# digitalFilter

Digital filter

**The Coefficients property has been replaced by the
Numerator and Denominator properties. For more
information, see Version History.**

## Description

Use `designfilt`

to design and edit
`digitalFilter`

objects.

Use

`designfilt`

in the form`d = designfilt(resp,Name,Value)`

to design a digital filter`d`

with response type`resp`

. Customize the filter using name-value arguments.Use

`designfilt`

in the form`designfilt(d)`

to edit an existing filter,`d`

.**Note**This is the only way to edit an existing

`digitalFilter`

object. Its properties are otherwise read-only.Use

`filter`

in the form`dataOut = filter(d,dataIn)`

to filter a signal with a`digitalFilter`

`d`

. The input can be a double- or single-precision vector. It can also be a matrix with as many columns as there are input channels. You can also use the`filtfilt`

and`fftfilt`

functions with`digitalFilter`

objects.Use Filter Analyzer to visualize a

`digitalFilter`

.

## Properties

## Object Functions

**Filtering**

**Filter Analysis**

`double` | Cast coefficients of digital filter to double precision |

`filt2block` | Generate Simulink filter block |

`filtord` | Filter order |

`firtype` | Type of linear phase FIR filter |

`freqz` | Frequency response of digital filter |

`grpdelay` | Average filter delay (group delay) |

`impz` | Impulse response of digital filter |

`impzlength` | Impulse response length |

`info` | Information about digital filter |

`isallpass` | Determine whether filter is allpass |

`isdouble` | Determine if digital filter coefficients are double precision |

`isfir` | Determine if digital filter has finite impulse response |

`islinphase` | Determine whether filter has linear phase |

`ismaxphase` | Determine whether filter is maximum phase |

`isminphase` | Determine whether filter is minimum phase |

`issingle` | Determine if digital filter coefficients are single precision |

`isstable` | Determine whether filter is stable |

`phasedelay` | Phase delay of digital filter |

`phasez` | Phase response of digital filter |

`single` | Cast coefficients of digital filter to single precision |

`ss` | Convert digital filter to state-space representation |

`stepz` | Step response of digital filter |

`tf` | Convert digital filter to transfer function |

`zerophase` | Zero-phase response of digital filter |

`zpk` | Convert digital filter to zero-pole-gain representation |

`zplane` | Zero-pole plot for discrete-time systems |

## Examples

## More About

## References

[1] Lyons, Richard
G. *Understanding Digital Signal Processing*. Upper Saddle River, NJ:
Prentice Hall, 2004.

## Version History

**Introduced in R2014a**

## See Also

### Live Editor Tasks

### Apps

### Objects

### Functions

`bandpass`

|`bandstop`

|`highpass`

|`lowpass`

|`designfilt`

|`double`

|`ctffilt`

|`fftfilt`

|`filt2block`

|`filter`

|`filtfilt`

|`filtord`

|`firtype`

|`freqz`

|`grpdelay`

|`impz`

|`impzlength`

|`info`

|`isallpass`

|`isdouble`

|`isfir`

|`islinphase`

|`ismaxphase`

|`isminphase`

|`issingle`

|`isstable`

|`phasedelay`

|`phasez`

|`single`

|`ss`

|`stepz`

|`tf`

|`zerophase`

|`zpk`

|`zplane`