Doppler Frequency Equation Formula

Equation for calculate doppler frequency equation is,

$$x=\mathrm{2v}\times \frac{\mathrm{f_t}}{\mathrm{(c-v)}}$$

where,
c = the speed of light through a vacuum (299792458 m/s)
v = the target velocity
f_t = original frequency
f_d = Doppler frequency