FSK means Frequency Shift Keying. It’s one of the Modulation Scheme used to Transmit Digital Data using High Frequency carrier signal. In this Modulation Scheme bit 1 is transmitted using one carrier signal and bit 0 is transmitted using another carrier signal like
· Bit 1 (logic high) is Transmitted using Carrier Frequency Fc1
· Bit 0 (logic low) is Transmitted using Carrier Frequency Fc2
It means Series of bits (bit stream) are transmitted with two different carrier signals used for bit 1 and bit 0.