FSK (Frequency Shift Keying)

It is the Modulation Technique in which Amplitude and Phase of Signal are kept Constant while frequency is varies to represent binary 1 or 0.One level of frequency represents binary 1 and other represents binary 0.The main advantage of using this technique is that it is less prone to noise and sender is only concerned about the frequency and not about the amplitude.

Figure given Below clearly illustrates FSK.where one level of frequency is representing binary 1 and another level is representing binary 0.