Speech communication apparatus
First Claim
1. A speech communication apparatus for bi-directional speech communications, comprising:
- a speaker;
a microphone;
background sound level measurement means for extracting background sound from the output of the microphone and for measuring the level of the extracted background sound; and
received-speech clarifying means for adjusting a gain for the received speech to be output to the speaker according to the level of the background sound measured by the background sound level measurement means.
1 Assignment
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Accused Products
Abstract
A transmission-speech extraction filter extracts speech to be transmitted from the output signal of a transmission-speech microphone by using the proximity effect. A background-sound extraction filter extracts background sound from the output signal of the transmission-speech microphone. A background sound level calculation section calculates the level of the extracted background sound in each frequency band, and sends the level to a loudness-compensation control section as a background-sound level. The loudness-compensation control section controls the amount of gain adjustment for a received-speech signal in each frequency band in a gain adjustment section according to the background-sound level and the received-speech level of a received-speech signal, calculated in a received-speech-level calculation section.
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Citations
20 Claims
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1. A speech communication apparatus for bi-directional speech communications, comprising:
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a speaker;
a microphone;
background sound level measurement means for extracting background sound from the output of the microphone and for measuring the level of the extracted background sound; and
received-speech clarifying means for adjusting a gain for the received speech to be output to the speaker according to the level of the background sound measured by the background sound level measurement means. - View Dependent Claims (2, 3)
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4. A speech communication apparatus for bi-directional speech communications, comprising:
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a speaker;
a microphone;
background sound level measurement means for manipulating the frequency characteristic of the output of the microphone to minimize the proximity effect produced in the output of the microphone to extract speech to be transmitted from the output of the microphone, and for measuring the level of background sound according to the extracted speech to be transmitted; and
received-speech clarifying means for adjusting a gain for the received speech to be output to the speaker according to the level of the background sound measured by the background sound level measurement means. - View Dependent Claims (5, 6, 7)
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8. A speech communication apparatus comprising:
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a speaker;
a microphone;
a background sound microphone;
a transmission speech filter operable to reduce the level of a lower frequency component outputted by the microphone;
an adaptive filter operable to estimate speech signals outputted by the background sound microphone;
an adder operable to subtract the estimated speech signal from the output of the background sound microphone;
a background sound level calculator operable to calculate the level of the signal outputted from the adder and the level of the background sound;
a background sound level filter operable to minimize proximity effect; and
a received speech clarifying filter operable to adjust the gain for received speech according to the background sound level. - View Dependent Claims (9)
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10. A speech communication apparatus for bi-directional speech communications, provided with a handset having at a front face a speaker for outputting received speech and a transmission-speech microphone for collecting speech to be transmitted, the speech communication apparatus comprising:
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a background-sound microphone disposed at the rear face of the handset at almost the same height as the speaker, for collecting background sound;
background sound level measurement means for measuring the level of the output of the background-sound microphone as a background-sound level; and
received-speech clarifying means for adjusting a gain for received speech output to the speaker according to the background-sound level measured by the background sound level measurement means. - View Dependent Claims (11, 12, 13)
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14. A speech communication apparatus for bi-directional speech communications, comprising:
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a speaker for outputting received speech;
a microphone for collecting speech to be transmitted;
background sound level measurement operable to measure the level of background sound; and
received-speech clarifying section operable to adjust a gain for the received speech to be outputted to the speaker according to the level of the background sound measured by the background sound level measurement means, the background sound level measurement calculator comprising;
a delay section operable to delay the output of the first background-sound microphone by the period corresponding to the delay time between transmission speech mixed into the output of the first background-sound microphone and transmission speech mixed into the output of the second background-sound microphone, an adaptive filter operable to estimate transmission speech mixed into the output of the delay section, an adder operable to subtract the transmission speech estimated by the adaptive filter from the output of the delay means, and background sound level calculation section operable to calculate the level of the output of the subtracting means and for outputting the result as the level of the background sound. - View Dependent Claims (15, 16, 17)
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18. A speech communication method for bi-directional speech communications, comprising the acts of:
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manipulating the frequency characteristic of the output of a microphone for collecting speech to be transmitted in order to diminish the proximity effect produced in the output of the microphone to extract speech to be transmitted from the output of the microphone;
measuring the level of background sound according to the extracted speech to be transmitted; and
adjusting a gain for received speech to be outputted to the speaker according to the measured level of the background sound. - View Dependent Claims (19, 20)
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Specification