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Automatic audio signal detector for telephone voice lines - has resonant and broadband amplifiers which are coupled to voice lines
Automatic audio signal detector for telephone voice lines - has resonant and broadband amplifiers which are coupled to voice lines
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机译:用于电话语音线路的自动音频信号检测器-具有耦合到语音线路的谐振和宽带放大器
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摘要
The automatic audio signal detector, for the voice lines in a telephone system has a resonant amplifier and there is a broadband amplifier which is connected to the voice lines of a calling subscriber circuit. Each amplifier is associated with a relay which is used to control the monitoring of the audio signal timing relay chain and a time switch. The advantage lies in the detector recognising an audio signal amidst noise arising e.g. from the presence of unwanted tones during selection, and the apparatus detects the signal despite obstructions e.g. engage tone in pre-selection stage.
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