DIGITAL FILTER DESIGN METHOD AND DEVICE, DIGITAL FILTER DESIGN PROGRAM, AND DIGITAL FILTER

摘要

For example, more than one FIR-type basic filters having a symmetric sequence of numbers having a predetermined characteristic as a filter coefficient are combined and connected in longitudinal connection. The filter coefficient is calculated and for the y-bit data of the calculated filter coefficient, the lower bit is cut off for rounding so as to obtain a filter coefficient of x-bit (x < y). Thus, it is possible to significantly reduce an unnecessary filter coefficient without performing the conventional window multiplication. Moreover, it is possible to realize a digital filter having a desired frequency characteristic with a small circuit size and with a high accuracy without causing a truncation error attributed to window multiplication in the frequency characteristic.