Note: Descriptions are shown in the official language in which they were submitted.
1 325274
--1--
Recording Medium and Recording and
Reproducina Apparatus Employin~ the Recording l~edium
BACKGROUND OF THE INVENTION
Field of the Invention
This invention relates to a recording medium, a
recording apparatus and a reproducing apparatus
employing the recording medium, that may be employed in
a data storage system.
Prior Art
There are a variety o~ diffarent types of apparatus
for recording and reproducing data on a recording
medium, operatin~ on various r~cording/reproducing
principles or utilizing recording media having various
outer shapes.
In general, data recording media can be classified
according to the operating principle, such as the
magnetic and/or optical re~ording/reproducing principle,
and also according to the oute~ shape, such as tape,
card, or disc shaped recording media.
For example, there are disc players dedicated to
reproduc~ion, such as CD pLaysrs for reproducing a so-
called compact-disc (CD) on which audio signals such as
voice or musical sound are previously recorded in a
digitized form.
In a compact disc tCD), as shown in Fig. ~ a data
format ha~ing 98 frames as one subcode biock is
standardi æ d, wherein each ~rame is constituted by a 24-
bit sync signal, given as eight to fourteèn modulation
data, in which 1-symbol/8-bit signals are converted into
data of 14 bits (L channel bit) constituting 1 symbol of
subcode, i.e. one symbol being composed of 14 bits, 32
symbols o~ data, such as two sets of 12 symbols of play
data and 4 symbols of parity bits, with each symbol
being composed of 14 x 32 bits, and with three merging
., .~
., - :~, . .
-
v.
: .
1 325274
-2-
bits between the adjacent .symbols. Thus each frame
- includes the sum total of ~88 bits. The absolute
address of each subcode bl~ck i8 given by the Q-
channel signals of the abov~ subcode and the data such
as the play data are processed at intervals o~ one
s~bcode block.
` In CD-ROMs, as shown in Fig. 2, the le~t and right
~hannel digital audio sign~ls recorded on the compact
~isc (CD) are alternately ~nnected at intervals of one
.
lo word (2 8ymbols ~ 16 bits) ~D as to be treated as one
channel of serial data and the CD is treated as a data
storage device, a header sPction and sync signals are
: ' annexed ahead of each subcode block or 98-frames of
: ;
data in the CD data format, such that each sector or
block is constituted by 2X bytes of data.
Since the conventional CD player is dedicated to
reproduction, attempts have been made to develop a data
- stora~e medium and the recording and/or reproducing
system making use of the data çtorage medium, such as a
80 called "write once compact disc" (referred to as a
- "CD-Wo") or an erasable compact disc ~re~erred to as
"CD-erasable"). This CD-WO or CD-erasable makes use of
a magneto-optical disc which is formed by a rewritable
....
magneto-optical recording medium and which is
.
interchangeable with respect to the CD or CD-erasable,
as disclosed in EP application No. 0265695 published on
; May 4, 1988.
In the data recording/reproducing system making use
of a recording medium such as the CD-WO o~ CD-erasable,
it is necessary to control data efficiently on a block-
by-block basis. However, in the CD data format, there
are only a few address data, such that, when the data
format is used in a data storage medium such as CD-WO or
,
. ~ ~
~ 325274
CD-erasable, it is difficult to control the data on a
block-by-block basis.
OBJECTS AND SUMMARY OF THE INVENTIO~
It is a principal object of the present invention
to provide a data recording/reproducing system wherein
data can be controlled efficiently on a block-by-block
ba~
It is another ob~ect of the pr~sent invention to
~vide a recording medium ~herein ~ata can be
controlled efficiently on a ~lock--by-block basis.
It is a further object of the present invention to
provide a recording medium wherein interchangeability
can be maintained with the CD or the CD-ROM.
It is a further object of the present invention to
provide a recording apparatus and a reproducing
apparatus wherein data can be controlled efficiently on
a ~lock-by-block basis.
It is yet another object of the present invention
to provide a data recording apparatus which can cope
with the case of recording in a continuous recording
mode, as when recording musical data, or CD-ROM
recording data, and which can utilize the address on the
disc in the intermittent recording mode to provide for
high speed accessing of recording/reproducing data for
each sector as when using the apparatus as a C~-WO or as
a CD-erasable.
