: EFF-em SIS-tem
Also written as: FM — Frequency Modulation System
An assistive listening device that wirelessly transmits a speaker's voice via radio frequency directly to a receiver worn by or coupled to the hearing aid of a listener, improving the signal-to-noise ratio in challenging listening environments.
Full Definition
An FM (Frequency Modulation) system consists of a transmitter—typically worn or held by a teacher or communication partner—and a receiver used by the person with hearing loss. The transmitter picks up the speaker's voice via a close-microphone and sends it via FM radio signal to the receiver, which delivers the signal directly to the listener's hearing aid or cochlear implant processor. This dramatically improves the effective signal-to-noise ratio by keeping the voice signal consistent regardless of the listener's distance from the speaker or background noise levels. FM systems are extensively used in educational settings. Editors should capitalise 'FM' and render 'FM system' in lowercase for the generic noun. It should not be confused with hearing loops, which use electromagnetic induction rather than radio transmission.
Usage
Usage note: Always capitalise 'FM.' The noun phrase is 'FM system' (lowercase 's'). On first mention, consider expanding to 'frequency modulation (FM) system' in formal clinical documents. Do not confuse with infrared or hearing loop technologies.
In Context
- "The educational audiologist recommended that the child use an FM system in the classroom to improve access to the teacher's speech." — Educational audiology support plan
- "The manufacturer's documentation consistently referred to the device as an 'FM system' rather than a 'personal microphone system,' and the editorial team preserved this terminology." — Medical device documentation editorial note