ELECTROACOUSTIC SPEECH INTELLIGIBILITY ENHANCEMENT METHOD AND APPARATUS

摘要

One or more electronically-controllable blocks rapidly vary the device's acoustic gain. The electronically-controllable blocks variably amplify or attenuate the incoming signal, controlled by the output signals of one or more level detectors. The input signals of the level detectors are representative of the acoustic input signal being processed by the apparatus and produce controlling signals in response to detection of sound pressure levels within a predetermined range. Multi-level compression is achieved when a first level detector in conjunction with an electronically-controllable amplifier block compresses signals which have an input sound pressure level above a compressor lower bound α and below a compressor upper bound β, and when a second level detector in conjunction with either an electronically-controllable amplifier or attenuator block compresses signals which have a sound pressure level above a second compressor lower bound η. For input signals of sound pressure level below α or between β and η, amplification is linear. Input amplifier saturation is prevented by having the second level detector alter the transmission of an electronically-controlled attenuator placed prior to the first stage of amplification. Single-level compression is provided by independent detection and utilization of compression ranges α to β and over η.