The above and other objects of the present
invention are attained by a recording medium having a
recording track whose width is changed in a burst-like
fashion to represent control data of a predetermined
number of bits. The control data are the address data
for each data block as one unit. The regions
containing widthwise changes of the track, and thus
including the address data, represent data record
- . ~
'~
,,,, . -
1 325274
--4--
regions or data non-record regions depending on the
recording mode, which can be either a modQ ~n which the
recorded data are sub~ected to convolution encoding or a
mode in which the recorded data are subje¢ted to sector
S complete type encoding.
In still another embodiment of the invention, the
recording medium has a recording track whose centerline
i8 periodically displaced acros the track width with
respect to an imaginary centerline of the recording
track. The track width also changes in a burst-like
fash~on, wherein period data are pre-recorded by the
deviation of the track centerline across the track width
and control data of a predetermined number of bits are
represented by the ~urst-like changes of the track
width.
The invention further includes an apparatus for
recording data on such a recording medium and including
detecting means for detecting the control data signals
recorded on the recording trac~, the detecting means
including two pairs ~f detectors, each pair being
arranged across the tracX width and producing a
separate push-pull output, and control means for
controlling the data recording operation on the
recording track based on the control data. The control
data are address data and the control means controls the
recording on the recording track based on the -'
reproduced address ~gnal~. When the recor~ing medium
has a recording track whose centerline i8 periodically
displaced across the track width with respect to an
imaginary centerline of the recording track, then the
detecting means detec~s the period data as well as the
control data and the control means controls the
recording operation ~n the recording track based on the
period data and the control data as represented by the
push-pull outputs of the detecting means.
1 325274
The above and other objects of the present
invention will become more apparent upon reading the
following description in conjunction with the
accompanying drawinge.
s
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a diagrammatic view showing the data
format of a compact disc (CD);
Fig. 2 is a diagrammatic view showing the data
format of a CD-RO~;
Fig. 3 is a diagrammatic plan view showing an
optical disc as the recording medium according to a
! first embodiment of the present invention together with
t an enlarged detail view of three of the radial trac~s
thereon;
Fig. 4 is a diagrammatic view showing an
arrangement of an optical pickup adapted for reading
data on the optical disc depicted in Fig. 3;
Fig. 5 is a diagrammatic yiew showing the data
recording state on the recording track of the optical
disc:
Fig. 6 is a block diagram showing an arrangement of
a recording/reproducing apparatus employing th~ optical
disc of the first embodiment as the recording medium;
Fig. 7 is a diagrammatic plan view of an optical
disc as the recording medium according to a seaond
embodiment of the present invention;
Fig. 8 i~ a block diagram showing the recor*ing
/reproducing apparatus employing the opticai disc of the
second embodiment as the recording medium; and
Fig. 9 i8 a waveform diagram for illustrating the
operation of the recording/reproducing apparatus.
1 325274
1$fi5EIilIQN OF THE PREFERRED EMBODI~
~eferring to the drawings, certain illuqtrative
embodiments of t~e present invention will be explained
in more detail.
Referring now to Fig. 3 wherein all or part of the
optical disc as the recording medium according to a
~irst embodiment of the present invention is
~iagrammatically æhown, a magneto-optical disc is
~ployed as the ~p~ical disc 1 in which a
~rpendicularly ~gnetized film having magneto-optical
effects is formed on a transparent base plate. The
lands sandwiched between the spirally formed pregrooves
s 2 are formed as the recording track 3 and the block data
completed by 2K bytes of data in accordance with the
above described CD-ROM data format are photo-
magnetically recorded on the recording track 3. A long
portion of the length of the spiral track 3 constitutes
the data region 6 where data are recorded.
In the recording track 3, address regions 4 are
provided at equidistant positions along the length of
the track 3 corresponding to the sync aignal (SYNC)
portion or to the error correction code (ECC) portion in
the above CD-ROM data format. Each address region 4
represents burst-like changes across the track width
whereby 19-bit address data, for example, are pre-
recorded in each address region 4. The signal spectrum
of the address data produced by the changes across the
track width is selected to represent a co~ponent higher
than that of the frequency spectrum of the servo region.
