Feature extraction of noise signal in motorcycle by Fast Fourier Transform

This research aimed to study the feature of noise signal from various exhausts in motorcycles by the Fast Fourier Transform (FFT). The noise signal was examined into three different features; energy, entropy, and zero-crossing rate. The energy and entropy defined the noise came from an exhaust or non-exhaust, while the zero-crossing rate distinguished normal and racing-exhaust. The results showed that the energy of an exhaust noise was always in the range of 2.4 to 2.8 joule. The entropy of exhausts racing was observed in the range of 0.00 to 0.05 joule. When the acceleration pedal was on, the entropy was become higher. The zero-crossing rate of racing exhaust was in the range of 0.00 to 0.05, the non-racing exhaust was in the range 0.05 to 0.1. (paper)