U.S. patent application number 10/828327 was filed with the patent office on 2004-10-07 for scrambler and scrambling method.
This patent application is currently assigned to Samsung Electronics Co., Ltd.. Invention is credited to Shim, Jae-seong.
Application Number | 20040196974 10/828327 |
Document ID | / |
Family ID | 19602923 |
Filed Date | 2004-10-07 |
United States Patent
Application |
20040196974 |
Kind Code |
A1 |
Shim, Jae-seong |
October 7, 2004 |
Scrambler and scrambling method
Abstract
A scrambler and scrambling method. The scrambler has a random
data generator which generates random data having a random data
generation cycle based on a result obtained by multiplying at least
a size of a first data frame by a result obtained by dividing a
data amount of two tracks in an outermost circumference of an
optical disc by a size of a second data frame. The scrambler is
advantageous in generating a stable servo signal and suppressing a
DC component in modulation in a high density disc system using the
optical disc.
Inventors: |
Shim, Jae-seong; (Seoul,
KR) |
Correspondence
Address: |
STAAS & HALSEY LLP
SUITE 700
1201 NEW YORK AVENUE, N.W.
WASHINGTON
DC
20005
US
|
Assignee: |
Samsung Electronics Co.,
Ltd.
Suwon-si
KR
|
Family ID: |
19602923 |
Appl. No.: |
10/828327 |
Filed: |
April 21, 2004 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
10828327 |
Apr 21, 2004 |
|
|
|
09620462 |
Jul 20, 2000 |
|
|
|
Current U.S.
Class: |
380/210 ;
348/E7.056; 386/E5.004 |
Current CPC
Class: |
H04N 5/913 20130101;
H04N 2005/91364 20130101; G11B 20/10 20130101; H04N 21/42646
20130101; H04N 7/1675 20130101; G11B 2220/2579 20130101; H04N
21/2347 20130101; G11B 20/1833 20130101 |
Class at
Publication: |
380/210 |
International
Class: |
H04N 007/167 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 20, 1999 |
KR |
99-29280 |
Claims
What is claimed is:
1. A recording/reproducing apparatus comprising; a data scrambler
having a random data generator for generating random data in a
cycle of 32 KB in order to scramble data having structure of 2 KB
for a sector or a data frame and 64 KB for an ECC block.
2. The apparatus of claim 1, wherein the random data generator
comprises: a 15-bit serial register r.sub.0 through r.sub.14 for
generating the random data by shifting left synchronized with a
clock input for scrambling; and an exclusive OR gate for outputting
an exclusive OR value exclusive-ORing output from a higher-most
register r.sub.14 and output from a lower register r.sub.10 to a
lower-most register r.sub.0, wherein the scrambler includes an
exclusive OR logic circuit which supplies a result of
exclusive-ORing 1-byte input data D.sub.0 through D.sub.7 and each
of the 8 outputs of lower registers r.sub.0 through r.sub.7 after
left-shifting the 15-bit register r.sub.0 through r.sub.14 8 times.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This is application is a continuation of prior U.S. patent
application Ser. No. 09/620,462 filed Jul. 20, 2000. This
application claims the benefit of Korean Application No. 99-29280,
filed Jul. 20,1999, in the Korean Patent Office, the disclosure of
which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to data scrambling, and more
particularly, to a scrambler and a scrambling method appropriate
for a high density disc system.
[0004] 2. Description of the Related Art
[0005] In general, the goal of data scrambling is to protect data
from users who do not have key. For telecommunications, data
scrambling is a widely used randomizing method for security
communications purposes.
[0006] An optical disc system using an optical disc, such as a
compact disc-read only memory (CD-ROM) or a digital versatile disc
(DVD), adopts a random data generator which randomizes certain data
input into a scrambler.
[0007] The first reason for scrambling input data in an optical
disc system is to smoothly perform tracking control using
differential phase detection (DPD). If identical data are input and
the same modulated codes of the identical data are recorded in
neighboring tracks on a disc, DPD signals are not detected during
reproduction and tracking control in a servo unit becomes
difficult. For example, in an unscrambled CD-audio disc, DPD
control becomes difficult in a section between songs (a section in
which data are all "00h").
