Information storage medium, information recording apparatus, and information reproduction apparatus

Abstract

An information storage medium according to an embodiment of this invention has an area for storing predetermined data modulated according to the (d, k; m, n) modulation rule. The predetermined data includes at least one SYNC code in a predetermined recording unit, and the number of “1”s included in a predetermined number of a series of channel bits at an arbitrary position in the SYNC code is not more than a half the predetermined number.

1 . An information storage medium comprising: 
 a data area being configured to store predetermined data in predetermined recording units,    wherein a part of the predetermined data is modulated according to a (d, k; m, n) modulation rule.    the (d, k; m, n) modulation rule modulates m-bit source data into n-channel bit data, so that modulated channel bit patterns satisfy conditions that a minimum d pieces of 0s successively arranged and a maximum of k pieces of 0s successively arranged,    the predetermined data includes a plurality of SYNC codes in the predetermined recording units,    a number of 1s included in a predetermined number of a series of channel bits at an arbitrary position in the SYNC code is not more than a half the predetermined number,    each of the plurality of SYNC codes includes a fixed code and a variable code,    wherein the fixed code includes k or more sequences of 0s successively arranged and d+1 sequences of 0s successively arranged,    wherein the variable code is one of a first pattern (SY 0 ), a second pattern (SY 1 ), a third pattern (SY 2 ), and a fourth pattern (SY 3 ),    combinations of the variable codes of three successive SYNC codes in the predetermined recording units are different from one another, and    the SYNC code is comprised of 24 channel bits. SYNC frame data subsequent to the SYNC code is comprised of 1092 channel bits, four types of SYNC codes including the first pattern, the second pattern, the third pattern, and the fourth pattern, respectively, are defined, each of the predetermined recording units is called one sector, the first pattern is arranged in an initial position of said one sector, and the second pattern is arranged in a last position of said one sector.    
   
   
       2 . A medium according to  claim 1 , wherein all patterns contained in the SYNC code satisfy a condition that a number of 1s included in a series of N channel bits is not more than INT[N/(d+1)]
 where INT[X] is an integer value obtained by dropping digits after the decimal point of X, and    N is given by N={(d+1).times.INT[9/(d+1)]}+1.    
   
   
       3 . A medium according to  claim 1 , wherein nor less than 66% of patterns contained in the SYNC code satisfy a condition that a number of 1s included in a series of (N−1) channel bits is not more than INT[(N−1)/(d+1)]−1 
 where INT[X] is an integer value obtained by dropping digits after the decimal point of X, and    N is given by N={(d+1).times.INT[9/(d+1)]}+1.    
   
   
       4 . A medium according to  claim 1 , wherein the predetermined data stored in said information storage medium is modulated according to a (l, k; m, n) modulation rule, and 
 all patterns contained in the SYNC code satisfy a condition that a number of 1s included in a series of 9 channel bits is not more than 4.    
   
   
       5 . A medium according to  claim 1 , wherein the predetermined data stored in said information storage medium is modulated according to a (l, k; m, n) modulation rule, and 
 not less than 66% of patterns contained in the SYNC code satisfy a condition that a number of is included in a series of 8 channel bits is not more than 3.    
   
   
       6 . An information storage medium comprising: 
 a data area being configured to store predetermined data in predetermined recording units,    wherein a part of the predetermined data is modulated according to a (d, k; m, n) modulation rule,    the (d, k; m, n) modulation rule modulates m-bit source data into n-channel bit data, so that modulated channel bit patterns satisfy conditions that a minimum d pieces of 0s successively arranged and a maximum of k pieces of 0s successively arranged, and    the predetermined data includes a plurality of SYNC codes in the predetermined recording units.