Apparatus and method for designing a digital filter, digital filter design program, digital filter

摘要

For example, a filter coefficient is calculated when cascaded by arbitrarily combining one or more FIR type basic filters having a symmetric numerical sequence having a predetermined characteristic as a filter coefficient, and y bits of the calculated filter coefficient are calculated. By performing rounding processing that rounds down the lower-order bits of the data, the filter coefficient of x bits (x y) is obtained, so that unnecessary filter coefficients can be greatly increased without performing conventional windowing. The digital filter having the desired frequency characteristic can be realized with high accuracy with a small circuit scale by making it possible to reduce the frequency characteristic and preventing a truncation error due to windowing in the frequency characteristic.