gffilter

Filter data using polynomials over prime Galois field

Syntax

y = gffilter(b,a,x)

y = gffilter(b,a,x,p)

Description

y = gffilter(b,a,x) filters the data in vector x with the filter described by vectors b and a.

y = gffilter(b,a,x,p) filters the data x using the filter described by vectors a and b. y is the filtered data in GF(p).

Note

This function performs computations in GF(p^m), where p is prime. To work in GF(2^m), use the filter function with Galois arrays. For details, see Filtering.

Examples

Filter Data Sequence Over Galois Field

Define the input data sequence and the numerator denominator coefficients of the filter.

b = [1 0 0 1 0 1 0 1];
a = [1 0 1 1];
x = [1,zeros(1,19)];

Filter the input sequence.

y = gffilter(b,a,x)

y = 1×20

     1     0     1     0     1     0     1     0     1     1     1     0     0     1     0     1     1     1     0     0

Plot the result.

stem(y);
axis([0 20 -.1 1.1])

Input Arguments

x — Input data

row vector | column vector

Input data to be filtered, specified as a row vector or a column vector.

Data Types: double

b — Numerator coefficients of filter

row vector | column vector

Numerator coefficients of the filter, specified as a row vector or a column vector.

Data Types: double

a — Denominator coefficients of filter

row vector | column vector

Denominator coefficients of the filter, specified as a row vector or a column vector.

Data Types: double

p — Prime number

2 (default) | scalar prime number

Prime number, specified as a scalar prime number.

Data Types: double

Output Arguments

y — Filtered output data

row vector

Filtered output data, returned as a row vector of the polynomial coefficients in order of ascending powers.

Version History

Introduced before R2006a