spread frequency shift keying (S-FSK)

Spread Frequency Shift Keying (S-FSK) is a spread band( SS) keying technique used in Powerline Communication( PLC) that has lower interference in narrowband transmission than normal frequency shift keying (FSK).

S-FSK keying is described in IEC document61334. The data is modulated by discrete frequency changes ofthe carrier frequency. The S-FSK method is used in smart metering in smart grids. At a few kilobits per second, the data rate is not as high as that achievable with Orthogonal Frequency Division Multiplex( OFDM), but it is sufficient for transmitting meter readings from smart meters. It is more robust than Orthogonal Frequency Division Multiplex (OFDM) and its implementation is cheaper. S-FSK is used in powerline transmission in the Cenelec bands up to 145 kHz.