| 摘要 |
PROBLEM TO BE SOLVED: To effectively damp noises in a stationary noise field where noise sources cannot be specified. SOLUTION: The active type silencer 1 comprises a speaker 2, a microphone 3, an analog-to-digital converter 4, a controller 5 and a digital-to-analog converter 6. The controller 5 is internally provided with a CPU 7 and a memory 8. The CPU 7 separates the tones collected from the microphone 3 to the noises and the output tones from the speaker 2, estimates the waveforms of the noises, predicts the waveforms of the next noises, forms the muffling tones of the anti-phase from the waveforms of the noises and outputs the tones removed of the tones by as much as the number of the samples corresponding to the propagation timeτof the tones between the speaker and the microphone. COPYRIGHT: (C)2003,JPO |
