Abstract
Keywords
Pure tone inside vehicle, tone to noise, objective rating, turbocharger, measurement.
Abstract
To quantify the annoyance of pure tone emitted inside vehicle, subjective assessments is an easy but not reliable solution. The turbocharger is one of the source producing pure tones in the cabin. A method based on the measurement has been developed to quantify its annoyance. An important stage of this method is the quantification of the tone itself in the background noise. Many factors can influence this result : the precise instantaneous frequency of the tone, the resolution of the spectrum, the position of the sensors. This paper presents some solutions to those issues. First, the exact frequency of the tone is extracted from the sonogram of an accelerometer which is perceptible to the turbocharger source. Then the Fast Fourier Transform analysis is replaced by a Pseudo Smoothed Wigner Ville Distribution. At last the number of microphone is optimized. With those solutions, the method which is used to quantify the annoyance gives robust results in any conditions of measurement.