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Inverse discrete Fourier transform (IDFT)

The `dsp.IFFT`

System
object™ computes the inverse discrete Fourier transform (IDFT) of the input. The object
uses one or more of the following fast Fourier transform (FFT) algorithms depending on the
complexity of the input and whether the output is in linear or bit-reversed order:

To compute the IFFT of the input:

Create the

`dsp.IFFT`

object and set its properties.Call the object with arguments, as if it were a function.

To learn more about how System objects work, see What Are System Objects? (MATLAB).

`ift = dsp.IFFT`

`ift = dsp.IFFT(Name,Value)`

returns an `ift`

= dsp.IFFT`IFFT`

object, `ift`

, that computes the IDFT
of a column vector or *N*-D array. For column vectors or N-D arrays, the
`IFFT`

object computes the IDFT along the first
dimension of the array. If the input is a row vector, the `IFFT`

object computes a row of single-sample IDFTs and issues a
warning.

returns an `ift`

= dsp.IFFT(`Name,Value`

)`IFFT`

object, `ift`

, with
each property set to the specified value. Enclose each property name in single quotes.
Unspecified properties have default values.

**For versions earlier than R2016b, use the step
function to run the System object algorithm. The arguments to
step are the object you created, followed by
the arguments shown in this section.**

**For example, y = step(obj,x) and y = obj(x) perform equivalent operations.**

`y = ift(x)`

To use an object function, specify the
System
object as the first input argument. For
example, to release system resources of a System
object named `obj`

, use
this syntax:

release(obj)

This object implements the algorithm, inputs, and outputs described on the IFFT block reference page. The object properties correspond to the block
parameters, except the **Output sampling mode** parameter is not supported by
`dsp.IFFT`

.

[1] FFTW (`http://www.fftw.org`

)

[2] Frigo, M. and S. G. Johnson, “FFTW: An Adaptive Software
Architecture for the FFT,” *Proceedings of the International Conference on
Acoustics, Speech, and Signal Processing*, Vol. 3, 1998, pp. 1381-1384.