摘要 |
Filter coefficients corresponding to a plurality of discrete cutoff frequencies are stored in advance in a memory and a filter coefficient corresponding to a specified cutoff frequency is generated by performing an interpolation referring to the filter coefficients stored in the memory, thereby saving the capacity of the memory. When a resonance index is to be specified in addition to the cutoff frequency, filter coefficients corresponding to two difference resonance indexes are acquired by the interpolation, then a new filter coefficient is acquired by executing the interpolation referring to these two filter coefficients.
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