Information recording/reproducing method and apparatus using EPRML connection processing system

Abstract

An information recording/reproducing apparatus includes first and second data demodulators having different data discriminating capabilities. The first data demodulator has a lower data discriminating capability and the second data demodulator has a higher data discriminating capability. When the reliability of reliability information for demodulation data generated by the first data demodulator, the second data demodulator is operated so that demodulation data generated by the first data demodulator is replaced by demodulation data generated by the second data demodulator during a period of time when the reliability of the reliability information is deteriorated.

1 . An information recording/reproducing method in an information recording/reproducing apparatus including a plurality of data demodulators which perform the data demodulation of an input signal, the method comprising: 
 a step of generating operation control information from at least one of reliability information for error information and/or demodulation data generated by a first data demodulator which is one of said plurality of data demodulators; and    a step of controlling the operation of a second data demodulator on the basis of said operation control information, said second data demodulator being one of said plurality of data demodulators other than said first data demodulator.    
     
     
         2 . An information recording/reproducing method according to    claim 1   , wherein the step of generating said operation control information includes a step of generating said operation control information on the basis of a likelihood difference at the time of data demodulation.  
     
     
         3 . An information recording/reproducing method according to    claim 1   , wherein the step of generating said operation control information includes a step of generating said operation control information on the basis of a plurality of survival paths which exist in a predetermined time.  
     
     
         4 . An information recording/reproducing method according to    claim 1   , wherein the step of generating said operation control information includes a step of generating said operation control information on the basis of a predetermined value of the run length of said demodulation data.  
     
     
         5 . An information recording/reproducing method according to    claim 1   , wherein the step of generating said operation control information includes a step of generating said operation control information on the basis of whether or not the result of code demodulation performed on the basis of said demodulation data matches with a predetermined code.  
     
     
         6 . An information recording/reproducing method according to    claim 1   , further comprising a step of replacing demodulation data of said first data demodulator by demodulation data of said second data demodulator on the basis of said operation control information.  
     
     
         7 . An information recording/reproducing method according to    claim 1   , further comprising a step of replacing demodulation data of said first data demodulator by demodulation data of said second data demodulator for a data decision period from the instant of time of generation of a plurality of survival paths of said first data demodulator to an instant of time when one survival path is selected again, the replacement being performed on the basis of the reliability information of demodulation data generated in said data decision period.  
     
     
         8 . An information recording/reproducing method according to    claim 1   , wherein the step of controlling the operation of said second data demodulator includes a step of setting an initial state of said second data demodulator on the basis of said operation control information.  
     
     
         9 . An information recording/reproducing method according to    claim 1   , wherein the step of controlling the operation of said second data demodulator includes a step of setting an initial state of said second data demodulator by use of demodulation data generated by said first data demodulator before the generation of said reliability information.  
     
     
         10 . An information recording/reproducing method according to    claim 1   , further comprising a step of converting said input signal into a signal adapted for data demodulation by said second data demodulator.  
     
     
         11 . An information recording/reproducing method in an information recording/reproducing apparatus including a plurality of data demodulators which have different data discriminating capabilities for an input signal, the method comprising: 
 a step of generating operation control information from at least one of reliability information for error information and/or demodulation data generated by a first data demodulator of said plurality of data demodulators which has a lower data discriminating capability; and    a step of controlling the operation of a second data demodulator on the basis of said operation control information, said second data demodulator being one of said plurality of data demodulators which has a higher data discriminating capability.    
     
     
         12 . An information recording/reproducing method according to    claim 11   , wherein the step of generating said operation control information includes a step of generating said operation control information on the basis of a likelihood difference at the time of data demodulation.  
     
     
         13 . An information recording/reproducing method according to    claim 11   , wherein the step of generating said operation control information includes a step of generating said operation control information on the basis of a plurality of survival paths which exist in a predetermined time.  
     
     
         14 . An information recording/reproducing method according to    claim 11   , wherein the step of generating said operation control information includes a step of generating said operation control information on the basis of a predetermined value of the run length of said demodulation data.  
     
