Patent ID: 6889239
Filing Date: 2005-05-03
Classification: H03H

Abstract:
1. A digital filter for extracting a frequency component by multiplying a plurality of data constituting a data signal in which at least one “0” is inserted so as to carry out zero value interpolation by a plurality of coefficients, comprising; a plurality of delay circuits to shift the data signal; a first selection section to select one data other than the inserted “0” from the plurality of data included in the data signal; a second selection section to select one coefficient by which the data selected by the first selection section is multiplied, from the plurality of coefficients; a multiplication section to multiply the data selected by the first selection section by the coefficient selected by the second selection section; and an adding section to add multiplied results obtained by the multiplication section, wherein the first selection section selects one data each time the data signal is shifted, the second selection section selects one coefficient each time the data signal is shifted, and the first selection section selects the one data according to a first predetermined repeating sequence and the second selection section selects the one coefficient according to a second predetermined repeating sequence.