[0008] The second reason for scrambling is to help reduce a burden
to control suppression of a direct current (DC) component in a
modulator. When identical data are continuously input, digital sum
value (DSV) control may be impossible for some values. In order to
prevent such worst cases, randomizing is needed. Here, the DSV is a
parameter for predicting the DC direction, and it is preferable
that a modulated code word has a characteristic of converging into
a DC value.
[0009] The third reason for scrambling is to protect certain data.
In the case of a CD-ROM, in order to protect a synchronization
pattern (00h, FFh, FFh, . . . , FFh, 00h) in data, scrambling is
performed on all data except synchronization data.
[0010] Referring to FIG. 1, the periodicity of a scrambler for a
general DVD system will now be explained. Since the length of a
channel bit is 0.133 m, the physical length of a sector is 5.146 mm
(=0.133 m.times.1488.times.26), the radius of the innermost
circumference of a disc 5 is 24 mm (as shown in FIG. 1), the track
length of the innermost circumference is 150.8 mm (=2.pi.r) and the
track capacity of the innermost circumference is 29.3 sectors
(=150.8 mm/5.146 mm). In addition, since the radius of the
outermost circumference is 58 mm as shown in FIG. 1, the track
length of the outermost circumference is 364.42 mm (=2.pi.r) and
the track capacity of the outermost circumference is 70.82 sectors
(364.42 mm/5.146 mm).
[0011] For DPD control, the cycle of random data generation of a
scrambler must be equal to or greater than 141.64 sectors (=70.82
sector.times.2) in the outermost circumference. Identical data
repeating within 29.3 sectors in the innermost circumference do not
cause any problem in DPD control.
[0012] FIG. 2 illustrates a circuit diagram of a scrambler in a DVD
system, in which an exclusive-or (XOR) gate 10 and 15 registers
r.sub.0 through r.sub.14 for supplying random data are referred to
as a random data generator. The random data generator and XOR gates
11 through 18 are referred to as a scrambler.
[0013] The 15 registers r.sub.0 through r.sub.14 in FIG. 2 perform
left shifting in synchronization with a clock signal for
scrambling, which is not shown in FIG. 2. During the scrambling, an
XOR value obtained from XOR gate 10 by XORing the output of the
most significant register r.sub.14 and the output of the 11.sup.th
lowest register r.sub.10, becomes an input value to the least
significant register r.sub.0.
[0014] The cycle of random data generation of the random data
generator in FIG. 2 is 32K (kilobytes), and matches the 32K-size of
1 error correction code (ECC) block of a DVD. That is, random data
without a periodicity are generated in one ECC block, and after
left-shifting the 15 registers r.sub.0 through r.sub.14 8 times,
the result D.sub.01 through D.sub.07 of XORing each of the 8
outputs of the lower registers r.sub.0 through r.sub.7 and 1-byte
input data D.sub.0 through D.sub.7 in XOR gates 11 through 18 is
obtained as the result of scrambling. Here, the data clock speed of
XOR gates 11 through 18 is an eighth of the scramble clock speed of
the registers r.sub.0 through r.sub.14, which is not shown in FIG.
2.
[0015] In the meantime, since scrambling is performed after
left-shifting the 15 registers r.sub.0 through r.sub.14, 8 times,
registers r.sub.0 through r.sub.14 are initialized by preset
values, referring to the upper significant 4 bits (ID 7:4) in the
last one byte in a 4-byte identification code (ID) allocated to
each sector. At this time, selection of initial values needs to be
handled carefully. That is, even if identical data are input,
random data must be generated using the identical initial value in
a sector, and random data in this sector are repeated by the
identical initial value for one ECC block (16 sectors).
[0016] As shown in FIG. 3, the first initial value of registers
r.sub.0 through r.sub.14 "0001 h" and the result of left-shifting
"0001h" 7 times are 0002h, 0004h, 0008h, 0010h, 0020h, 0040h,
0080h; the result of left-shifting 7 times "5500h", the value of
registers r.sub.0 through r.sub.14 after 16K (=2K.times.8) capacity
required for the return of the values 0001h, 0002h, 0004h, 0008h,
0010h, 0020h, 0040h, 0080h, are 2A00h, 5400h, 2800h, 5000h, 2001h,
4002h, 0005h; and 0001h, 0002h, 0004h, 0008h, 0010h, 0020h, 0040h,
0080h, 5500h, 2A00h, 5400h, 2800h, 5000h, 2001h, 4002h, 0005h,
which are used for initial values of r.sub.0 through r.sub.14.