     
         15 . An information recording/reproducing method according to    claim 11   , wherein the step of generating said operation control information includes a step of generating said operation control information on the basis of whether or not the result of code demodulation performed on the basis of said demodulation data matches with a predetermined code.  
     
     
         16 . An information recording/reproducing method according to    claim 11   , further comprising a step of replacing demodulation data of said first data demodulator by demodulation data of said second data demodulator on the basis of said operation control information.  
     
     
         17 . An information recording/reproducing method according to    claim 11   , further comprising a step of replacing demodulation data of said first data demodulator by demodulation data of said second data demodulator for a data decision period from the instant of time of generation of a plurality of survival paths of said first data demodulator to an instant of time when one survival path is selected again, the replacement being performed on the basis of the reliability information of demodulation data generated in said data decision period.  
     
     
         18 . An information recording/reproducing method according to    claim 11   , wherein the step of controlling the operation of said second data demodulator includes a step of setting an initial state of said second data demodulator on the basis of said operation control information.  
     
     
         19 . An information recording/reproducing method according to    claim 11   , wherein the step of controlling the operation of said second data demodulator includes a step of setting an initial state of said second data demodulator by use of demodulation data generated by said first data demodulator before the generation of said reliability information.  
     
     
         20 . An information recording/reproducing method according to    claim 11   , further comprising a step of converting said input signal into a signal adapted for data demodulation by said second data demodulator.  
     
     
         21 . An information recording/reproducing method in an information recording/reproducing apparatus including a plurality of data demodulators which perform the data demodulation of an input signal, the method comprising: 
 a step of generating first demodulation data and reliability information of said first demodulation data by a data demodulator in a first stage of said plurality of data demodulators;    a step of supplying said first demodulation data and said reliability information of said first demodulation data to the data demodulators in the next stage;    a step of controlling the operations of the data demodulators in said next stage on the basis of control information having different thresholds for said reliability information of said first demodulation data; and    a step of selecting second demodulation data from the data demodulators in said next stage.    
     
     
         22 . An information recording/reproducing method according to    claim 21   , wherein the step of generating said reliability information includes a step of generating said reliability information on the basis of a likelihood difference at the time of data demodulation.  
     
     
         23 . An information recording/reproducing method in an information recording/reproducing apparatus including a plurality of data demodulators which perform the data demodulation of an input signal, the method comprising: 
 a step of supplying said input signal to said plurality of data demodulators, said plurality of data demodulators having different data discriminating capabilities;    a step of deciding a demodulation performance from reliability information for demodulation data generated by a first data demodulator which is one of said plurality of data demodulators;    a step of controlling the operations of the others of said plurality of data demodulators on the basis of the result of decision; and    a step of selecting outputs of said plurality of data demodulators on the basis of said result of decision.    
     
     
         24 . An information recording/reproducing method according to    claim 23   , wherein said reliability information is generated on the basis of a likelihood difference at the time of data demodulation.  
     
     
         25 . An information recording/reproducing apparatus comprising: 
 a plurality of data demodulators each of which performs the data demodulation of an input signal;    means for generating operation control information from at least one of reliability information for error information and/or demodulation data generated by a first data demodulator which is any one of said plurality of data demodulators; and    means for controlling the operation of a second data demodulator on the basis of said operation control information, said second data demodulator being one of said plurality of data demodulators other than said first data demodulator.    
     
     
         26 . An information recording/reproducing apparatus according to    claim 25   , wherein the means for generating said operation control information includes means for generating said operation control information on the basis of a likelihood difference at the time of data demodulation.  
     
     
         27 . An information recording/reproducing apparatus according to    claim 25   , wherein the means for generating said operation control information includes means for generating said operation control information on the basis of a plurality of survival paths which exist in a predetermined time.  
     
     
         28 . An information recording/reproducing apparatus according to    claim 25   , wherein the means for generating said operation control information includes means for generating said operation control information on the basis of a predetermined value of the run length of said demodulation data.  
     
     
         29 . An information recording/reproducing apparatus according to    claim 25   , wherein the means for generating said operation control information includes means for generating said operation control information on the basis of whether or not the result of code demodulation performed on the basis of said demodulation data matches with a predetermined code.  
     
