Changes

FSK is another radar technology and unlike CW and FMCW radars, transmitting freuqency is switched between at least two frequencies. Since the frequency changes is less than bandwidth of FMCW radars, Doppler shift effect of reflected target is the same but the phase is changed correlated with changes in target range .Range and velocity measuring is applicable for FSK radars. f1 and f2 in the below pictures corresponds to carrier frequencies of the radar sensor. Velocity information of target is pbtained from Doppler frequency however range is determined by comparing the phase of before and after frequency switched signals voltages.