What Does Multiple Frequency-Shift Keying (MFSK) Mean?Multiple frequency-shift keying (MFSK) is a method of signal modulation that extends the radio teletype (RTTY) two-tone technique to multiple tones, producing fewer errors. MFSK signal modulation technique involves discrete audio tone bursts of different frequencies, which deliver digital data. This technique was originally used by British and other European government agencies during the mid-1900s.
MSFK is a variant of frequency-shift keying (FSK), which makes use of more than two frequencies to transmit digital data.
At the time of its invention, MSFK was referred to as Piccolo, which is a high-pitched musical instrument that sounds much like an MFSK signal over a radio receiver speaker.