Topic summary
MMFM
Extracted from the Wikipedia article Modified frequency modulation.
MMFM
MMFM (modified modified frequency modulation), also abbreviated M²FM or M2FM, is similar to MFM, but suppresses additional clock bits, producing a longer maximum run length (a (1,4) RLL code). In particular, a clock pulse is only inserted between a pair of adjacent 0-bits if the first bit of the pair did not have a clock pulse inserted before it. In the example below, clock bits that would have been present in MFM are noted in bold: