# freq2wavelen

Convert frequency to wavelength

Since R2021a

## Syntax

``wavelen = freq2wavelen(freq)``
``wavelen = freq2wavelen(freq,c)``
``[wavelen,c] = freq2wavelen(___)``

## Description

example

````wavelen = freq2wavelen(freq)` converts the frequency `freq` to the wavelength `wavelen` using the speed of light in a vacuum.```

example

````wavelen = freq2wavelen(freq,c)` also specifies the signal propagation speed `c`.```

example

````[wavelen,c] = freq2wavelen(___)` also returns the propagation speed `c` used to compute wavelength `wavelen`.```

## Examples

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Calculate the wavelengths corresponding to frequencies of 3 and 4 GHz. Use the default speed of propagation.

```freq = [3e9,4e9]; lambda = freq2wavelen(freq)```
```lambda = 1×2 0.0999 0.0749 ```

Calculate the wavelength corresponding to a frequency of 4 GHz. Obtain the propagation speed used to compute the wavelength.

```freq = 4e9; [lambda,c] = freq2wavelen(freq,3.0e8)```
```lambda = 0.0750 ```
```c = 300000000 ```

## Input Arguments

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Signal frequency, specified as a positive scalar or a length-M vector of positive values. Units are in Hz.

Example: `10e6`

Data Types: `double`

Signal propagation speed, specified as a positive scalar. The default value is obtained from `physconst('Lightspeed')`. Units are in m/s.

Example: 3.0e8

Data Types: `double`

## Output Arguments

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Signal wavelength, returned as a positive scalar or length-M vector of positive values. The size of `wavelen` equals the size of `freq`. Units are in meters.

Signal propagation speed, returned as a positive scalar. Units are in m/s.

Data Types: `double`

## Version History

Introduced in R2021a