| 摘要 |
With interpolating processing for an input signal series xn by delay elements 111 to 11N, coefficient multiplying portions 120 to 12N and adders 131 to 13N, a fixed coefficient filter 11 outputs three signals, xn-M, Xn-M+1, and a midpoint x((n-M)T+T/2) between xn-M and Xn-M+1 obtained by delaying the input signal series xn. A selecting portion 211 selects two output signals from the above three signals according to time tau for obtaining an interpolated value under an instruction by a comparator 213. An interpolated value calculating portion 212 then performs linear interpolation between the two output signals selected by the selecting portion 211 according to the time tau for obtaining the interpolated value using a linear interpolation factor R set by the comparator 213, a switch 216 and a divider 217. This requires only a small number of coefficients to be stored in the interpolating device and no switching of coefficients for every change in time for obtaining the interpolated value, allowing high speed interpolating processing. <IMAGE> |
