Optical recording disk capable of resynchronization in digital encoding and decoding

Abstract

In carrying out PWM-recording on optical disks, RESYNC BYTES including a bit compensation part, RESYNC detection part, and bit synchronization part are periodically inserted in the recorded data code stream. After encoding and at the time of decoding, RESYNC BYTES are detected by detection of the RESYNC detection part. The decoder is initialized by detecting the position of the bit synchronization part and decoding is performed satisfactorily free from error. With this configuration, even for synchronization bytes having a comparatively long portion of consecutive code values, bit resynchronization is enabled free from mis-detection caused by peak shift. Even with the recording and reproducing characteristics with an un-symmetrical unerased area of the mark and space parts, the RESYNC detection part is fixed to either mark or space and RESYNC BYTES with little influence on an unerased area can be realized.

What is claimed is:  
     
       1. An optical disk having a recording surface including first regions that represent first data and second regions that represent second data; 
       the first regions and the second regions together representing digital data carried by said disk and RESYNC BYTES present at a certain interval between groups of digital data on said disk;  
       the first regions and the second regions each having areas that represent the digital data as digital data that is encoded to satisfy a (d,k) conversion rule wherein d is a minimum number of first data and k is a maximum number of first data that separate a datum of the second data, and that represent the RESYNC BYES as bytes that each include a RESYNC detection part that violates the (dk) conversion rule, and a bit synchronization part that satisfies the (d,k) conversion rule.  
     
     
       2. An optical disk as claimed in  claim 1 , wherein the first regions include pits in the recording surface and the second regions do not include pits in the recording surface. 
     
     
       3. An optical disk as claimed in  claim 2 , 
       wherein one of the first data and the second data is a logical “0” and the other of the first data and the second data is a logical “1” ;  
       wherein the representing areas of the first regions and the second regions further represent the RESYNC BYTES as BYTES that each include a bit compensation part located at a head position in the RESYNC BYTE,  
       wherein the RESYNC detection part has a number N, of “0's” which separate “1's” that is N>k, and  
       wherein the bit synchronization part consists of at least a minimum of one “0” and a minimum of one “1”.  
     
     
       4. An optical disk as claimed in  claim 3 , wherein a “1” is separated by k+3 “0s” in the RESYNC detection part. 
     
     
       5. An optical disk as claimed in  claim 2 , wherein the areas of the first regions and the second regions represent the (d, k) encoded digital data and the RESYNC BYTE also as an NRZI encoded data stream. 
     
     
       6. An optical disk for recording data, comprising: 
         a recording surface including first regions for representing digital data that satisfy a  ( d, k )  conversion rule and second regions for representing RESYNC BYTE data including RESYNC BYTES, said second regions being periodically inserted in said first regions, wherein    
         each of said RESYNC BYTES includes a RESYNC detection part that violates said  ( d, k )  conversion rule and a bit synchronization part that satisfies said  ( d, k )  conversion rule,    
       
         said digital data and said RESYNC BYTE data being comprised of first type data and second type data, and  
       
         d and k of said  ( d, k )  conversion rule respectively indicate a minimum number and a maximum number of said first type data between two data of said second type data.   
     
     
       7. An optical disk according to  claim 6 , wherein said RESYNC detection part corresponds to a mark portion on said recording surface. 
     
     
       8. An optical disk according to  claim 6 , wherein one of said first type data and said second type data is a logical “ 0 ” and the other of said first type data and said second type data is a logical “ 1 ”. 
     
     
       9. A digital coding method for recording data on an optical disk, said method comprising the steps of: 
         modulating digital data encoded in accordance with a  ( d, k )  conversion rule for providing modulated data; and    
       
         adding RESYNC BYTE data including RESYNC BYTES in said modulated data,  
       
         each of said RESYNC BYTES comprising a RESYNC detection part which violates said  ( d, k )  conversion rule and a bit synchronization part which satisfies said  ( d, k )  conversion rule,    
       
         said digital data and said RESYNC BYTE data being comprised of first type data and second type data, and  
       
         d and k of said  ( d, k )  conversion rule respectively indicating a minimum number and a maximum number of said first type data between two data of said second type data.   
     
     
       10. A digital coding method according to  claim 9 , wherein one of said first type data and said second type data is a logical “ 0 ” and the other of said first type data and said second type data is a logical “ 1 ”. 
     
     
       11. A digital coding method according to  claim 9 , further comprising the step of encoding said modulated data and said RESYNC BYTE data according to an NRZI rule.