Radially interior from the data region 6 there is
formed a lead-in region 7, in which there are recorded
lead-in data indicating the recording state of the data
region 6.
;~ ~
- .
.
1 325274
--7--
In the optical disc 1 ~f the first embodiment of
the invéntion there are recorded in each address region
4 address data of a predetermined bit number by the
changes acros~ the track width. As shown in Fig. 4, a
four segment detector 10 composed of four photodetectors
A, B, C and D is used in conj~nction with a laser light
source (not shown) as a data read-out optical pickup.
Thus, a data signal RF can ~.e detected in the ~orm of a
summation output signal S~ ~ SB ~ 8c + SD obtained by
summing the outputs SA, Sg, S~, and SD of t~e respectivc
detectors A, B, C and D at an adder ll. On the other
hand, an address information signal ADR can be detected
,~ in the form of a subtraction output signal equal to tSA
~ Sg) - (Sc + SD) obtained by subtracting in a
subtractor 14 a summation output (Sc + SD) of the
outputs Sc and SD of the detectors C and D produced by
an ad~er 13 from a s~mmation output (SA + Sg) produced
by an adder 12 of the Dutputs SA and SB of the detectors
A and B, wherein the ~etectorssA, B and C, D are
arranged in the longitudinal or X - X' direction of the
recording track 3, that is, in the form of push-pull
output~ SA - SD and Sg - Sc, and the detectors A, D and
B, C are arranged in.the widthwise direction or Y - Y~
. direction of the recording track 3.
The address information ADR does not substantially
affect the data signal RF. Thus, as shown in ~ig. 5,
the ~ta recordlng region 5 can be extended up to and
thrcugh the address region 4 of the recording track 3.
In the above described optical disc 1~, the address
regions 4 are provided at predetermined intervals along
the l~ngth of the signal track 3, wherein the address
information o~ the signal spectrum above the servo
regian is indicated as changes across the track width,
so that the block data completed by 2K bytes of data in
accordance with the CD-ROM data format can be recorded
.: - -
-
1 325274
--8--
on or reproduced from the recording track 3 on the basis
of the above address information without the tracking
servo or focusing servo for the recording track 3 being
disturbed by the address in~ormation or data.
Data recording can be made in two modes on the
optical disc 1. one of such modes is that for the above
described continuous recording. This mode for
continuous recording is convenient for direct recording
of CD-ROM data or of sequential data, such as musical
data.
In this continuous recording mode, there is no time
period which is devoid of data, so that, as shown in
s Fig. 5, the pits 5 are also formed in the address region
4, which is used simultaneously as the data record
region.
The other mode i8 the mode for intermittent
recording, which is convenient for recording data at
randomly selected addresses, as in the case o~ CD-WO or
CD-erasable. ~
The basic data structure for such an intermittent
recording mode is similar to that for continuous
rding except that the 12-byte sync signals for
musical signal blocking in the data format shown in Fig.
2 are not provided for in the intermittent record mode,
in which data are recorded with a 98 frame sect~r as
one recording unit. In each of these sectors,~there are
recorded the same dat~ as those of the data format shown
in Fig. 2 except the 12-byte sync signals Sor blocking
the musical signals.
Thus, in the intermittent recording mode, a vacant
region equivalent to 12 bytes can be procured in each
sector having a total data capacity of 2352 bytes. This
12-byte vacant region corresponds to the address region
4.
' ' ~ , .
~ .
1 32527~
g
Therefore, when data are recorded in the
intermittent record mode, no data are recorded in the
address regions 4, so that the address data recorded in
the address regions are left over a~ter data recording.
Thus, the address information recorded in the address
regions 4 can be resorted to for seeking desired
sectors.
In the intermittent recording mode, the encoding
co~ple~ed in each sector is used instea~ of convolution
e~coding. Encoding complete in each sector can be
realized by a method described in, for example, the
Japanese Patent Application No. 118567/1988. The
merging bit at the time of recording with EFM modulation
is reset at each sector.
