United States Patent [19]
`Okada et al.
`
`[54] INFORMATION RECORDING
`REPRODUCING APPARATUS USING DATA
`CONVERSION TO PROVIDE FOR
`ACCURATE REPRODUCTION OF HIGH
`DENSITY RECORDING USING AN OPTICAL
`RECORDING MEDIUM
`Shinichi Okada; Kyota Funamoto,
`[75] Inventors:
`both of Tokorozawa, Japan
`[73] Assignee: Pioneer Electronic Corporation,
`Tokyo, Japan
`254,433
`Jun. 6, 1994
`
`Appl. No.:
`Filed:
`
`[21]
`[22]
`
`[63]
`
`Related U.S. Application Data
`Continuation of Ser. No. 914,528, Jul. 17, 1992, aban
`doned.
`Foreign Application Priority Data
`[30]
`Jan. 21, 1992 [JP]
`Japan .................................. 4-008605
`[51] Int. Cl* ................................................ G11B 7/00
`[52] U.S. Cl. ...................................... 369/59; 369/124;
`341/67
`[58] Field of Search ....................... 369/59, 58, 54, 53,
`369/42, 48, 124, 60; 341/50, 58, 59, 68, 88, 55;
`360/47, 48, 50, 49, 51, 67, 40, 39, 42
`References Cited
`U.S. PATENT DOCUMENTS
`4,484,176 11/1984 Fitzpatrick ............................ 341/59
`4,584,616 4/1986 Allen ..................................... 360/50
`4,833,471 5/1989 Tokuume et al. ..................... 341/67
`4,866,692 9/1989 Saito et al. ............................ 369/59
`Primary Examiner—Aristotelis Psitos
`Assistant Examiner—Muhammad N. Edun
`Attorney, Agent, or Firm—Sughrue, Mion, Zinn,
`Macpeak & Seas
`
`[56]
`
`|US005392270A
`[11] Patent Number:
`[45] Date of Patent:
`
`5,392,270
`Feb. 21, 1995
`
`ABSTRACT
`[57]
`Disclosed is an information recording/reproducing
`apparatus using an optical recording medium, which
`can reproduce information from a recording medium
`designed to have a high linear recording density, by a
`method of performing signal separation/extraction by
`one threshold level in a level detecting process at the
`time of information reproduction from an optical re
`cording medium with a high linear recording density.
`The information recording apparatus comprises a data
`converting means for perform data conversion on re
`cord information consisting of a digital signal in accor
`dance with a predetermined data conversion table in
`cluding a pattern for yielding a converted pattern con
`sisting of at least one “0” and an even number of consec
`utive “1” or a converted pattern having a section con
`sisting of “01010” and a section consisting of at least one
`“0” or an even number of consecutive “1”; a data modu
`lating means for inverting an initial output signal when
`bit information of data after the data conversion is “1”
`given that the initial output signal is “0”; and a record
`ing means for recording the output signal on an optical
`recording medium. The information reproducing appa
`ratus comprises a reading means for reading information
`from the optical recording medium to yield a repro
`duced signal; a level detecting means for detecting a
`level of the reproduced signal and outputting digital
`data; an error correcting means for, upon detection of a
`sequence of “01110” in a bit pattern of the digital data,
`correcting the sequence to a sequence of “01010” and
`outputting corrected data, and, upon detection of no
`error, outputting the digital data; and a data reverse
`converting means for performing reverse conversion on
`the output data of the error correcting means in accor
`dance with the data conversion table, yielding repro
`duced information.
`
`2 Claims, 4 Drawing Sheets
`
`
`
`5
`
`
`
`
`
`
`
`EQUALizer
`AMPLIFIER
`
`
`
`73-8
`
`12
`
`THRESHOLD
`
`ERROR Coºgecting
`circuit
`
`REPRODUCED
`INFORMATION
`
`LSI Corp. Exhibit 1007
`Page 1
`
`

`

`U.S. Patent
`
`Feb. 21, 1995
`
`Sheet 1 of 4
`
`5,392,270
`
`FIG. 1
`
`LEVEL
`
`INPUT PULSE
`2–~
`
`INPUT PULSE
`2-y
`
`i
`
`FI G. 2 PRIOR ART
`
`INPUT
`SIGNAL E
`
`
`
`
`
`DELAY ELEMENT
`
`OUTPUT
`SIGNAL
`
`LSI Corp. Exhibit 1007
`Page 2
`
`

