| 摘要 |
PROBLEM TO BE SOLVED: To equally adjust an acoustic coupling between a speaker and microphones in a speech unit automatically and digitally by using the facility of the speech unit without the use of a particular unit. SOLUTION: The microphones MC1 to MC6 radially arranged are located at an equal distance from the speaker 16. A test signal generation section 258 in a digital signal processor (DSP) 25 outputs a test signal such as a pink noise signal to the speaker 16, digital gain attached A/D converters 271 to 273 inputs the signal of a microphone detecting the sound of the speaker 16 into the DSP 25, a level determination / gain control section 257 carries out gain adjustment processing and adjusts the digital gain in the A/D converters 271 to 273, a digital attenuation in a variable attenuation section 251, and a gain of a level outputted to an output amplifier 291 or the like on the basis of a result of the gain adjustment processing. COPYRIGHT: (C)2005,JPO&NCIPI |