     
         30 . An information recording/reproducing apparatus according to    claim 25   , further comprising means for replacing demodulation data of said first data demodulator by demodulation data of said second data demodulator on the basis of said operation control information.  
     
     
         31 . An information recording/reproducing apparatus according to    claim 25   , further comprising means for replacing demodulation data of said first data demodulator by demodulation data of said second data demodulator for a data decision period from the instant of time of generation of a plurality of survival paths of said first data demodulator to an instant of time when one survival path is selected again, the replacement being performed on the basis of the reliability information of demodulation data generated in said data decision period.  
     
     
         32 . An information recording/reproducing apparatus according to    claim 25   , wherein the means for controlling the operation of said second data demodulator includes means for setting an initial state of said second data demodulator on the basis of said operation control information.  
     
     
         33 . An information recording/reproducing apparatus according to    claim 25   , wherein the means for controlling the operation of said second data demodulator includes means for setting an initial state of said second data demodulator by use of demodulation data generated by said first data demodulator before the generation of said reliability information.  
     
     
         34 . An information recording/reproducing apparatus according to    claim 25   , further comprising means for controlling from the exterior a decision range of the reliability information of the demodulation data generated by said first data demodulator.  
     
     
         35 . An information recording/reproducing apparatus according to    claim 25   , wherein the means for controlling said decision range from the exterior includes a register for setting said decision range.  
     
     
         36 . An information recording/reproducing apparatus according to    claim 25   , further comprising means for converting said input signal into a signal adapted for data demodulation by said second data demodulator.  
     
     
         37 . An information recording/reproducing apparatus according to    claim 25   , wherein the combination of said first and second data demodulators includes any combination of a PRML data demodulator, an EPRML data demodulator, an EEPRML data demodulator and a TRELLIS data demodulator.  
     
     
         38 . An information recording/reproducing apparatus comprising: 
 a plurality of data demodulators which perform the data demodulation of an input signal and have different data discriminating capabilities;    means for generating operation control information from at least one of reliability information for error information and/or demodulation data generated by a first data demodulator of said plurality of data demodulators which has a lower data discriminating capability; and    means for controlling the operation of a second data demodulator on the basis of said operation control information, said second data demodulator being one of said plurality of data demodulators which has a data discriminating capability higher than that of said first data demodulator.    
     
     
         39 . An information recording/reproducing apparatus according to    claim 38   , wherein the means for generating said operation control information includes means for generating said operation control information on the basis of a likelihood difference at the time of data demodulation.  
     
     
         40 . An information recording/reproducing apparatus according to    claim 38   , wherein the means for generating said operation control information includes means for generating said operation control information on the basis of a plurality of survival paths which exist in a predetermined time.  
     
     
         41 . An information recording/reproducing apparatus according to    claim 38   , wherein the means for generating said operation control information includes means for generating said operation control information on the basis of a predetermined value of the run length of said demodulation data.  
     
     
         42 . An information recording/reproducing apparatus according to    claim 38   , wherein the means for generating said operation control information includes means for generating said operation control information on the basis of whether or not the result of code demodulation performed on the basis of said demodulation data matches with a predetermined code.  
     
     
         43 . An information recording/reproducing apparatus according to    claim 38   , further comprising means for replacing demodulation data of said first data demodulator by demodulation data of said second data demodulator on the basis of said operation control information.  
     
     
         44 . An information recording/reproducing apparatus according to    claim 38   , further comprising means for replacing demodulation data of said first data demodulator by demodulation data of said second data demodulator for a data decision period from the instant of time of generation of a plurality of survival paths of said first data demodulator to an instant of time when one survival path is selected again, the replacement being performed on the basis of the reliability information of demodulation data generated in said data decision period.  
     
     
         45 . An information recording/reproducing apparatus according to    claim 38   , wherein the means for controlling the operation of said second data demodulator includes means for setting an initial state of said second data demodulator on the basis of said operation control information.  
     
     
         46 . An information recording/reproducing apparatus according to    claim 38   , wherein the means for controlling the operation of said second data demodulator includes means for setting an initial state of said second data demodulator by use of demodulation data generated by said first data demodulator before the generation of said reliability information.  
     