`

`U.S. Patent
`
`Feb. 21, 1995
`
`Sheet 2 of 4
`
`5,392,270
`
`F| G. 3 PRIOR ART
`
`RECORD
`INFORMATIONE
`
`F| G. 4 PRIOR ART
`
`
`
`EQUALIZER
`AMPLIFIER
`
`
`
`
`
`THRESHOLD 1
`THRESHOLD 2
`
`
`
`REPRODUCED
`INFORMATION
`
`LSI Corp. Exhibit 1007
`Page 3
`
`

`

`U.S. Patent
`
`Feb. 21, 1995
`
`Sheet 3 of 4
`
`5,392,270
`
`F| G. 5 PRIOR ART
`
`INPUT
`SIGNAL
`
`OUTPUT
`SIGNAL
`
`
`
`DELAY ELEMENT
`
`LSI Corp. Exhibit 1007
`Page 4
`
`

`

`U.S. Patent
`
`Feb. 21, 1995
`
`Sheet 4 of 4
`
`5,392,270
`
`
`
`RECORD
`INFORMATION B
`
`FIG. 7
`
`
`
`
`
`
`
`EQUALIZER
`AMPLIFIER
`
`
`
`LEVEL
`DETECTOR
`
`13—8
`CONVERTER
`
`
`
`THRESH
`ESHOLD
`
`ERROR CORRECTING
`CIRCUIT
`
`G-REPRODUCED
`INFORMATION
`
`LSI Corp. Exhibit 1007
`Page 5
`
`

`

`10
`
`15
`
`35
`
`1.
`
`INFORMATION RECORDING REPRODUCING
`APPARATUS USING DATA CONVERSION TO
`PROVIDE FOR ACCURATE REPRODUCTION OF
`HIGH DENSITY RECORDING USING AN
`OPTICAL RECORDING MEDIUM
`
`5
`
`5,392,270
`2
`1 is supplied via a digitizer 2 to an optical head 3. The
`digitizer 2 digitizes other values than “0” and “1” which
`are produced by the precoder 1, and may be designed to
`divide an input value by “2” and output the remainder.
`The optical head 3 performs photoelectric conversion
`on the output of the digitizer 2 and records the resultant
`signal on an optical disk which is rotated by a spindle
`motor 4. It is known that the precoder 1 and digitizer 2
`have a so-called NRZimodulation (Non Return to Zero
`Inverting) function that inverts the level of an output
`signal when an input signal is “1”. The record informa
`tion is therefore considered to be supplied to the optical
`head 3 via an NRZi modulator 6, which comprises the
`precoder 1 and the digitizer 2.
`FIG. 4 illustrates the structure of a conventional
`information reproducing apparatus for an optical disk.
`In reproducing information, an optical pickup 7 ac
`cesses the optical disk 5 for information reading, yield
`ing a reproduced signal. The reproduced signal is ampli
`fied by an equalizer amplifier 8 before it is supplied to a
`level detector 9. The level detector 9 digitizes the ter
`nary reproduced signal to restore it to the original re
`cord information and outputs the reproduced informa
`tion. The process the optical pickup 7 performs to read
`information from the optical disk 5 is equivalent to the
`PR (1,1) transfer path due to the code interference. The
`reproduced signal therefore is a ternary signal having
`values of “0”, “1”and “2”. The level detector 9 com
`pares the level of the signal from the equalizer amplifier
`8 with first and second threshold levels. The level de
`tector 9 is designed to output “0” when the level of the
`signal from the equalizer amplifier8 is lower than the
`first threshold level or equal to or higher than the sec
`ond threshold level, and output “1” when the level of
`that signal is equal to or higher than the first threshold
`level and lower than the second threshold level.
`In short, the conventional recording and reproducing
`systems for an optical disk designed to have a high
`linear recording density should separate and extract a
`ternary signal using two threshold levels. This separa
`tion/extraction of a signal accurately converted to have
`three values requires a higher S/N ratio in the repro
`duced signal than the separation and extraction of a
`digital signal by a single threshold level, and is therefore
`practically difficult to accomplish.
`SUMMARY OF THE INVENTION
`It is therefore an object of the present invention to
`provide an information recording/reproducing appara
`tus using an optical recording medium, which does not
`have the aforementioned shortcoming and can thus
`reproduce information from a recording medium de
`signed to have a high linear recording density, by a
`method of performing signal separation/extraction by
`one threshold level in a level detecting process at the
`time of information reproduction.
`An information recording apparatus using an optical
`recording medium according to the present invention
`comprises a data converting means for performing data
`conversion on record information consisting of a digital
`signal in accordance with a predetermined data conver
`sion table including a pattern for yielding a converted
`pattern consisting of at least one “0” and an even num
`ber of consecutive “1” or a converted pattern having a
`section consisting of “01010” and a section consisting of
`at least one “0” or an even number of consecutive “1”;
`a data modulating means for inverting an initial output
`signal when bit information of data after the data con
`
`This is a continuation of application Ser. No.
`07/914,528, filed Jul. 17, 1992, now abandoned.
`BACKGROUND OF THE INVENTION
`1. Field of the Invention
`The present invention relates to an information recor
`ding/reproducing apparatus using an optical recording
`medium such as an optical disk.
`2. Description of the Related Art
`Recording and reproducing systems for an optical
`disk can be considered as a kind of low-pass filters in
`view of the OTF (Optical Transfer Function) of an
`objective lens and the response characteristic or the like
`20
`of a recording material. If information is recorded with
`a high linear recording density increased to near the
`upper limit of the frequency response of the recording
`and reproducing systems, a read error occurs due to a
`so-called code interference by which reproduced wave
`25
`forms are likely to interfere with each other at the time
`adjacent marks are read.
`Suppose a train of signals “0,1,1,0,1” is input while
`considering the recording and reproducing systems for
`an optical disk as a single transfer path. If an input “1”
`30
`is a pulse with a level of “1” , the train of signals
`“0,1,1,0,1” is the input signal as shown in FIG. 1. The
`output shown in FIG. 1 is acquired in accordance with
`this input signal. The signal indicated by the solid line is
`output first according to the first input pulse, the signal
`indicated by the broken line is then output according to
`the next input pulse, and the signal indicated by the
`alternate long and short dash line is output according to
`the last input pulse. The final output therefore becomes
`the sum of the former two outputs as indicated by the
`alternate long and two short dashes line. The acquired
`train of output signals, “0,1,2,1,1”, differs from the train
`of input signals.
`Because of the above characteristic, with a high lin
`ear recording density accomplished, the recording and
`45
`reproducing systems for an optical disk can be said to be
`approximated to a PR (1,1) transfer path (Partial Re
`sponse Transfer Path) as shown in FIG. 2. The PR (1,1)
`transfer path shows a characteristic such that, when a
`train of input signals has a digitized value, the output
`50
`has a ternary value.
`Conventionally, therefore, by using a method of ter
`mary detection while considering the recording and
`reproducing systems for an optical disk is considered as
`a PR (1,1) transfer path, information recording and
`55
`reproduction on and from an optical disk designed to
`have a high linear recording density are accomplished
`by apparatuses having structures as shown in FIGS. 3
`and 4.
`FIG. 3 illustrates the structure of a conventional
`information recording apparatus for an optical disk.
`In recording information, record information digi
`tized to have values “0” and “1” is supplied to a pre
`coder 1. The precoder 1 modulates data before input
`ting the data to the PR (1,1) transfer path, and is equiva
`65
`lent to a transfer path which processes input data with
`the opposite characteristic to that of the PR (1,1) trans
`fer path, as shown in FIG. 5. The output of the precoder
`
`LSI Corp. Exhibit 1007
`Page 6
`
`