Fig. 6 shows diagrammatically the digital data
recording/reproducing apparatus to which the present
invention is applied. This apparatus is designed to
record or reproduce digital da~ optically by using the
optical disc 1 shown in Fig. 3~as the recording medium,
and is provided with a recording circuit 110 and a
reproducing circuit 120.
The optical disc 1 is pro~i~ed with the above
described address regions 4 in each of which ar~
recorded physical address data as burst-like changes of
the track width. The disc 1 performs a revolution at a
constant linear velocity (CLV3.
The recording circuit 110 can be set to the above
described continuous record an~ intermittent record
modes responsive to select signals from the terminal
114.
The 12-byte sync signals are provided in each
sector for the continuous record mode but are not
provided for in the intermittent record mode.
During recording, data to be recorded on the
optical disc 1 are supplied from a data input terminal
- .~
, . ,~
1 325274
--10--
111 to an encoder 112 of the recording circuit 110. The
address of the optical disc 1 can be obtained from the
address information recorded in the address information
4 80 that a desired address can be souqht to record the
data therein. The data from the data input terminal 111
are developed in the encoder 112 into a predetermined
frame structure for annexing duplex error correction
codes of the Cl and C2 series. This encoding is by the
convolution encoding ~or continuous record mode and by
the sector-complete encoding for the intermittent record
mode. The data to which the duplex error correction
codes are annexed at the encoder 112 are eight to
fourteen modulated at the EFM circuit 113 so as to be
t recorded in the sector of the optical disc 1 bearing the
desired address.
In the continuous record mode, data are recorded in
the address regions 4 provided on the optical disc 1.
Conversely, in the intermittent r~cord mode, no data are
recorded in the address region~ 4 of the optical disc 1
so that the address data recorded in these address
regions 4 as the burst-like changes of the track width
remain unaf~ected.
The data recorded on the disc 1 can be reproduced
by a sequence which is the reverse of the above
described sequence adopted for recording.
Thus, the above described continuous reco~d or
interm~tt~nt modes can be set in the reproducing ci~;t
120 depending on the select signals from the terminal
124.
The reproduced data from the disc 1 are eight to
fourteen demodulated at t~e EFM demodulating circuit 121
of the reproducing circuit 120 before being supplied to
the decoder 122. Depending on the select signals from
the terminal 124, the decoder 122 is switched between
decoding processing corresponding to convolution
: . ' ' ^ ''.
' '
.. ~ - .
.
. - ~ , - .
~ 32527~
encoding for the continuous record mode and that
corresponding to the sector complete encoding ~or the
intermittent record mode, with the decoded output being
transmitted as the reproduced data at the output
terminal 123.
When seeking the desired sector during
reproduction, the information of the Q-channel o~ the
subcode can be utilized in the continuous record mode.
If the frequency spectrum of the address data recorded
in the address regions 4 of the disc 1 in the ~or~ o2
the burst-like changes of the track width and thQ
frequency spectrum of the data recorded by pit3 or the
' tracking signals are designed to be separablQ ~roM each
other, the address data recorded in the address region 4
can be used to seek the desired sector even when the
recording is made with the continuous record mode.
In the intermittent record mode, the addres~
~nformation of the address regions 4 o~ the optical disc
1 are left over so that the add~ress data recorded in the
~O address regions 4 can be utilized in seeking the desired
address.
In the above described optical disc o~ the present
invention, address regions, each of a predet~rminQd
length, are provided at predetermined spacings along the
track length and the physical address data are recorded
in these address regions in the form of the changes of
the track width, suc~ that th~ addre~s data r~¢orded in
these address regions can be utilized for writing the
data in the desired sector.
The address data in the address regions are not
recorded as the pits, so that data can be recQrded ~n
these address regions when the record data are recorded
in the continuous record modes, as when recording
musical data or CD-ROM data.
~, .... . .
,
1 325274
-12-
In the intermittent record mode for CD-WO or CD-
erasable, the 12~byte eync pattern represents a vacant
region which can be in registration with the address
~ægion 4. In this case, the address data recorded in
the address region 4 are left over after the data
.recording such that the address data of the address
~gion 4 can be utilized to perform a high speed
accessing when seeking the desired sector.