[0017] The scrambler of FIG. 2 uses all of the 32K of random data
generated by the random data generator, and sector data in one ECC
block are repeated. However, the scrambler of FIG. 2 does not have
the DPD control problem mentioned in FIG. 1. In addition, since
random data are generated for one sector during modulation, there
is no DSV control. Using the initial values of registers shown in
FIG. 3, identical data are not generated contiguously between ECC
blocks during 256 sectors (=1 ECC block (16 sectors).times.16 times
initialization). Therefore, since identical code data do not occur
in contiguous tracks in the outermost circumference of a disc,
there is no problem in DPD control.
[0018] However, the previous random data generator and the
scrambler using the random data generator cannot respond properly
when generation of random data having a cycle greater than 32K and
corresponding scrambling are required.
SUMMARY OF THE INVENTION
[0019] To solve the above problems, it is an object of the present
invention to provide a scrambler appropriate for high density
optical disc systems, by controlling the cycle of random data
generation.
[0020] It is another object to provide a scrambler which is
advantageous in generating stable servo signals and suppressing a
direct current (DC) component in modulation.
[0021] It is still another object to provide a method of scrambling
which is appropriate for high density optical disc systems, by
controlling the cycle of random data generation.
[0022] It is yet still another object to provide a method of
scrambling which is advantageous in generating stable servo signals
and suppressing a direct current (DC) component.
[0023] Additional objects and advantages of the invention will be
set forth in part in the description which follows and, in part,
will be obvious from the description, or may be learned by practice
of the invention.
[0024] To accomplish the above and other objects of the present
invention, there is provided a data scrambler for a high density
optical recording/reproducing apparatus, the data scrambler having
a random data generator which generates random data having a random
data generation cycle based on a result obtained by multiplying at
least a size of a first data frame by a result obtained by dividing
a data amount of two tracks in an outermost circumference by a size
of a second data frame
[0025] There is also provided a data scrambling method using a
random data generator for a high density optical
recording/reproducing apparatus, the data scrambling method
comprising generating random data having a random data generation
cycle based on a result by multiplying at least the size of a first
data frame by a result, which is obtained by dividing a data amount
of two tracks in an outermost circumference of a disc by a size of
a second data frame.
[0026] Additional objects and advantages of the invention will be
set forth in part in the description which follows and, in part,
will be obvious from the description, or may be learned by practice
of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] These and other objects and advantages of the invention will
become apparent and more readily appreciated from the following
description of the preferred embodiments, taken in conjunction with
the accompanying drawings of which:
[0028] FIG. 1 is a general diagram showing an inner circumference
and an outer circumference of a disc;
[0029] FIG. 2 illustrates a circuit diagram of a scrambler in a
general digital versatile disc (DVD) system;
[0030] FIG. 3 is a table showing initial values used in registers
shown in FIG. 2;
[0031] FIG. 4 illustrates a circuit diagram of an embodiment of a
scrambler for a high density disc system according to the present
invention;
[0032] FIG. 5 is a table showing initial values of registers used
in the 8-bit shift-scrambler shown in FIG. 4;
[0033] FIG. 6 illustrates a generalized circuit diagram of a
scrambler for high density disc system to explain the present
invention;
[0034] FIG. 7 is a table showing branch values when a random data
cycle is 64K and the number of effective branches is 4 in the
random data generator shown in FIG. 6;
[0035] FIG. 8 is a table showing initial values of registers used
in a 1-bit shift-scrambler for a high density disc system according
to the present invention;
[0036] FIG. 9 is a circuit diagram of another embodiment of a
scrambler for a high density disc system according to the present
invention; and
[0037] FIG. 10 is a table showing the control values for changing
the structure of a scrambler, shown in FIG. 9, in the units of 4K
cycle.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0038] Reference will now made in detail to the present preferred
embodiments of the present invention, examples of which are
illustrated in the accompanying drawings, wherein like reference
numerals refer to the like elements throughout. The embodiments are
described below in order to explain the present invention by
referring to the figures.
[0039] Hereinafter, embodiments of the present invention will be
described in detail with reference to the attached drawings. The
present invention is not restricted to the following embodiments,
and many variations are possible within the spirit and scope of the
present invention. The embodiments of the present invention are
provided in order to more completely explain the present invention
to anyone skilled in the art. Like reference numerals refer to like
elements throughout.
