ACTIVE MUFFLER AND ITS SIGNAL PROCESSING METHOD

摘要

PROBLEM TO BE SOLVED: To solve such problem that a filter being the sound field characteristic between a speaker and an error microphone or between the speaker and a reference sensor is used as a kind of a constant while previously fixing the field characteristic and therefore, the filter can not appropriately be identified when the sound field characteristic is varied in a conventional active muffler. SOLUTION: Engine sound being a noise source and M group signals being random signals independently generated of the engine sound are detected by an error microphone 2 or a reference sensor 1 both of which are detectors. Detected signals are inputted into a signal processor 11 and signals having correlation with the engine sound are eliminated by the processor 11. Then, adaptive filters C'.H' provided between a speaker 4 and the microphone 2 or the speaker 4 and the reference sensor 1 are identified by the signals in which signals having correlation with the engine sound are eliminated.