INT 65 - Media Vision FM(Frequency Modulation) A method of encoding data as a series of magnetic flux reversals on disk or tape, commonly known as single-density recording. In frequency modulation, a series of clock pulses are written at regular intervals, with one data bit for each clock pulse. See also MFM, RLL..COM v4.1a+ - START BACKGROUND FM(Frequency Modulation) A method of encoding data as a series of magnetic flux reversals on disk or tape, commonly known as single-density recording. In frequency modulation, a series of clock pulses are written at regular intervals, with one data bit for each clock pulse. See also MFM, RLL. SOUNDS SI = 8002h SeeAlso: SI=8003h