| 摘要 |
A circuit for conditioning an input signal containing audio and noise components is provided in which a first circuit branch is used for deriving a first DC signal proportionate to the decibel level of high band information in the input signal and a second circuit branch is used for deriving a second DC signal proportionate to the amplitude of the input signal. A preselected maximum threshold reference is provided when the second DC signal drops below a preselected threshold and also for a predetermined time period when the second DC signal rises above the preselected threshold. The first DC signal and the maximum threshold reference are used to provide a peak detector signal input which is maintained at a level equal to the most negative level of the first DC signal when the maximum threshold reference is not provided and at a level equal to the most positive level of the first DC signal but not greater than the preselected maximum threshold reference when the maximum threshold reference is provided.
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