| 摘要 |
PURPOSE:To estimate a frequency with a high accuracy by a high analyzing power even for a sound wave with a small pulse width by calculating the spectral peaks of frequency ranges divided from a plurality of data by the technique of maximum entropy method and averaging the peaks. CONSTITUTION:The signal wave x(t) of a sound wave received by a receiving element is A/D-converted 11 and stored in a RAM that is a first memory 12 as N pieces of data. Then, K pieces are taken out from the N pieces of the data and stored in a second memory 13. A resultant sequence of numbers is supplied to a spectral estimation calculator 14 using maximum entropy method and to a spectral peak detector 15 to obtain spectral peak positions. Thereafter, spectral peaks are averaged 10 and an obtained value is set as a sound source frequency.
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