Interpolating non-recursive digital filter

Abstract From the Canadian patent

In the known interpolating digital filters with interpolation factor r where N input signal samples are processed, sets of multiplication factors a m,k with m = 0 1, 2, ...r-1 are used, the elements a(m,k) with k = 0 1, 2, ....N-1 of which are each equal in magnitude to instantaneous values of the pulse response. The products obtained by multiplying the N input signal samples and the N elements a(m,k) of a set am,k are added together and the result of this addition is read out, whereafter the adder device is reset to its zero position; that is to say periodically with the output sampling frequency. In the interpolating digital filter represented here sets of multiplication factors b m,k …