Signal processing method and apparatus and disk device using the method and apparatus

A data signal processing apparatus comprising:

• a data discriminator which receives an input data string;
• a post-coder which is connected to receive a bit string including data and data sync signals from said data discriminator and performs a predetermined post-code processing on said bit string;
• a decoder which is connected to receive the post-code processed bit string output from said post-coder, and decodes the post-code processed bit string to output reproduced data;
• and
• a data sync signal detector which is connected to receive said post-code processed bit string and matches a pattern of said post-code processed bit string against a predetermined sync pattern to detect each of said data sync signals, said decoder performing the decode operation upon detection of each data sync signal, wherein a total number of bits of the pattern used for matching in said data sync signal detector is 18 bits or less, and assuming that Be is the ratio of occurrence of an error event to the total number of output bits from said data discriminator and Se is the ratio of occurrence of the data sync signal detection error to the number of requests for data sync signal detection, Se can be approximated by the characteristic expressed by Equation 1, 2 or 3 below in the range of Be not more than 0.1,
• Se=7Be1.20 Eq. 1
• Se=12Be1.42 Eq. 2
• Se=20Be1.64 Eq. 3.

A data signal processing apparatus comprising:

• a data discriminator which receives an input data string;
• a post-coder which is connected to receive a bit string including data and data sync signals from said data discriminator and performs a predetermined post-code processing on said bit string;
• a decoder which is connected to receive the post-code processed bit string output from said post-coder, and decodes the post-code processed bit string to output reproduced data;
• and
• a data sync signal detector which is connected to receive said post-code processed bit string and matches a pattern of said post-code processed bit string against a predetermined sync pattern to detect each of said data sync signals, said decoder performing the decode operation upon detection of each data sync signal, wherein a total number of bits of the pattern used for matching in said data sync signal detector is 36 bits or less, and assuming that Be is the ratio of occurrence of an error event to the total number of output bits from said data discriminator and Se is the ratio of occurrence of the data sync signal detection error to the number of requests for data sync signal detection, Se can be approximated by the characteristic expressed by Equation 1 or 2 below in the range of Be not more than 0.1,
• Se=90Be2.51 Eq. 1
• Se=160Be3.15 Eq. 2.

A magnetic disk device comprising:

• a magnetic disk;
• a magnetic head which records and reproduces data on said magnetic disk;
• and
• a signal processing apparatus which encodes said data to be recorded on said magnetic disk through said magnetic head and decodes said data reproduced from said magnetic disk, wherein said signal processing apparatus includes;
• a data discriminator which receives a data bit string read from said magnetic head;
• a post-coder which is connected to receive a bit string containing data and data sync signals output from said data discriminator and performs a predetermined post-code processing on said received bit string;
• a decoder which is connected to receive a post-coded bit string output from said post-coder, performs a predetermined decoding on said bit string and outputs reproduced data;
• a (1+D) processing unit which is connected to receive said post-coded bit string output from said post-coder and performs (1+D) processing on said received bit string;
• and
• a data sync signal detector which is connected to receive the (1+D) processed bit string from said (1+D) processing unit and detects said data sync signal;
• said decoder performing the decode operation upon detection of the data sync signal by said data sync signal detector;
• wherein said data sync signal detector includes a separator which separates the (1+D) processed bit string into a bit string of odd numbered bits and a bit string of even numbered bits and outputs each of the bit strings separated into a group of bit strings or two or more groups of bit strings with or without a string of 1 or more bits of an arbitrary bit pattern interposed therebetween, a matching unit, provided one for each group, which matches a pattern of the bit string in each group against a corresponding predetermined sync pattern to detect a match therebetween, and a decision unit which indicates detection of a data sync signal to said decoder when a number of groups that coincide with respective sync patterns is equal to or larger than a predetermined threshold value.

