# impz: Impulse-response characteristics In signal: Signal Processing

 impz R Documentation

## Impulse-response characteristics

### Description

Impulse-response characteristics of a discrete filter.

### Usage

``````## Default S3 method:
impz(filt, a = 1, n = NULL, Fs = 1, ...)

## S3 method for class 'Arma'
impz(filt, ...)

## S3 method for class 'Ma'
impz(filt, ...)

## S3 method for class 'impz'
plot(x, xlab = "Time, msec", ylab = "", type = "l",
main = "Impulse response", ...)

## S3 method for class 'impz'
print(x, xlab = "Time, msec", ylab = "", type = "l",
main = "Impulse response", ...)
``````

### Arguments

 `filt` for the default case, the moving-average coefficients of an ARMA model or filter. Generically, `filt` specifies an arbitrary model or filter operation. `a` the autoregressive (recursive) coefficients of an ARMA filter. `n` number of points at which to evaluate the frequency response. `Fs` sampling frequency in Hz. If not specified, the frequencies are in per unit. `...` for methods of `impz`, arguments are passed to the default method. For `plot.impz`, additional arguments are passed through to `plot`. `x` object to be plotted. `xlab`, `ylab`, `main` axis labels anmd main title with sensible defaults. `type` as in `plot`, uses lines to connect the points

### Details

When results of `impz` are printed, the impulse response will be plotted. As with `lattice` plots, automatic printing does not work inside loops and function calls, so explicit calls to `print` or `plot` are needed there.

### Value

For `impz`, a list of class `impz` with items:

 `x` impulse response signal. `t` time.

### Author(s)

Original Octave version by Kurt Hornik and John W. Eaton. Conversion to R by Tom Short.

### References

Octave Forge https://octave.sourceforge.io/

`filter`, `freqz`, `zplane`
``````bt <- butter(5, 0.3)