FILTER COEFFICIENT GROUP COMPUTATION DEVICE AND FILTER COEFFICIENT GROUP COMPUTATION METHOD

摘要

A filter coefficient group computation device is configured from a means for performing inverse Fourier transform on a frequency characteristic inputted through an input means; a means for performing short-term Fourier transform on a numerical string obtained by the inverse Fourier transform; a means for performing windowing on a frequency domain signal, obtained by the short-term Fourier transform, using a function of which a window length shortens as frequency increases; a means for performing short-term inverse Fourier transform on the frequency domain signal after the windowing; a means for performing overlap addition on a numerical string obtained by the short-term inverse Fourier transform; and a means for determining a numerical string after the overlap addition as a filter coefficient group which forms a filter having the frequency characteristic inputted through the input means.

主权项

1. A filter coefficient group computation device, provided with an input unit on which a user inputs a frequency characteristic and configured to compute a filter coefficient group which forms a filter having a frequency characteristic inputted through the input unit, comprising:
an inverse Fourier transform unit configured to perform inverse Fourier transform on the frequency characteristic inputted through the input unit; a short-term Fourier transform unit configured to perform short-term Fourier transform on a numerical string obtained by the inverse Fourier transform; a windowing unit configured to perform windowing on a frequency domain signal, obtained by the short-term Fourier transform, using a function of which a window length shortens as frequency increases; a short-term inverse Fourier transform unit configured to perform short-term inverse Fourier transform on the frequency domain signal after the windowing; an overlap addition unit configured to perform overlap addition on a numerical string obtained by the short-term inverse Fourier transform; and a filter coefficient group determination unit configured to determine a numerical string after the overlap addition as the filter coefficient group which forms the filter having the frequency characteristic inputted through the input unit.