A data signal processing apparatus comprising:

• a data discriminator which receives an input bit string;
• a post-coder which is connected to receive a bit string including data and data sync signals output from said data discriminator and performs a predetermined post-code processing on said bit string;
• a decoder which is connected to receive the post-code processed bit string output from said post-coder, and decodes the post-code processed bit string to output reproduced data;
• an error detection/correction unit which is connected to receive the post-code processed bit string output from said post-coder and performs an error detection/correction on said bit string;
• and
• a data sync signal detector which is connected to sequentially receive the error-detected/corrected bit string from said error detection/correction unit to detect the data sync signals, said decoder performing the decode operation upon detection of each data sync signal by said data sync signal detector;
• wherein said error detection/correction unit includes a separator which separates the post-coded bit string into at least one bit string and outputs each bit string in a group of bit string or two or more groups of bit string, and an error detection/correction unit, provided for each group, for detecting and correcting an error of the bit string of each group, and
• wherein said data sync signal detector includes a matching unit, provided one for each group, which matches a pattern of the bit string of each group after error detection/correction against a corresponding predetermined sync pattern to detect a coincidence therebetween, and a decision unit which indicates detection of a data sync signal to said decoder when a number of groups that coincide with respective sync patterns is equal to or larger than a predetermined threshold value.

A data sync signal detection apparatus comprising:

• a separator which receives a bit string containing data and data sync signals output from a data discriminator, separates said bit string into one group of bit string or a plurality of groups of bit string, and outputs said bit string in said one or plurality of groups of bit string;
• an error detection/correction unit, provided for each of said groups, which detects and corrects an error in each group;
• and
• a sync signal detector which detects the data sync signals by matching said discriminated and error corrected bit string of said each group against a corresponding predetermined data sync pattern.

A data sync signal detection method comprising the steps of:

• receiving a bit string containing data and data sync signals output from a data discriminator and performing a predetermined post-code processing on said bit string;
• performing (1+D) processing on the post-coded bit string;
• detecting each of said data sync signal from said (1+D) processed bit string;
• and
• performing a predetermined decode operation on said post-coded bit string upon detection of said each data sync signal;
• wherein said data sync signal detection step includes the substeps of separating said (1+D) processed bit string into a bit string of odd numbered bits and a bit string of even numbered bits, outputting each of said bit strings separated into one bit-string group or two or more bit-string groups divided with or without an arbitrary pattern of a bit string of at least one bit interposed therebetween, matching a bit string pattern of each group against a corresponding predetermined sync pattern thereby to decide whether they coincide with each other, and in the case where a number of groups coinciding with said predetermined sync pattern is not less than a predetermined threshold value, indicating the detection of said data sync signal to said predetermined decode operation.

A data sync signal detection apparatus comprising:

• a (I+D) processing unit which receives a post-coded bit string containing data and data sync signals output from a data discriminator and performs (I+D) processing on said bit string;
• and
• a data sync signal detector which detects said data sync signals from the (1+D) processed bit string output from said (1+D) processing unit;
• wherein said data sync signal detector includes a separator which separates the (1+D) processed bit string into a bit string of odd numbered bits and a bit string of even numbered bits and outputs each of the bit strings separated into a group of bit strings or two or more groups of bit strings divided with or without a string of 1 or more bits of an arbitrary bit pattern interposed therebetween, a matching unit, provided one for each group, which matches a pattern of the bit string in each group against a corresponding predetermined sync pattern to detect a coincidence therebetween, and a decision unit which indicates detection of a data sync signal to a decoder when a number of groups that coincide with respective sync patterns is equal to or larger than a predetermined threshold value.

A data sync signal detection apparatus, comprising:

• a separator which receives a bit string containing data and data sync signals output from a data discriminator, separates said bit string into one group of bit string or a plurality of groups of bit string, and outputs said bit string in said one or plurality of groups of bit string;
• an error detection/correction unit, provided for each of said groups, which detects and corrects an error in each group;
• and
• a sync signal detector which detects the data sync signals by matching said discriminated and error corrected bit string of said each group against a corresponding predetermined data sync pattern,
• wherein said data discriminator includes a Maximum Likelihood decoder.

