isfir

Determine if digital filter has finite impulse response

Syntax

``````flag = isfir(d)``````

Description

example

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

Examples

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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

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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

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Filter class identification, returned as a logical scalar.

Version History

Introduced in R2014a