Therefore, according to the present invention, the
~dress_data on the disc ,can be utilized when the
~resent apparatus is used as a CD-WO or CD-erasable,
while the interchangeability with a CD-ROM remains
'J intact.
~urning now to Fig. 7 which depicts an optical disc
as the recording medium according to a second embodiment
of the present invention, an optical disc 21 has a land
between spirally formed pregrooves 22 as a recording
-track 23. The centerline ~1 f the recording track is
deviated at a predetermined per~iod across the track
width or Y-Y' direction with respect to an imaginary
centerline lo. The recording track 23 has its width
changed in a burst-like manner. Similarly to the
optical disc 1 of the foregoing first embodiment, the
2K-byte complete block data in accordance with the
aforementioned CD-ROM data format are recorded photo-
magnetically on the track 23.
In the optical disc 21 of the present second
embodiment, the recording track 23 is in the form of a
sinusoidal wave for affording predetermined period data
WCK corresponding to a sampling frequency of 22.05 kHz
which is one half the data sampling frequency 44.1 kHz
of the CD-RON. In addition, there are formed address
regions 24 at predetermined intervals and in register
with the sync signal SYNC or error correction signal ECC
in the CD-ROM data format, wherein the address regions
" ' ' ' ,
1 325274
-13-
24 are each formed as burst~ e track changes across
the track width. The address *ata of, for example, 19
bits, are pre-recorded by these track changes in the
widthwise direction. The signal fipectrum of the addre~
data ~ormed by the track width change is selected to be
higher than the signal s~ectrum ~f the servo region.
Radially inside of the data region 26 of the
optical disc 21, there is formed a lead-in region 27,
into which there are recorded-the lead-in data
indicating the recording s~ate ~ the data region 26.
In the present second e~bol~ment the data signals
RF can be detected as the sum~a~ion output signal ~SA +
8B ~ SC + SD) from the adder 11 while the period
information WCK and the address data ADR can be detected
as the subtraction output signal (SA + Sg) - (Sc + SD)
from the subtractor 14 by utilizing the four segment
detector 10 shown in Fig. 4 as in the case of the above
described first embodiment of t~e present invention.
The block view of Fig. 8 s~hows the arrangement of
GO the recording/reproducing apparat~ wherein the optical
disc 21 shown in Fig. 7 is used as the recording medium.
The recording/reproducing ~pparatus is 80 designed
that the recording track 23 of the optical disc 21 i8
scanned optically by means of an optical pickup 31 for
recording/reproducing data formulated in accordance with
the above described CD-ROM data format, while ~he disc
21 is rotated at a constant linear velocity by a spindlQ
motor 30.
The optical pickup 31 is mainly constituted by a
laser diode (not shown) which outputs a laser beam for
data recording/reproduction, a photosensor for optically
detecting data in the form of reflected light from the
recording track of the optical disc 21, and an optical
system (not shown) for irradiating the optical disc 21
with the laser beam from the laser diode and
~ 325~7~
-14-
transmitting the re~lected return beam from the disc 21
towards the phDtodetector. The optical pickup 31
includes two ~ur segment photodetectors 32, 33 as the
photosensor, ~nd is~so arranged that the return laser
beam from the disc 21 is transmitted to the ~our-segment
photodetectors 32, 33 after separation into a P
polarized component and an S polarized component in the
optical system (by means not shown).
As for th~ detection output from the four-segment
photodetect~r 32, t~ which the P polarized component of
the return beam is transmitted, the outputs SA and SB of
the detectors A and ~, arrayed in the longitudinal
' direction (X - X' direation) of the recording track 23
r of the disc 21, are supplied to an adder 34, while theoutputs Sc, SD of the detectors C and D are supplied to
an adder 35.
The summation output signal ~SA + Sg) from the
adder 34 is supplied to adders 36 and 37, while th~
summation output signal (Sc + SD) from the adder 35 is
~upplied to the adder 36 and an adder 41.
As for the detection output ~rom the four segment
photodetector ~3, to which the S polarized component of
the return b~am is transmitted, the outputs SA' and SB'
of the detector Al and B' arrayed in the longitudinal
direction (X - X' direction) of the recording track 23
of the disc 21 are supplied to an adder 38, whi~e the
outputs Sc~, S~ of the detectors C~ and~D' are supplied
to an adder 3~.
