Patent ID: 7590675

Claim:
A method of providing filter coefficients for a digital filter, comprising: a first step of generating a first filter coefficient of a symmetric numeric string; a second step of obtaining a second filter coefficient of the symmetric numeric ring by realizing a second frequency-amplitude characteristic having a contact point at a position where a maximum value is acquired in a first frequency-amplitude characteristic expressed by said first filter coefficient and having a minimum value at said contact point; and a third step of executing a calculation to obtain a third filter coefficient of the symmetric numeric ring obtained when a first filter having said first filter coefficient and a second filter having said second filter coefficient are cascaded, wherein said third filter coefficient generated in said third step is determined as the filter coefficient to be obtained, and wherein, said digital filter multiplies the plurality of filter coefficients with signals at taps of a tapped delay line made up of a plurality of delayers, sums up the multiplication results and outputs the sum.