isfir

Determine if digital filter has finite impulse response

Syntax

flag =
isfir(d)

Description

flag = isfir(d) returns true if a digital filter, d, has a finite impulse response.

example

Examples

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FIR and IIR Digital Filters

Open Live Script

Use designfilt to design FIR and IIR versions of a sixth-order highpass filter. Specify a normalized stopband frequency of $0.3 π$ rad/sample and a normalized passband frequency of $0.6 π$ rad/sample. Verify that each filter is of the correct class.

fir = designfilt("highpassfir",FilterOrder=6, ...
    StopbandFrequency=0.3,PassbandFrequency=0.6);
isfirFIR = isfir(fir)

isfirFIR = logical
   1

iir = designfilt("highpassiir",FilterOrder=6, ...
    StopbandFrequency=0.3,PassbandFrequency=0.6);
isfirIIR = isfir(iir)

isfirIIR = logical
   0

Input Arguments

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`d` — Digital filter
`digitalFilter` object

Digital filter, specified as a digitalFilter object. Use designfilt to generate a digital filter based on frequency-response specifications.

Example: d = designfilt('lowpassiir','FilterOrder',3,'HalfPowerFrequency',0.5) specifies a third-order Butterworth filter with normalized 3 dB frequency 0.5π rad/sample.