On-board hands-free communication apparatus
AssigneeDenso Corporation
InventorToshihiro Hosoi
Life of this patent
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Abstract
In an on-board hands-free communication apparatus, a gain of an amplifier of a speaker for outputting an incoming voice signal from a telephone device varies with a volume set value of a speaker volume switch adjusted by an user. When the gain of the amplifier increases equal to or greater than a threshold value, a feature extraction amplification circuit performs a feature extraction amplification processing to apparently amplify output power of the incoming voice signal, and a control circuit fixes the gain of the amplifier to the threshold value regardless of the volume set value.
Claims2
An on-board hands-free communication apparatus communicable with a telephone device, the hands-free communication apparatus comprising:
- a calculation circuit configured to perform an echo cancel calculation on outgoing and incoming voice signals to and from the telephone device to reduce an acoustic echo signal contained in the outgoing voice signal, the acoustic echo signal originating from a portion of the incoming voice signal that is outputted from a voice output device, picked up by an voice input device, and transmitted back to the telephone device;
- a volume control circuit having a volume set value adjustable to adjust a volume of the voice output device;
- an amplifier circuit coupled downstream of the voice output device and having a gain set value, the amplifier circuit being configured to linearly amplify output power of the incoming voice signal according to the gain set value when the gain set value is less than a predetermined gain threshold value, the amplifier circuit being configured to nonlinearly amplify the output power of the incoming voice signal according to the gain set value when the gain set value is equal to or greater than the gain threshold value;
- a control circuit configured to allow the gain set value of the amplifier circuit to vary with the volume set value of the volume control circuit;
- and
- a feature extraction amplifier circuit coupled between the telephone device and the amplifier circuit and configured to selectively perform a feature extraction amplification processing that extracts a feature component of the incoming voice signal and amplifies the extracted feature component,
- wherein the control circuit causes the feature extraction amplifier circuit to perform the feature extraction processing and fixes the gain set value of the amplifier circuit to the gain threshold value regardless of the volume set value, when the gain set value becomes equal to or greater than the gain threshold value.
Dependencies are inferred from the claim text.