Source identification by the coherence analysis of transient sound radiation

Recent theoretical development in the field of partial coherence analysis of multiple input systems is reviewed. Relevant computational procedures for applying this theory to identifying sound radiation from transient noise sources are presented briefly. The procedures are used to analyse a tape recording of the surface acceleration and radiated noise of a punch press. Several multiple input systems are formed and analysed both with and without time delay compensation. The multiple coherences show that the chosen inputs represent well the sound radiation at frequencies of interest. The punch was found to be the dominating source at low frequencies. At higher frequencies also other sources could be identified.