Rate 16/17 (0,5) modulation code apparatus and method for partial response magnetic recording channels

Apparatus for decoding a codeword to provide a dataword representing binary data, the apparatus comprising:

• a storage circuit, coupled to an input stream to receive the codeword, which stores the codeword as N symbols;
• a processor, coupled to the storage circuit, which provides a set of pivot bits and preserved bits from the N symbols of the codeword and determines, from the set of pivot bits, whether the dataword includes a code violation, the set of pivot bits identifying a type and position of any code violation in the dataword, each code violation corresponding to a given bit sequence within the dataword;
• and
• a decoder circuit which forms the dataword from the preserved bits and the given bit sequence of each code violation in accordance with the set of pivot bits,
• wherein the decoder circuit decodes by reconstructing, as necessary, any code violation in the dataword as the given bit sequence having the type and at the position as defined by the set of pivot bits, and by assigning the preserved bits to respective locations in the dataword in accordance with the set of pivot bits.

A method of encoding a dataword as a codeword, the dataword corresponding to a sequence of M bits of binary data and the codeword having N symbols, M and N are integers and N is greater than M, the method comprising the steps of:

• (a) dividing the dataword into first and second bit strings and inserting a pivot bit therebetween;
• (b) determining whether each of the first and second bit strings contains at least one code violation, each code violation corresponding to a given bit sequence;
• and
• (c) correcting, as necessary, any code violation in the first and second bit strings by:
• (c1) defining values for one or more bits in each of the first and second bit strings as additional pivot bits, the additional pivot bits identifying a type and a position of the code violation;
• (c2) preserving values for bits not included in the given bit sequence corresponding to the code violation;
• and
• (c3) assigning values, as necessary, for one or more bits of the given bit sequence.

A method of decoding a codeword to provide a dataword, the dataword corresponding to a sequence of M bits of binary data and the codeword having N symbols, M and N are integer and N is greater than M, the method comprising the steps of:

• a) providing a set of pivot bits and a set of preserved bits from the N symbols of the codeword;
• b) determining, from the set of pivot bits, whether the dataword includes a code violation, the set of pivot bits identifying a type and position of any code violation, each code violation corresponding to a given bit sequence within the sequence of M bits;
• and
• c) forming the dataword from the preserved bits and the given bit sequence of each code violation in accordance with the set of pivot bits.

An integrated circuit including an encoding apparatus for providing a codeword from a dataword of binary data for encoding of the binary data on a magnetic media, comprising:

• memory means, coupled to an input stream for storing the dataword as first and second bit strings;
• processing means, coupled to the storage circuit, for determining whether each of the first and second bit strings contains at least one code violation, each code violation corresponding to a given bit sequence, the processing means identifying a type and a position of the code violation;
• encoding means, coupled to an input stream to receive the dataword, for encoding the dataword into the codeword, the encoding means inserting a pivot bit between the first and second strings,
• wherein the encoding means encodes by correcting, as necessary, any code violation in the first and second bit strings by 1) setting the inserted pivot bit to a first value, 2) defining values for one or more bits in each of the first and second bit strings as additional pivot bits, the additional pivot bits identifying the type and the position of the code violation, 3) preserving values for bits not included in the given bit sequence corresponding to the code violation, and 4) assigning values, as necessary, for one or more bits of the given bit sequence.

An integrated circuit including a decoding apparatus for decoding a codeword to provide a dataword representing binary data, the apparatus comprising:

• storage means, coupled to an input stream to receive the codeword, for storing the codeword as N symbols;
• processing means, coupled to the storage circuit, for providing a set of pivot bits and preserved bits from the N symbols of the codeword and determining, from the set of pivot bits, whether the dataword includes a code violation, the set of pivot bits identifying a type and position of any code violation in the dataword, each code violation corresponding to a given bit sequence within the dataword;
• and
• decoding means for forming the dataword from the preserved bits and the given bit sequence of each code violation in accordance with the set of pivot bits.
• wherein the decoding means decodes by reconstructing, as necessary, any code violation in the dataword as the given bit sequence having the type and at the position as defined by the set of pivot bits, and by assigning the preserved bits to respective locations in the dataword in accordance with the set of pivot bits.