# getFrequencyVector

Get the vector of frequencies at which the short-time FFT is computed

Since R2020b

## Syntax

``freq = getFrequencyVector(stf)``
``freq = getFrequencyVector(stf,Fs)``

## Description

example

````freq = getFrequencyVector(stf)` returns the frequency vector at which the short-time FFT is computed. The input sample rate used is 2π.```

example

````freq = getFrequencyVector(stf,Fs)` returns the frequency vector assuming an input sample rate, `Fs`.```

## Examples

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Get the frequency vector at which the short-time FFT is computed.

Create a `dsp.STFT` object. The STFT object is defined with a `'twosided'` frequency range. The frequency vector is defined by the interval [0 Fs] and has the same length as the FFT length, where Fs is the input sample rate.

`stf = dsp.STFT`
```stf = STFT with properties: Window: [512x1 double] OverlapLength: 256 FFTLength: 512 FrequencyRange: 'twosided' ```

When the input sample rate Fs is not defined, the frequencies are computed in the interval [0, 2$\pi$].

Using the `getFrequencyVector` function, get the vector of frequencies at which the STFT is computed.

`freq = getFrequencyVector(stf)`
```freq = 512×1 0 0.0123 0.0245 0.0368 0.0491 0.0614 0.0736 0.0859 0.0982 0.1104 ⋮ ```

When the input sample rate Fs is defined, the frequency vector is defined by the interval [0 Fs].

```Fs = 44100; freqFs = getFrequencyVector(stf,Fs)```
```freqFs = 512×1 104 × 0 0.0086 0.0172 0.0258 0.0345 0.0431 0.0517 0.0603 0.0689 0.0775 ⋮ ```

## Input Arguments

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Short-time FFT object whose frequency vector is computed, specified as `dsp.STFT` object.

Input sample rate, specified as a real positive scalar. The STFT frequencies are computed in the interval determined by `Fs`. For more details, see `freq`.

Data Types: `single` | `double`

## Output Arguments

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Frequencies at which the short-time FFT is computed, returned as a column vector.

The length of the frequency vector is determined by the FrequencyRange property and the FFTLength.

If you set `FrequencyRange` to `'onesided'` and `FFTlength` is even, the frequency vector is of length `(FFTlength/2)+1`. If you set the `FrequencyRange` to `'onesided'` and `FFTlength` is odd, the frequency vector is of length `(FFTlength+1)/2`.

The frequencies cover the interval [0, `Fs`/2]. When `Fs` is not specified, the frequencies range from [0, π].

If you set the `FrequencyRange` property to `'twosided'`, the length of the frequency vector is equal to the value you specify in the `FFTlength` property. The frequencies cover the interval [0, `Fs`]. When `Fs` is not specified, the frequencies range from [0, 2π].

Data Types: `single` | `double`

## Version History

Introduced in R2020b