Ontology-Based Noise Source Identification and Key Feature Selection: A Case Study on Tractor Cab

Table 3

Peak frequency (Hz).

Working condition (rotation speed: rpm)	Engine				In the cab				Air filter	Muffler	Back panel	At operator’s position
	1	2	3	4	5	6	7	8				Near left ear
700	349	—	500	—	349	—	349	349	—	—	349	349
2400	349	349	500	275	349	—	475	475	410	410	349	349