`

`TABLE 1
`
`13-BIT DATA
`
`10
`
`20
`
`30
`
`35
`
`5,392,270
`3
`4
`version is “1” given that the initial output signal is “0”
`Since the 8-to-13 converter 10 has no output rule to
`(NRZI modulation); and a recording means for record
`an input, a user needs to arbitrarily prepare output pat
`ing the output signal on an optical recording medium.
`terns following the above rules, and prepare a data
`An information reproducing apparatus using an opti
`conversion table which associates the output patterns
`cal recording medium according to the present inven
`with input data. Tables 1 through 9 show examples of
`tion comprises a reading means for reading information
`the data conversion table which associates the output
`from the optical recording medium to yield a repro
`patterns with input data. Tables 1 through 7 are pre
`duced signal; a level detecting means for detecting a
`pared according to the rule (1), and tables 8 and 9 ac
`level of the reproduced signal and outputting digital
`cording to the rule (2). The 8-to-13 converter 10 may be
`data; an error correcting means for, upon detection of a
`constituted of a ROM (Read Only Memory) where the
`sequence of “01110” in a bit pattern of the digital data,
`output patterns are recorded as data at addresses speci
`correcting the sequence to a sequence of “01010” and
`fied by the input data.
`outputting corrected data, and, upon detection of no
`Data after 8-to-13 conversion is supplied to an NRZi
`error, outputting the digital data; and a data reverse
`modulator 6 to become NRZi data. This NRZi data is
`converting means for performing reverse conversion on
`15
`then supplied to an optical head 3 to be recorded on an
`optical disk 5.
`the output data of the error correcting means in accor
`dance with the data conversion table, yielding repro
`duced information.
`BRIEF DESCRIPTION OF THE DRAWINGS
`FIG. 1 is a diagram illustrating a data reading error
`caused by code interference;
`FIG. 2 shows a PR (1,1) transfer path;
`FIGS. 3 and 4 are diagrams illustrating the structures
`25
`of conventional information recording and reproducing
`apparatuses using an optical recording medium;
`FIG. 5 is a diagram of a precoder; and
`FIGS. 6 and 7 are diagrams illustrating the structures
`of information recording and reproducing apparatuses
`using an optical recording medium according to the
`present invention.
`DETAILED DESCRIPTION OF THE
`PREFERRED EMBODIMENT
`In an information recording/reproducing apparatus
`using an optical recording medium according to the
`present invention, the information recording apparatus
`performs data conversion in such a way that “1” does
`not appear three or more times in a row in a train of 40
`information data at the time of recording information
`data on a recording medium, and the information repro
`ducing apparatus restores the data converted by this
`data conversion to the original information data.
`A preferred embodiment of the present invention will
`45
`be described below referring to the accompanying
`drawings.
`FIGS. 6 and 7 illustrates the structures of the infor
`mation recording and reproducing apparatuses using an
`optical recording medium according to the present
`50
`invention. The information recording and reproducing
`apparatuses perform information recording and infor
`mation reproduction in the units of eight bits.
`To begin with, in recording information data on an
`optical disk 5, the information recording apparatus in
`FIG. 6 embodying the present invention causes an 8-to
`13 converter 10 to perform data conversion before
`NRZi modulation in such a way that “1” will not ap
`pear three or more times in a row in a train of informa
`tion data after the NRZi modulation.
`60
`The 8-to-13 converter 10 performs data conversion to
`expand 8-bit input record information to 13-bit data
`according to one of the following rules.
`Rule (1): A pattern after conversion consists of at
`least one “0” and an even number of consecutive “1”.
`Rule (2): A pattern after conversion includes a section
`consisting of “01010” and a section consisting of at least
`one “0” or an even number of consecutive “1”.
`
`8-BIT
`DATA
`HEXA
`DECI
`HMAL
`NOTA
`TION
`00
`01
`02
`03
`04
`05
`06
`07
`08
`09
`0a
`Ob
`0c
`0d
`0e
`Of
`10
`11
`12
`13
`14
`15
`16
`17
`18
`19
`la
`1b
`1c
`1d
`le
`lf
`
`TABLE 2
`
`13-BIT DATA
`
`55
`
`65
`
`8-BIT
`DATA
`HEXA
`DECI
`IMAL
`NOTA
`TION
`20
`21
`22
`23
`24
`25
`26
`27
`28
`29
`
`LSI Corp. Exhibit 1007
`Page 7
`
`

