Patent
Voice detector circuit
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TLDR
In this article, a slew-rate limited amplifier is used to reduce the interference with the voice detection process caused by impulse noise, and a logarithmic amplifier is included for the purpose of optimizing the separation of the syllabic-rate envelope from the audio signal.Abstract:
A voice detector circuit including a slew-rate limited amplifier at the input thereof so as to reduce the interference with the voice detection process caused by impulse noise. The slew-rate limited amplifier is essentially transparent to audio signals, while providing severe attenuation of impulse noise components. The actual determination of the voice content of the audio signal is provided by comparing the average syllabic-rate content of the impulse noise limited, audio signal with the peak noise content thereof. Additionally, a logarithmic amplifier is included for the purpose of optimizing the separation of the syllabic-rate envelope from the audio signal.read more
Citations
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Vehicular sound-processing system incorporating an interior mirror user-interaction site for a restricted-range wireless communication system
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References
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Patent
Audio signal quality indicating circuit
TL;DR: In this article, a system for selecting one of a plurality of signal transmission paths, a circuit is provided for each path to indicate the quality of an audio signal delivered by the path, consisting of a log amplifier, an envelope detector and indicating means including a signal detector, a noise detector and a difference amplifier.
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TL;DR: In this paper, a method and circuit for detecting transient noise pulses having predetermined characteristics which are contained in an input signal, and substituting for the portion of the input signal distorted by the noise pulse, an estimate of that portion based upon portions of the inputs outside the distorted portion.
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TL;DR: In this paper, a radio receiver squelch circuit is proposed to amplify and pass signals when the audio component exceeds the noise component by a predetermined ratio and to shunt the signals, thus squelching any output.
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Audio frequency squelch system
TL;DR: The audio frequency squelch system as discussed by the authors selects signals in the upper and lower portions of the voice frequency range and processes these signals separately, with variations in the duty cycle of the output pulses which occur at a voice syllabic rate (under 325 hertz) being selected.