FIR
Initialism of finite impulse response; that has impulse response (or response to any finite length input) of finite duration.
Adjective
- Initialism of finite impulse response; that has impulse response (or response to any finite length input) of finite duration.
Noun
- Initialism of flight information region; a specified region of airspace in which a flight information service (FIS) and an alerting service (ALRS) are provided.
- Initialism of first information report.
- Abbreviation of far infrared or far infrared radiation.