`

`TABLE 2-continued
`
`TABLE 4
`
`5,392,270
`
`8-BIT
`DATA
`HEXA-
`DECI-
`IMAL
`NOTA-
`TION
`
`13-BIT DATA
`
`
`
`23567009abCdefO234567893Cderl
`
`110011111l111000OO0011000O001O10
`
`01000101]11010000l000l.1000000010
`
`0011000011101100010000ll0000O000
`
`00110000011011O101100001100101O1
`
`1111l1110111ll010110000011010101
`
`11111111011111000O00000001000000
`
`00111111l0111l000010000000000000
`
`0011111110ll11101011111111000000
`
`10000011I00lll101001111111110000
`
`11000011110111O01000000000111l00
`
`1110100011010l0010O00000O0001111
`
`11111100111l0l000001000000l000l1
`
`1101111011110000000l10O0001O1000
`
`TABLE 5
`
`03
`
`35
`
`13-BIT DATA
`1
`o
`
`0
`
`o
`
`0
`
`0
`
`o
`0
`
`o
`
`0
`
`0
`o
`
`0
`
`0
`
`o
`o
`
`o
`
`0
`
`0
`0
`
`1
`
`1
`
`0
`
`o
`
`1
`
`00
`
`8-BIT
`DATA
`HEXA-
`DECI-
`IMAL
`NOTA-
`TION
`2b
`2c
`2d
`
`0
`
`0
`
`000
`
`1
`
`8-BIT
`DATA
`HEXA-
`DECI-
`IMAL
`NOTA-
`TION
`
`TABLE 3
`
`13-BIT DATA
`
`430000
`1
`4400000
`45
`46
`47
`48
`49
`4a
`
`1
`
`1
`
`100000
`
`1
`
`45
`
`0
`
`1
`
`1
`
`0
`
`0
`
`0
`
`0
`
`50
`
`52
`
`54
`
`56
`57
`
`5c
`
`000
`
`00
`
`ll
`
`0001
`
`I
`
`1
`
`0000
`
`0
`
`1
`
`55
`
`60
`
`0
`
`0
`
`0
`
`0
`
`1
`
`8-BIT
`DATA
`
`DECI-
`IMAL
`NOTA-
`TION
`
`%NWoo%oooooooooooo%oooooooo9.n.7;99
`
`35670093cdef023
`4.67893Cde
`
`13-BIT DATA
`
`0000001000000000001000000001111
`
`0000101111l1000000l11ll1000l111
`
`00001001111l1100001111111000000
`
`000010000000111100111ll...ll00000
`
`000O1000000000111101ll11111l100
`
`1100100100001000l100000011ll111
`
`1111110l100O1O1000000000011001l
`
`00l1O101ll001010l00100000011000
`
`1000011ll11011ll110110000001010
`
`101001101lIl0lI1ll001l000000010
`
`0111011001ll010111l001101l10101
`
`010101100011010l01l0O0ll11l0l0I
`
`0000000O0001000O0O0000010000000
`
`LSI Corp. Exhibit 1007
`Page 8
`
`LSI Corp. Exhibit 1007
`Page 8
`
`