     
         47 . An information recording/reproducing apparatus according to    claim 38   , further comprising means for controlling from the exterior a decision range of the reliability information of the demodulation data generated by said first data demodulator.  
     
     
         48 . An information recording/reproducing apparatus according to    claim 38   , wherein the means for controlling said decision range from the exterior includes a register for setting said decision range.  
     
     
         49 . An information recording/reproducing apparatus according to    claim 38   , further comprising means for converting said input signal into a signal adapted for data demodulation by said second data demodulator.  
     
     
         50 . An information recording/reproducing apparatus according to    claim 38   , wherein the combination of said first and second data demodulators includes any combination of a PRML data demodulator, an EPRML data demodulator, an EEPRML data demodulator and a TRELLIS data demodulator.  
     
     
         51 . An information recording/reproducing apparatus comprising: 
 first and second data demodulators which perform the data demodulation of an input signal with different data discriminating capabilities, respectively, the data discriminating capability of said first data demodulator being lower than that of said second data demodulator;    a control circuit connected between said first and second data demodulators for controlling the operation of said second data demodulator on the basis of reliability information of error information and/or demodulation data generated by said first data demodulator; and    a circuit for synthesizing demodulation data of said first and second data demodulators.    
     
     
         52 . An information recording/reproducing apparatus according to    claim 51   , wherein said control circuit includes a circuit for generating a control signal on the basis of a likelihood difference at the time of data demodulation.  
     
     
         53 . An information recording/reproducing apparatus according to    claim 51   , wherein said control circuit includes a circuit for generating a control signal on the basis of a plurality of survival paths which exist in a predetermined time.  
     
     
         54 . An information recording/reproducing apparatus according to    claim 51   , wherein said control circuit includes a circuit for generating a control signal on the basis of a predetermined value of the run length of said demodulation data.  
     
     
         55 . An information recording/reproducing apparatus according to    claim 51   , further comprising a mis-code detecting circuit between said first data demodulator and said control circuit, said control circuit including a circuit for generating a control signal on the basis of an output of said mis-code detecting circuit.  
     
     
         56 . An information recording/reproducing apparatus according to    claim 51   , wherein said circuit for synthesizing the demodulation data includes a multiplexer for synthesizing the demodulation data of said first and second data modulators in accordance with a control signal from said control circuit.  
     
     
         57 . An information recording/reproducing apparatus according to    claim 51   , wherein said control circuit includes a circuit for determining a data decision period from the instant of time of generation of a plurality of survival paths of said first data demodulator to an instant of time when one survival path is selected again, and a circuit for replacing demodulation data of said first data demodulator by demodulation data of said second data demodulator on the basis of the reliability information of demodulation data generated in said data decision period.  
     
     
         58 . An information recording/reproducing apparatus according to    claim 51   , wherein said control circuit includes a circuit for setting an initial state of said second data demodulator on the basis of said reliability information of the error information and/or the demodulation data.  
     
     
         59 . An information recording/reproducing apparatus according to    claim 51   , wherein said control circuit includes a circuit for setting an initial state of said second data demodulator by use of demodulation data generated by said first data demodulator before the generation of said reliability information.  
     
     
         60 . An information recording/reproducing apparatus according to    claim 51   , further comprising a register connected to said control circuit for setting a decision range of said reliability information of the demodulation data.  
     
     
         61 . An information recording/reproducing apparatus according to    claim 51   , further comprising a signal conversion circuit for converting said input signal into a signal adapted for said second data demodulator.  
     
     
         62 . An information recording/reproducing apparatus according to    claim 51   , further comprising a delay circuit for delaying said input signal to supply the delayed input signal to said second data demodulator.  
     
     
         63 . An information recording/reproducing apparatus according to    claim 51   , further comprising a delay circuit for delaying demodulation data of said first demodulator.  
     
     
         64 . An information recording/reproducing apparatus according to    claim 51   , wherein the combination of said first and second data demodulators includes any combination of a PRML data demodulator, an EPRML data demodulator, an EEPRML data demodulator and a TRELLIS data demodulator.  
     
