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.

Examples

FIR and IIR Digital Filters

Use designfilt to design FIR and IIR versions of a sixth-order highpass filter. Specify a normalized stopband frequency of $0.3\pi$ rad/sample and a normalized passband frequency of $0.6\pi$ 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

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.

Output Arguments

flag — Filter class identification

logical scalar

Filter class identification, returned as a logical scalar.

Version History

Introduced in R2014a