`

`8-BIT
`DATA
`HEXA-
`DECI-
`IMAL
`NOTA-
`TION
`
`8-BIT
`DATA
`HEXA-
`DECI-
`IMAL
`NOTA-
`TION
`
`
`
`wuaamwmumwammmmnwmammwmmmwmwmmmm
`
`8-BIT
`DATA
`HEXA-
`DECI-
`IMAL
`NOTA-
`TION
`
`0246./000/a..DCdCf02cdcdccmcccccccccccdfld
`
`13-BIT DATA
`
`TABLE 6
`
`13-BIT DATA
`
`10000000000000000001000010000010
`
`0001100100110100101
`
`1111111.1100000000101111011110011
`
`110lll0l10llll10111
`
`01111111111111000101111101111111
`
`1ll00llOlll11O11O11
`
`00000000011111110101111100001111
`
`ll1000l00llllO11O01
`
`00000000000000111110111100000011
`
`01111000011100001110000101001011
`
`11111111011111110110000011101101
`
`10000111100011111110100011111100
`
`TABLE 7
`
`l3-BIT DATA
`
`111ll00100O0l111l0l
`
`l111l11l.l1000l.l111l
`
`1ll00llll1ll00ll11l
`
`O0ll000111ll1lll111
`
`01000000100000001111110111111100
`
`0001l00Ol100l1l1ll0
`
`01100100010010000011111111111101
`
`0001111000100011110
`
`10110110011011100011111111111111
`
`l0l1llll00llO0lllll
`
`10011011101101111011011110110110
`
`1l101lll1l0lll0llll
`
`0E4u00001001100100011000001000010000
`Ol000ll0l1OOll000l0
`
`52
`
`03
`
`50
`
`55
`
`06
`
`56
`
`TABLE 5-continued
`
`5,392,270
`
`8-BIT
`DATA
`HEXA-
`DECI-
`IMAL
`NOTA-
`TION
`d3
`d4
`d5
`d6
`d7
`
`8-BIT
`DATA
`HEXA-
`DECI-
`IMAL
`20 NOTA-
`TION
`
`TABLE 7-continued
`
`13-BIT DATA
`
`01010
`
`11111
`
`11111
`
`11111
`
`10111
`
`10011
`
`11001
`
`11100
`
`11110
`
`01111
`
`01111
`
`11111
`
`10101
`
`TABLE 8
`
`13-BIT DATA
`
`wwmwamaawaaaaawawaawwmmamnaamsm
`
`0000001111000000000000000000000
`
`0000001111111000000000000000000
`
`1000000000111110111110000000000
`
`0100000000000111000001111000000
`
`1010001000000001111110000111000
`
`0101000100100000000001111000110
`
`0010101010010100000000000111001
`
`0001010101101011100000000000110
`
`0000100010010100.110001000000001
`
`0000010001001011011001100100000
`
`0000000000000000001100110110100
`
`0000000000000000000110011011111
`
`0000000000000000000010001001011
`
`8-BIT
`DATA
`HEXA-
`DECI-
`IMAL
`NOTA-
`TION
`
`TABLE 9
`
`13-BIT DATA
`
`nmm.m.m.mm....;n
`
`110000000
`
`111000000
`
`111111000
`
`111000110
`
`001111001
`
`000000110
`
`100000001
`
`011100000
`
`100110100
`
`011111111
`
`000111111
`
`000011111
`
`000001011
`
`A description will now be given of the information
`reproducing apparatus in FIG. 7 according to the pres-
`ent invention. An optical pickup 7 picks up information
`from the optical disk 5 and supplies the acquired repro-
`
`LSI Corp. Exhibit 1007
`Page 9
`
`LSI Corp. Exhibit 1007
`Page 9
`
`