[0040] First, the periodicity of the scrambler in a high density
DVD system will be explained.
[0041] When it is assumed that compared to a general DVD, an HD-DVD
has the same innermost circumference and outermost circumference,
but has a line density which is twice as high, the track length of
the innermost circumference is 150.8 mm (=2.pi.r.times.24 mm), the
track capacity of the innermost circumference is about 120 KB
(=60.times.2 KB), the track length of the outermost circumference
is 364.42 mm (=2.pi.T.times.58 mm), and the track capacity of the
outermost circumference is about 284 KB (=142.times.2 KB).
[0042] When it is assumed that the line density of an HD-DVD is
twice as high as that of a DVD, the cycle of random data generation
of a scrambler in the outermost circumference must be equal to or
greater than 564(=284K.times.2) in order to control DPD, and even
when identical data are repeated within 120K, no DPD control
problem occurs in the innermost circumference.
[0043] However, in an HD-DVD, the structure of a scrambler changes
depending on whether or not the size of a sector will be 2 KB, or 4
KB, or whether or not the size of an ECC block will be 32 sectors,
or 16 sectors, which will now be explained in detail.
[0044] First, for the structure of a scrambler for an HD-DVD system
having 2 KB for a sector and 32 sectors for an ECC block, the
scrambler for a general DVD system shown in FIG. 2 can be used.
[0045] That is, since 120K, the track capacity of the innermost
circumference, is greater than one ECC block (64 KB) and smaller
than two ECC blocks (128 KB), the initial value of each sector in
an ECC block can be set to an identical value. In order to prevent
repeating of the same data of two tracks in the outermost
circumference, a periodicity equal to or more than 564 K is needed.
With only 16 initial values, the cycle of random data generation
becomes 1024 K (=1 ECC block (64 KB).times.16), which is greater
than 564 KB and causes no problem. Therefore, the same structure as
that of the scrambler for a general DVD system shown in FIG. 2 can
be used for an HD-DVD system.
[0046] Next, for the structure of a scrambler having 4 KB for a
sector and 16 sectors for an ECC block, the scrambler for a general
DVD system cannot be used, and the structure of a scrambler must be
changed.
[0047] Since 120 K, the track capacity of the innermost
circumference, is greater than one ECC block (64 KB) and smaller
than two ECC blocks (128 KB), the initial value of each sector in
an ECC block can be set to an identical value.
[0048] Also, in the outermost circumference, in order to obtain a
periodicity equal to or more than 564 K, the cycle of random data
generation becomes 1024 K (=1 ECC block (64 KB).times.16) with only
16 initial values, which causes no problem. However, since the
cycle of random data generation of the random data generator of the
scrambler must be equal to or greater than 64 KB (=1 sector (4
KB).times.16), the structure of the scrambler in a general DVD as
shown in FIG. 2 cannot be used.
[0049] Therefore, the present invention proposes three types of
scramblers, having a cycle of random data generation equal to or
greater than 64 K.
[0050] The first structure of a scrambler according to the present
invention is shown in FIG. 4, and the structure of the scrambler
for an HD-DVD system has some similarities to that of a scrambler
for a general DVD system shown in FIG. 2.
[0051] That is, 16-bit random data is generated in 16 registers
r.sub.0 through r.sub.15, and the result D.sub.01 through D.sub.07
of scrambling through XOR gates 111 through 118 1-byte of input
data D.sub.0 through D.sub.7 and outputs of the lower 8 registers
r.sub.0 through r.sub.7 is provided. The XOR gate 103 XORs the
output of the most significant register r.sub.15 and the output of
the register r.sub.13, the XOR gate 102 XORs the output of the XOR
gate 103 and the output of the register r.sub.12, and the XOR gate
101 XORs the output of the XOR gate 102 and the output of the
register r.sub.10 and feeds back its output to the least
significant register r.sub.0.
[0052] FIG. 5 is a table showing initial values of registers used
in the 8-bit shift-scrambler for an HD-DVD system shown in FIG. 4.