The summation output signal (SA' + SB') from the
adder 38 is supplied to the adder 37 and an adder 40
whereas the summatlon output signal (Sc' + SD') from the
adder 39 is supplied to the adder 40 and the adder 41.
The summation output signal (SA + Sg + Sc +SD) by
the adder 36 and the summation output signal (SA' + SB'
+ Sc' + SD') by the adder 40 are supplied to a
1 32~27~
-15-
.subtractor 42, whereby a reproduced RF s~gnal or RFS,
where:
RFS ~ (SA + Sg + Sc + SD) - (SA' + SB + SC + SD )
is produced as the subtraction output ~i~pual from the
subtractor 42.
This reproduced RF signal or RFS is supplied to a
reproducing block 43, where the operation Df reproducing
the 2K byte complete block data formed in accordance
with the above described CD-ROM data forma~. and
~0 ph~tomagnetic~lly recorded on the record ~rack 23 of the
optical disc 21 is performed under the c~l~rol og a
system controller 100 to reproduce the block data from
' the reproduced RF signals tRFS).
on the other hand, the summation output signal (SA
+ SB + SA' + Sg') from the adder 37 and the summation
output signal (Sc + SD + Sc' + SD') from the adder 41
are supplied to a subtractor 44, from which a
subtraction output signal RFC, where:
RFC = (SA + Sg + BA' + Sg') - ;(Sc + SD + Sc' + SD )
~.0 is pro.duced and.sllpplied to a control block 50.
At the input stage of the control block 50, the
output of the subtractor 44 is supplied to a bandpass
filter 51 making use of a tank circu~t having ~ high Q
and a resonance frequency of 22..0~ kHz for separati~
the reproduced control signals RFC from the 22.05 kHz
sinusoidal signal component suppLiQd from the ~ecording
track 22 o~ the disc 21 having.th~-shap~ of the
sinusoidal wave. The sinusoidal.waw~ signal component
corresponds to the predetermined period information WCK.
The output of the subtractor 44 is also supplied to a
high-pass filter 52 for separating the address data
component ADR, pre-recorded in the recording track 22 of
the disc 21 as the track width changes, from the
reproduced control signals RFC.
, . ' :
,
. .
!
1 325274
-16-
The sinusoidal wave signals (Fig. 9) corre3ponding
to the predetermined period data (WCK), which signal~
are separated by the bandpass filter 51, are supplied to
phase comparators 53 and 54, while the address data
component signals ADR, separated from the reproduced
control signals RFC at the highpass filter 52, are
supplied to a phase comparator 55 and an address decoder
56.
The phase comparator 53 performs a phase com~arison
~etween a reference phase signal from a refere~ce
oscillator 57 for spindle servoing and the
aforementioned sinusoidal wave signal obtained at the
bandpass filter 51 and transmits the comparison output
via a phase compensation circuit 58 to a driving circuit
59 of the spindle motor 30 to constitute a spindle servo
system for rotationally driving the optical disc 21 at a
constant linear velocity.
The phase comparator 54 performs a phase comparison
between the output of a frequency divider 61, which
divides the oscillation output of a voltage controlled
oscillator 60 by a factor of 196, and the aforementioned
sinusoidal wave signal obtained at the bandpass filter
51. The comparison output is transmitted through at low
pass filter 62 to a signal adder 63 whose output ~s
supplied to the control input terminal of the voltage
controlled oscillator 60. Together, the circuits 54,
60, 61, 62 and 63 constitut~ a so-called phasQ lock
loop (PLL) type clock reproducing system whereln t~e
oscillation phase of the voltage controlled oscillator
60 is matched to the phase of the aforementioned
sinusoidal wave signal.
The phase comparator 55 performs a phase comparison
between the oscillation output of the voltage controlled
oscillator 60 and the signal of the address data
component ADR produced at the output of the highpass
1 325274
-17-
filter 5~ and transmits the c~mparison output through a
lowpass filter 64 to the signal adder 63 v$a a switch 65
to constitute a so-called PLL ~ontrol æystem wherein
the oscillation phase of the voltage controlled
oscillator 60 is matched to the bit clock phase of the
addrecc data (ADR).
