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# fir_pm (MathScript RT Module Function)

LabVIEW 2011 MathScript RT Module Help

Edition Date: June 2011

Part Number: 373123B-01

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Owning Class: filter design

Requires: MathScript RT Module

## Syntax

b = fir_pm(n, f, a)

b = fir_pm(n, f, a, filter)

b = fir_pm(n, f, a, w)

b = fir_pm(n, f, a, w, filter)

[b, ripple] = fir_pm(n, f, a)

[b, ripple] = fir_pm(n, f, a, filter)

[b, ripple] = fir_pm(n, f, a, w)

[b, ripple] = fir_pm(n, f, a, w, filter)

Legacy Name: `firpm`

## Description

Designs a linear phase, equiripple, FIR filter using the Parks-McClellan algorithm. This function is equivalent to the fir_remez function.

Examples

## Inputs

Name Description
n Specifies the filter order. n is a positive integer. n must be even for filters with a non-zero gain at the Nyquist frequency. If n does not meet this condition, LabVIEW increases n by 1.
f Specifies the frequencies. f is a real vector of increasing values in the interval [0, 1]. 0 and 1 must be in f. 1 represents the Nyquist frequency.
a Specifies the magnitudes at the f frequencies. a is a real vector of the same size as f.
filter Specifies the odd-symmetry filter to design. filter is a string that accepts the following values.

 'differentiator' Designs a differentiator filter. 'Hilbert' Designs a Hilbert filter.
w Specifies the weights that correspond to f and a. Each band has exactly one weight. The size of w is half the size of f. w is a vector of positive numbers.

## Outputs

Name Description
b Returns the filter coefficients of order n. b is a real vector.
ripple Returns the maximum ripple size of the filter. ripple is a positive number.

## Details

The following table lists the support characteristics of this function.

 Supported in the LabVIEW Run-Time Engine Yes Supported on RT targets Yes Suitable for bounded execution times on RT Not characterized

## Examples

N = 13;
F = [0, 0.1, 0.5, 0.7, 0.8, 1];
A = [0, 1, 1, 1, 0, 0];
W = [1, 10, 1];
B = fir_pm(N, F, A, W)

## Related Topics

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