Patent ID: 7574005

Claim:
A method of emphasizing a peak frequency component of a sound signal inputted during an observation period having a predetermined length, the method comprising the steps of: successively sampling the sound signal to provide a running set of samples of the sound signal inputted during the observation period such that a total number of the samples in the running set increments each time one or more of new sample is added to the running set until the total number of the samples corresponds to the predetermined length of the observation period; recurrently calculating a running frequency characteristic of the sound signal on a common frequency axis for the observation period from the running set of the samples each time one or more of new sample is added to the running set; accumulating the recurrently calculated running frequency characteristics on the common frequency axis so as to emphasize a peak frequency component contained in the sound signal; and outputting a frequency spectrum representing the emphasized peak frequency component based on the accumulated running frequency characteristics.