A computer software product including a computer readable medium, said medium having stored thereon:

• code means for performing (1+D) processing on a bit string obtained by performing predetermined post-code processing on a bit string containing data and data sync signals output from a data discriminator;
• code means for detecting said data sync signal from said (1+D) processed bit string;
• and
• data sync signal detection code means for separating said (1+D) processed bit string into a bit string of odd numbered bits and a bit string of even numbered bits, and outputting each of said bit strings separated into one bit string group or at least two bit string groups divided with or without an arbitrary pattern of bit string of at least one bit interposed therebetween, matching a pattern of the bit string of each group against a predetermined sync pattern thereby to decide whether they are coincident or not, and upon coincidence, detecting a data sync signal.

A data sync signal detection method comprising the steps of:

• receiving a bit string containing data and data sync signals output from a data discriminator, outputting said bit string separated into one group or a plurality of groups of a bit string;
• performing an error detection and error correction processing on each group;
• and
• matching a pattern of said discriminated and error corrected bit string of each group against a predetermined data sync pattern thereby to detect a data sync signal.

A computer software product including a computer readable medium, said medium having stored thereon:

• code means for receiving and separating a bit string containing data and data sync signals output from a data discriminator into one group or a plurality of groups of a bit string;
• code means for performing an error detection and error correction on each of said groups;
• and
• code means for matching the discriminated and error corrected bit string of each group against a corresponding predetermined data sync pattern thereby to detect a data sync signal.

A magnetic disk device comprising:

• a magnetic disk;
• a magnetic head which records and reproduces data on said magnetic disk;
• a signal processing apparatus which encodes said data to be recorded on said magnetic disk and decodes said data reproduced from said magnetic disk, wherein said signal processing apparatus includes:
• a data discriminator which receives a data bit string read from said magnetic head;
• a post-coder which is connected to receive a bit string including data and data sync signals outputted from said data discriminator and performs predetermined post-code processing on said received bit string;
• a decoder which is connected to receive a post-coded bit string output from said post-coder, decodes said post-code processed bit string to output reproduced data;
• an error correction/detection unit which is connected to receive said post-coded bit string and performs an error detection/correction on said bit string;
• and
• a data sync signal detector which is connected to receive said error detected/corrected bit string from said error detection/correction unit to detect said data sync signals, said decoder performing the decode operation upon detection of each data sync signal by said data sync signal detector,
• wherein said error detection/correction unit includes a separator which separates the post-coded bit string into at least one bit string and outputs each bit string in a group of bit string or two or more groups of bit string, an error detection/correction part provided for each group of bit string which error detects and corrects the bit string of each group, wherein said data sync signal detector includes a matching unit, provided one for each group, which matches a pattern of the bit string of each group after error detection/correction against a corresponding predetermined sync pattern to detect a coincidence therebetween, and a decision unit which indicates detection of a data sync signal to said decoder when a number of groups that coincides with respective sync patterns is equal to or larger than a predetermined threshold value.

A data sync signal detection apparatus comprising:

• a separator which receives and separates a bit string of codes including data and data sync signals received from a data discriminator into a bit string of odd numbered bits and a bit string of even numbered bits and outputs each of said bit string of odd numbered bits and bit string of even numbered bits in a single group of bit string or in two or more groups of bit string with or without a bit string of at least one bit of an arbitrary pattern interposed between said groups;
• an error detection/correction unit which performs an error detection/correction on each group of bit string;
• and
• matching units, one for each group of bit string, which matches a pattern of each group of bit string after error correction/detection against a corresponding predetermined sync pattern to determine a coincidence therebetween so as to detect each data sync signal.

A computer software product including a computer readable medium, said medium having stored thereon:

• a code means for separating a bit string of codes including data and data sync signals received from a data discriminator into a bit string of odd numbered bits and a bit string of even numbered bits and outputting each bit string in a single group of bit string or in two or more groups of bit string divided with or without a string of at least one bit of an arbitrary pattern interposed therebetween;
• a code means for subjecting each group of bit string to error detection and correction;
• and
• a code means for matching a pattern of each group of bit string after error detection/correction against a corresponding predetermined sync pattern for determining a matching therebetween.