Editing Frequency-shift keying (section)

===Continuous-phase frequency-shift keying===
{{Main | continuous-phase frequency-shift keying}}

In principle FSK can be implemented by using completely independent free-running oscillators, and switching between them at the beginning of each symbol period.
In general, independent oscillators will not be at the same phase and therefore the same amplitude at the switch-over instant,
causing sudden discontinuities in the transmitted signal.

In practice, many FSK transmitters use only a single oscillator, and the process of switching to a different frequency at the beginning of each symbol period preserves the phase.
The elimination of discontinuities in the phase (and therefore elimination of sudden changes in amplitude) reduces [[sideband]] power, reducing interference with neighboring channels.