     
         65 . An information recording/reproducing apparatus comprising: 
 a first data demodulator for receiving an input signal to generate demodulation data and reliability information of the demodulation data;    a plurality of second data demodulators connected to the rear stage of said first data demodulator for receiving said demodulation data and said reliability information of the demodulation data; and    a circuit for synthesizing demodulation data of said plurality of second data demodulators.    
     
     
         66 . An information recording/reproducing apparatus according to    claim 65   , wherein said plurality of second data demodulators include circuits for deciding said reliability information by different thresholds, respectively.  
     
     
         67 . An information recording/reproducing apparatus comprising: 
 a plurality of data demodulators which have different data discriminating capabilities and receive the same input signal;    a first multiplexer connected to said plurality of data demodulators for selecting reliability information for demodulation data respectively generated by said data demodulators;    a decision circuit connected to said first multiplexer for deciding the demodulation performance of a selected data demodulator; and    a second multiplexer connected to said plurality of data demodulators for selecting demodulation data from said plurality of data demodulators in accordance with a signal from said decision circuit.    
     
     
         68 . An information recording/reproducing apparatus according to    claim 67   , wherein said decision circuit includes a circuit for deciding the demodulation performance on the basis of a likelihood difference at the time of data demodulation.  
     
     
         69 . An information recording/reproducing apparatus comprising: 
 a first data demodulator which performs the data demodulation of an input signal;    a second data demodulator which has a data discriminating capability higher than that of said first data demodulator and performs the data demodulation of said input signal;    a control circuit for deciding a reliability for demodulation data generated by said first data demodulator to operate said second data demodulator having the higher data discriminating capability when said reliability is deteriorated; and    a circuit for replacing demodulation data of said first data demodulator by demodulation data of said second data demodulator during a period of time when said reliability is deteriorated.    
     
     
         70 . An information recording/reproducing apparatus according to    claim 69   , wherein said control circuit includes a circuit for deciding said reliability on the basis of a likelihood difference.  
     
     
         71 . An information recording/reproducing apparatus according to    claim 69   , wherein said control circuit includes a circuit for deciding said reliability on the basis of a run length of the demodulation data.  
     
     
         72 . An information recording/reproducing apparatus according to    claim 69   , wherein said control circuit includes a circuit for deciding said reliability on the basis of whether or not the demodulation data exists in a predetermined code.  
     
     
         73 . An information recording/reproducing apparatus according to    claim 69   , wherein said control circuit includes a circuit for deciding said reliability on the basis of error information of the demodulation data.  
     
     
         74 . An information recording/reproducing apparatus according to    claim 69   , wherein said first data demodulator has a power consumption smaller than that of said second data demodulator.  
     
     
         75 . An information recording/reproducing apparatus comprising: 
 a first data demodulator which performs the data demodulation of an input signal;    a second data demodulator which performs the data demodulation of said input signal with a power consumption larger than that of said first data demodulator;    a control circuit for deciding a reliability for demodulation data generated by said first data demodulator to operate said second data demodulator when said reliability is deteriorated; and    a circuit for replacing demodulation data of said first data demodulator by demodulation data of said second data demodulator during a period of time when said reliability is deteriorated.    
     
     
         76 . An information recording/reproducing apparatus according to    claim 75   , wherein said control circuit includes a circuit for deciding said reliability on the basis of a likelihood difference.  
     
     
         77 . An information recording/reproducing apparatus according to    claim 75   , wherein said control circuit includes a circuit for deciding said reliability on the basis of a run length of the demodulation data.  
     
     
         78 . An information recording/reproducing apparatus according to    claim 75   , wherein said control circuit includes a circuit for deciding said reliability on the basis of whether or not the demodulation data exists in a predetermined code.  
     
     
         79 . An information recording/reproducing apparatus according to    claim 75   , wherein said control circuit includes a circuit for deciding said reliability on the basis of error information of the demodulation data.  
     
     
         80 . An information recording/reproducing apparatus according to    claim 75   , where said second data demodulator has a data discriminating capability higher than that of said first data demodulator.