Noise Gate Amplifiers
A Noise Gate is used to control the volume of an audio signal, attenuating signals which register below the threshold. They are comparable to a compressor, which attenuates signals above a threshold.
Used in recording studios and sound reinforcement. Musicians use small portable units to control unwanted noise from their amplification systems.
Band-limited noise gates are also used to eliminate background noise from audio recordings by eliminating frequency bands that contain only static.