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 highpass filter. Specify a normalized stopband frequency of 0.3 and a normalized passband frequency of 0.6. Verify that each filter is of the correct class. Display the frequency responses of the filters.

fir = designfilt('highpassfir','StopbandFrequency',0.3,'PassbandFrequency',0.6);
iir = designfilt('highpassiir','StopbandFrequency',0.3,'PassbandFrequency',0.6);
isfirFIR = isfir(fir)

isfirFIR = logical
   1

isiirFIR = isfir(iir)

isiirFIR = logical
   0

fvt = fvtool(fir,iir);
legend(fvt,'FIR','IIR')

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.