filter

1-D digital filter

📝 Syntax

• y = filter(b, a, x)

📥 Input argument

• b - Numerator coefficients of rational transfer function: vector.

• a - Denominator coefficients of rational transfer function: vector.

• x - Input data: matrix.

📤 Output argument

• y - Filtered data: matrix.

📄 Description

The functionfilter(b, a, x) applies a rational transfer function to filter the input data arrayx.

This transfer function is defined by the coefficients of the numerator (b) and denominator (a).

If the first coefficient ofa (a(1)) is not equal to 1, the filter normalizes the coefficients by a(1). It is crucial for a(1) to be nonzero.

Whenx is a vector, the function returns a vector of the same size asx containing the filtered data.

💡 Example

f = figure();
rng default
t = linspace(-pi,pi,100);
X = sin(t) + (0.33 * rand(size(t)));
windowSize = 7;
b = (1/windowSize)*ones(1,windowSize);
a = 1;
y = filter(b, a, X);
plot(t, X)
hold on
plot(t, y)
legend(_('Input Data'), _('Filtered Data'));

🔗 See also

conv.

🕔 History

Version	📄 Description
1.0.0	initial version