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# fir_pmord (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

[n, fb, ab, w] = fir_pmord(f, a, ripple)

[n, fb, ab, w] = fir_pmord(f, a, ripple, fs)

Legacy Name: `firpmord`

## Description

Returns the order and normalized frequencies of the lowest order linear phase FIR filter with a given specification. The designed filter is an optimal equiripple filter that uses the Parks-McClellan algorithm.

Examples

## Inputs

Name Description
f Specifies the cutoff frequencies of the filter. f is a vector of increasing positive numbers in the interval [0, fs/2].
a Specifies the desired magnitudes at the f frequencies. a is a real vector.
ripple Specifies the maximum deviation of ripples per band. ripple is a real vector.
fs Specifies the sampling frequency. fs is a positive number. The default is 2.

## Outputs

Name Description
n Returns the estimated filter order. n is a positive integer.
fb Returns the normalized frequencies corresponding to f. fb is a real vector of increasing values in the interval [0, 1].
ab Returns the magnitudes of the filter. ab is a real vector of the same size as fb.
w Returns the weights of the filter. w is a vector of positive numbers of the same size as fb.

## 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

F = [100, 200];
A = [0, 1];
RIPPLE = [0.05, 0.02];
FS = 500;
[N, FB, AB, W] = fir_pmord(F, A, RIPPLE, FS)

## Related Topics

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