Double-attribute method of encoding and decoding magnetic data

A method of encoding and decoding digital data intended for storage on a magnetic disk medium, comprising:

• (a) providing a divider means which is operable to receive a binary source data sequence and divide it into a first divided data segment and a second divided data segment, wherein:
• (1) said binary source data sequence comprises a predetermined number of source data bits, and
• (2) said first divided data segment comprises a first predetermined number of divided data bits, and
• (3) said second divided data segment comprises a second predetermined number of divided data bits,
• (b) providing a mission-dependent modulation look-up table, wherein:
• (1) said mission-dependent modulation look-up table indicates a first modulation value corresponding to the binary value of said first divided data segment, and
• (2) said mission-dependent modulation look-up table indicates a second modulation value corresponding to the binary value of said second divided data segment,
• (c) providing a modulation means, comprising, in combination, a pulse width modulator and a pulse position modulator, wherein:
• (1) said pulse width modulator receives said first divided data segment and modulates the pulse width of said output signal according to said first modulation value indicated in the modulation look-up table corresponding to the binary value of said first divided data segment, said output signal having pulse width as a first attribute, and
• (2) said pulse position modulator receives said second divided data segment and modulates the pulse position of said output signal according to said second modulation value indicated in the modulation look-up table corresponding to the binary value of said second divided data segment, said output signal having pulse position as a second attribute,
• (d) providing a multiplexing means which is operable to receive said first attribute and said second attribute of the output signal from said modulation means, and add the attributes together to form a multiplexed encoded data symbol, wherein:
• (1) said multiplexing means generates said multiplexed encoded data symbol in response to said first attribute and said second attribute received in the form of said output signal from said modulation means.