`

`10
`
`5,392,270
`10
`duced signal to an equalizer amplifier 8. The repro
`The numbers of bits, “8” and “13”, in the 8-to-13
`duced signal amplified by the equalizer amplifier 8 is
`conversion and 13-to-8 conversion are determined for
`the apparatuses according to this embodiment, which
`sent to a level detector 11. The level detector 11 com
`pares the level of the signal from the equalizer amplifier
`perform information recording and reduction in the
`units of 8 bits, but those numbers may be arbitrarily
`8 with a threshold level as a reference for level discrimi
`nation to acquire digital data from the reproduced sig
`determined by a user as long as they satisfy the rules (1)
`and (2).
`nal. The level detector 11 sends digital data of “0” to an
`The information recording/reproducing apparatus
`error correcting circuit 12 when the level of the signal
`using an optical recording medium according to the
`from the equalizer amplifier 8 is lower than the thresh
`present invention inhibits “1”from consecutively ap
`old level, and sends digital data of “1” to the error
`pearing in data or performs data conversion to restrict
`correcting circuit 12 when that signal level is equal to or
`the number of consecutive appearing “1”to two at a
`higher than the threshold level. When a sequence of
`maximum before recording record information on a
`“01110” is present in the received 13-bit data, the error
`disk. In detecting the level of the reproduced signal,
`correcting circuit 12 corrects it to “01010” and sends
`therefore, two values “0”and “1”have only to be de
`15
`the corrected data to a 13-to-8 converter 13. When the
`tected, so that the reproduced signal does not require a
`received 13-bit data does not contain a sequence of
`S/N ratio higher than that acquired by the conventional
`“01110, “the error correcting circuit 12 performs no
`apparatus which detects three values of level, “0”,
`error correction and sends the received data directly to
`“1”and “2”. The present invention can therefore pro
`the 13-to-8 converter 13. The 13-to-8 converter 13 re
`vide an information recording/reproducing apparatus
`20
`fers to the data conversion table in the reverse manner
`for an optical recording medium designed to have a
`to the one done by the 8-to-13 converter 10 to convert
`high linear recording density.
`13-bit data to 8-bit data, and outputs the resultant data as
`What is claimed is:
`reproduced information.
`1. An information recording apparatus using an opti
`The following will discuss data transition, referring
`cal recording medium comprising:
`25
`to actual data input to the information recording/repro
`a data converting means for performing data conver
`ducing apparatus of the present invention. In this de
`sion on record information consisting of a digital
`scription Tables 1 through 9 are to be referred to as data
`signal in accordance with a predetermined data
`conversion tables for 8-to-13 conversion.
`conversion table including a pattern for yielding a
`First, data transition at the time of information recor
`converted pattern consisting of one of at least one
`30
`ding/reproduction when 8-to-13 conversion which con
`“0”and an even number of consecutive “l’s” and a
`forms to the aforementioned rule (1) will be described.
`converted pattern having a section consisting of
`When record information is “01111010” (“7A” in
`“01010” and a section consisting of one of at least
`hexadecimal notation), data after 8-to-13 conversion
`one “0”and an even number of consecutive “l’s”;
`becomes “0011011000000” from Table 4. When this
`a data modulating means for inverting an initial out
`35
`data is subjected to NRZi modulation, it becomes
`put signal when bit information of data after said
`“0010010000000” which is in turn recorded on the opti
`data conversion is “1”given that an initial output
`cal disk 5. At the time of information reproduction, data
`signal is “0”, wherein said data conversion is per
`formed on said digital signal before supplying said
`“0010010000000” becomes “0011011000000” due to
`digital signal to said data modulating means so that
`code interference. As a sequence of “01110” does not
`an output signal from said data modulating means
`appear in this data, “0011011000000” is directly sub
`always includes no more than two consecutive
`jected to 13-to-8 conversion. In the 13-to-8 conversion,
`“I’s”; and
`the data conversion table (Table 4) is referred to in the
`a recording means for recording said output signal on
`reverse manner to what is done in the 8-to-13 conver
`said optical recording medium.
`sion, so that “01111010” is output as reproduced infor
`45
`2. An information reproducing apparatus for an opti
`mation.
`cal recording medium on which information is recorded
`Next, data transition at the time of information recor
`by the information recording apparatus as recited in
`ding/reproduction when 8-to-13 conversion conform
`claim 1, the information reproducing apparatus com
`ing to the aforementioned rule (2) will be described.
`prising:
`50
`When record information is “11101000” (“E8” in
`a reading means for reading information from said
`hexadecimal notation), data after 8-to-13 conversion
`optical recording medium to yield a reproduced
`becomes “0010100110000” from Table 8. When this
`signal;
`data is subjected to NRZi modulation, it becomes
`a level detecting means for detecting a level of said
`“0011000100000” which is in turn recorded on the opti
`reproduced signal and outputting digital data;
`55
`cal disk 5. At the time of information reproduction, data
`an error correcting means for detecting a sequence of
`“0011000100000” becomes “0012100110000” due to
`“01110” in a bit pattern of said digital data and for
`code interference. Since a single threshold level is used
`correcting the sequence to a sequence of “01010”
`in the detection of the level of the reproduced signal
`and outputting corrected data, and, upon detection
`and all the levels above “1”are set to “1”in the present
`of no error, outputting the digital data; and
`invention,
`that
`data
`actually
`becomes
`a data reverse converting means for performing re
`“0011100110000.”As a sequence of “01110” exists in
`verse conversion of output data of said error cor
`this data, the data is corrected to “0010100110000”
`recting means in accordance with the data conver
`which is in turn subjected to 13-to-8 conversion. In the
`sion table, yielding reproduced information;
`13-to-8 conversion, the data conversion table (Table 8)
`wherein said error correcting means ensures that said
`65
`is referred to in the reverse manner to what is done in
`reproduced signal always includes no more than
`the 8-to-13 conversion, so that “11101000” is output as
`two consecutive “l’s”.
`reproduced information.
`# * : *k
`
`k
`
`LSI Corp. Exhibit 1007
`Page 10
`
`