# speed2dop

Convert speed to Doppler shift

## Syntax

```Doppler_shift = speed2dop(radvel,lambda) ```

## Description

`Doppler_shift = speed2dop(radvel,lambda)` returns the one-way Doppler shift in hertz corresponding to the radial velocity, `radvel`, for the wavelength `lambda`.

## Examples

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Calculate the Doppler shift in hertz for a given carrier wavelength and source speed. The radar frequency is 24.15 GHz. Assume a radial speed of 35.76 m/s.

```radvel = 35.76; f0 = 24.15e9; lambda = physconst('LightSpeed')/f0; doppler_shift = speed2dop(radvel,lambda)```
```doppler_shift = 2.8807e+03 ```

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The Doppler shift of a source relative to a receiver can be computed from the relative radial velocity between the source and receiver:

`$\Delta f=\frac{{V}_{s,r}}{\lambda }$`

where Δf is the Doppler shift in hertz, Vs,r denotes the radial velocity of the source relative to the receiver, and λ is the carrier frequency wavelength in meters.

## References

 Rappaport, T. Wireless Communications: Principles & Practices. Upper Saddle River, NJ: Prentice Hall, 1996.

 Skolnik, M. Introduction to Radar Systems, 3rd Ed. New York: McGraw-Hill, 2001.