Digital filter system
First Claim
1. A digital filter system which can vary at least one of position and width of a pass band thereof, comprising:
- a digital filter for filtering an input digital signal in accordance with filter coefficients {ak1, ak2, b00, bk1, bk2, c and d} (k=1, 2, . . . , N/2;
N is an even number), and for outputting the filtered signal;
calculation means for calculating each of the filter coefficients {ak1, ak2, b00, bk1, bk2, c and d} in accordance with equations (48) to (54) by using pass band position data x and pass band width data y; and
setting means for setting the filter coefficients calculated by said calculation means to said digital filter;
##EQU13## "L" and "M" are the orders for the approximation, and Pb00i, Qb00j, Pbk1i, Qbk1j, Pbk2i, Qbk2j, Pak1i, Qak1j, Pak2i, Qak2j, Pci, Qcj, Pdi and Qdj are constants.
1 Assignment
0 Petitions
Accused Products
Abstract
Constants {Pb00i, Qb00j, . . . , Pak2i, Qak2j, Pci, Qcj, Pdi, and Qdj } for calculating each of filter coefficients {ak1, ak2, b00, bk1, bk2, c and d} for a digital filter 15 by using non-linear polynomials for pass band position data x and pass band width data y are stored in a memory 13. The constants {Pb00i, Qb00j, . . . , Pak2i, Qak2j, Pci, Qcj, Pdi, and Qdj } are determined by using the least square method so that the sum of the square of the errors between the filter coefficients calculated by using non-liner polynomials and the filter coefficients of digital filter having known characteristics becomes the least or the minimum. A CPU 11 calculates the filter coefficients non-linearly by using the constants stored in the memory 13, and sets the results to the digital filter 15 when new pass band position data x or pass band width data y is input at knobs SC and SW.
-
Citations
10 Claims
-
1. A digital filter system which can vary at least one of position and width of a pass band thereof, comprising:
-
a digital filter for filtering an input digital signal in accordance with filter coefficients {ak1, ak2, b00, bk1, bk2, c and d} (k=1, 2, . . . , N/2;
N is an even number), and for outputting the filtered signal;calculation means for calculating each of the filter coefficients {ak1, ak2, b00, bk1, bk2, c and d} in accordance with equations (48) to (54) by using pass band position data x and pass band width data y; and setting means for setting the filter coefficients calculated by said calculation means to said digital filter;
##EQU13## "L" and "M" are the orders for the approximation, and Pb00i, Qb00j, Pbk1i, Qbk1j, Pbk2i, Qbk2j, Pak1i, Qak1j, Pak2i, Qak2j, Pci, Qcj, Pdi and Qdj are constants. - View Dependent Claims (2, 3, 4, 5, 6)
-
-
7. A digital filter system which can vary at least one of a position and a width of a pass band thereof, comprising:
-
a digital filter for filtering an input digital signal in accordance with a filter coefficient FCh (h=1, 2, . . . , n;
n is a natural number), and for outputting the filtered signal;calculation means for calculating the filter coefficient FCh in accordance with equation (56) with pass band position data x and pass band width data y; and setting means for setting the filter coefficient FCh calculated by said calculation means, to said digital filter;
##EQU15## "L" and "M" are orders, and Shi and Thj are predetermined constants. - View Dependent Claims (8, 9)
-
-
10. A digital filter system comprising:
-
a digital filter for filtering an input digital signal in accordance with filter coefficients, and for outputting the filtered signal; parameter storage means for storing parameters for calculating said filter coefficients which are defined by a non-linear polynomial for a position and/or a width for a pass band of said digital filter; filter coefficient calculation means for calculating the filter coefficients, based on the parameters stored in said parameter storage means, and the position and/or width of the pass band of said digital filter; and setting means for setting the filter coefficients calculated by said filter coefficient calculation means to said digital filter.
-
Specification