gffilter

R2026b

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).

Examples

Filter Data Sequence Over Galois Field

Define the input data sequence, and the numerator and 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.

Tips

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

Version History

Introduced before R2006a