Patent ID: 7076512

Claim:
A digital filter device for increasing a sampling rate and reconstructing signals of discrete-time input data, the digital filter device comprising: n filter stages disposed in series and each having a filter stage input and a latch connected to said filter stage input, said latch doubling the sampling rate by outputting each input data value twice, each of said n filter stages having a filter structure disposed downstream of said latch and having a partial transfer function {overscore (H)} (z) defined by {overscore (H)} ( z )âˆ(1+ z âˆ’1 ) kâˆ’1 ; and a transfer function H(z) of the digital filter device being H â¡ ( z ) âˆ ( 1 - z - ( 2 n ) 1 - z - 1 ) k , where k is an order of the digital filter device and 2 n is a factor of an increase in the sampling rate and z âˆ’1 is a z transform of a delay by one sampling pulse.