The switch 65 is controlled by an output of the
phase comparator 54 of the clock reproducing system so
as to be closed initially and opened when the
oscillation phase of the voltage controlled oscillator
60 i8 phase-locked to the sinusoidal wave signal.
Preferably, the control is so made that, after the bit
~t clock phase of the address data ADR has been detected
f correctly, the switch 65 is closed only during the
address period.
Under PLL control by the comparison outputs of the
phase comparators 54, 55, the voltage controlled
oscillator 60 outputs system clocks having the frequency
of 4.3218 MHz matched to the b * clock phase of the
address data ADR.
The system clocks produced by the voltage
controlled oscillator 60 are supplied to the system
controller lOQ adapt0d to control the operation of the
recording/ reproducing apparatus, while being supplied
simultaneously to the address decoder 56 and the record
data buffer memory 90.
From the signals of the address data ADR produced
at the highpass filter 52, the addresc decoder 56
decodes the address data ADR on the basis`of the system
clocks and transmits the address data ADR to the system
controller 100.
In the record mode, the system controller 100
controls the data buffer memory 90 supplied with the
recording data and transmits the record data from the
data buffer memory 90 to the recording processor 91 as
:
- '
- .
. .
1 32527~
-18-
the control is made for each data block as one unit
based on the address data ADR. The recording operation
is controlled so that the block data completed by 2K
bytes in accordance with the CD-RON data format will be
photomagnetically recorded on the record track 23 of the
optical disc 21.
In the reproducing mode, the system controller 100
controls the data processing operation by the
reproducing processing block 43 for reproducing the
block data completed with 2K bytes, while performing
control on a block-by-block basis using the address
data ADR. The 2-byte complete block data are formed in
accordance with the CD-ROM data format and are
photomagnetically recorded on the recording track 23 of
the optical disc 21.
In the recording medium of the present invention,
the recording track width is changed in a burst fashion
at regular intervals along the track length such that
the control data having a predetermined number of bits
are pre-recorded by the changes across the track width
as the information for performing a~ block by block
control of the recording data using the control data.
In the recording medium of the present invention,
the track centerline is periodically displaced across
the track width with respect to the imaginary track
centerline, while the track width is changed i~ a burst-
like fashion. In this manner, the period data are
recorded previously by the deviation acro~ the track
width of the track centerline as the,data~for block-by-
block control of the record data. Simultaneously, thecontrol data having a predetermined number o~ bits are
pre-recorded by the track width changes such that a
block-by-block control of the recording data can be made
on the basis of the period data and control data.
' `
1 325274
--19--
According to the optical disc o~ the present
invention, one subcode block is constituted by a
predetermined frame, and the absolute address data can
be pre-recorded as the control data in the form o~
record track width changes, so that the absolute
address data of one sub-block can be obtained by reading
out the one sub-block in its entirQty. Thus the data
recorded or reproduced by the medium of the record track
can be controlled on the basis of the above address data
so that the data can be controlled efficiently for each
block completed with 2K bytes. In addition, even when
the data of the CD or CD-R~M data format are recorded on
the recording track, the address data o~ a
predetermined number of bits pre-recorded as the changes
in the width of the recording track do not affect the
data of the CD or CD-ROM format, so that
interchangeability can be maintained with respect to the
CD or CD-ROM.
Also, according to the recGrding apparatus of the
~0 present invention, the recording operation is controlled
by the control means on the basis of the control or
period data and control data detected from the recording
medium by detection means so that block-by-block control
o~ the recording data can be performed simply and
reliably.
In addition, according to the reproducing~apparatus
of the present invention, the reproducing operation i~
controlled by control means on the basis of the control
or period data and control data detected from the
recording medium by detecting means so that block-by-
block control of the recording data can be performed
simply and reliably.
Although the present invention has been shown and
described with respect to preferred embodiments, various
changes and modifications which are obvious to a person
, ~ ., . -. .
7 .~
: ' ' :: '.'
1 325274
-20-
ækilled in the ~rt to which the invention pertains are
deemed to lie ~ithin the spirit and scope of the
invention.
.
:- . .,.. ~ . - . .
. . , -
-
