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Doppler Shift Calculator
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Doppler Shift (or Doppler Effect) is the change in frequency of the a wave observed when the observer is in motion relative to the source of the wave.

Doppler Shift Formula -
$\lambda_{f} = \frac{v -u_{s}}{f_{0}}$
Where, $\lambda_{f}$ is the 'Wavelength in Front of a Moving Source', v is the 'Wave Velocity', $u_{s}$ is the source velocity, ${f_{0}}$ is the source frequency.

Doppler Shift Calculator (Doppler Effect Calculator) is an online tool for calculating values of the unknown parameters in the Doppler Shift Formula provided other parameters are known.

 

Step by Step Calculation

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Step 1 :  

Doppler Effect is the change in frequency and wavelength of a wave for an observer moving relative to the source of the waves.


Formula:


Wavelength in Front of a Moving Source:


λf = (v - us) / f0


Wave Velocity:


v = (λf * f0) + us


Source Velocity:


us = v - (λf * f0)


Source Frequency:


f0 = (v - us) / λf



Step 2 :  

State the equation you plan to use and plug in the values.



Example Problems

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  1. A train passes a passenger platform at a speed 92 m/s of wave velocity with moving source 2.6 m. The horn sounds at 32 Hz. Calculate the source velocity?


    Step 1 :  

    The given:


    Wavelength in Front of a Moving Source (λf) = 2.6 m.


    Wave Velocity (v) = 92 m/s


    Source frequency (f0) =32 Hz.


    Source velocity (us) = ?



    Step 2 :  

    Plug the values in the formula.


    Source Velocity:


    us = v - λf * f0 .


    us = 920 - (2.6 * 320)



    Answer  :  

    us = 8.800 Hz



  2. A train passes a passenger platform at a speed of 40 m/s. The horn sounds at 320 Hz. What frequency is heard by a person on the platform as the train approaches? 


    Step 1 :  

    The given:


    where λf = 220 Hz
    v = 340 m/s
    us = +40 towards



    Step 2 :  

    Plug the values in the formula.


    Source Frequency:


    f0 = (v - us) / λf


    f0 = (340 - (+40)) / 220


    f0 = (340 - 40) / 220


    f0 = 300 / 220



    Answer  :  

    f0 = 1.364 Hz.



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