Scrambling is performed in units of 1 byte between the bits of the
lower 8 registers r.sub.0 through r.sub.7 and 1 byte of input data
D.sub.0 through D.sub.7, after 8-bit left-shifting the output of
the registers r.sub.0 through r.sub.15. Therefore, for the initial
values of the registers, 0001h and the values obtained by
left-shifting 0001h (0002h, 0004h, 0008h, 0010h, 0020h, 0040h,
0080h), and 7E80h, which is the result of registers r.sub.0 through
r.sub.15 after 32 K (4 K.times.8 times) that is required for
returning these values, and the values obtained by left-shifting
7E80h (FF01h, FE02h, FC04h, F808h, F011h, E023h, C046h) are
used.
[0053] Here, diverse examples of scramblers adopting a random data
generator having a 64 K random data generation cycle, as shown in
FIG. 4, are disclosed in the Korean Patent Application No.
99-27886, filed by the present applicant on 10 Jul. 1999, under the
title of "Random Data Generator and a Scrambler Using the Random
Data Generator".
[0054] Referring to FIGS. 6 and 7, a generalized structure of a
scrambler shown in FIG. 4 and mentioned in the above application
will now be described in order to help explain the present
invention.
[0055] For example, a branch table 200, shown in FIG. 7, of a
scrambler shown in FIG. 6 stores the branch values B.sub.o0 through
B.sub.o15 for all possible cases when the number of effective
branches of the XOR gates G.sub.0 through G.sub.15 of a random data
generator is 4. The scrambler in FIG. 4 is implemented in a simple
structure in a case where the value of a branch is "B400h".
[0056] In FIG. 6, when any one value stored in the branch table 200
is selected, the multiplexors m.sub.0 through m.sub.15 receive the
16 output bits B.sub.o0 through B.sub.o15, respectively, according
to the selected branch value, as a selection signal. When values of
the outputs B.sub.o0 through B.sub.o15 of the branch table 200 are
"1", corresponding multiplexors of m.sub.0 through m.sub.15 supply
"0", which is input to the first input end (A), to one end of
corresponding XOR gates G.sub.0 through G.sub.15, as an output
signal Mo.sub.0 through Mo.sub.15. Corresponding XOR gates G.sub.0
through G.sub.15 output values of S.sub.0 through S.sub.15 of each
corresponding register r.sub.0 through r.sub.15 , which are input
to the other end of each XOR gate G.sub.0 through G.sub.15, without
change, and the accumulated output value of XOR gate G.sub.0 is
finally fed back and input to the least significant register
r.sub.0.
[0057] In addition, when values of the outputs B.sub.o0 through
B.sub.o15 of the branch table 200 are "0", corresponding
multiplexors of m.sub.0 through m.sub.15 supply the outputs So
through S.sub.15 of each register r.sub.0 through r.sub.15, which
is input to the second input end (B), as its own output signal
Mo.sub.0 through Mo.sub.15. Then, corresponding XOR gates of
G.sub.0 through G.sub.15 XOR S.sub.0 through S.sub.15, which is the
output of each multiplexor m.sub.0 through m.sub.15, and S.sub.0
through S.sub.15, which is the output of each register r.sub.0
through r.sub.15. At this time, since the outputs of corresponding
XOR gates G.sub.0 through G.sub.15 finally become "0", no feedback
value is input to the least significant register r.sub.0.
[0058] By doing so, 64 K random data from each register r.sub.0
through r.sub.15 are generated during one ECC block, and the result
D.sub.01 through D.sub.07 of scrambling by XORing 8 bits of input
data D.sub.0 through D.sub.7 and the outputs of the lower 8
registers r.sub.0 through r.sub.7, respectively, in XOR gates 201
through 208, respectively, is provided.
[0059] Here, if the number of registers is 16, the cycle of random
data becomes 2.sup.16 (=approximately 64 K), and if the number of
registers is n, the cycle of random data can be expanded to
2.sup.n.
[0060] The second structure of a scrambler according to the present
invention has the same structure as the scrambler shown in FIG. 4
or FIG. 6. As shown in FIG. 8, however, since its scrambling is
performed in units of the lower 8 bits of registers r.sub.0 through
r.sub.7 and 1 byte input data after left-shifting every one bit,
the initial values of registers r.sub.0 through r.sub.15, which are
determined by the upper 4 bits (ID(7:4)) of the last byte in a
4-byte identification code (ID), which is allocated to each sector,
are different from the initial values shown in FIG. 5. The initial
values in FIG. 8 are the initial values used in the scrambler of
FIG. 4.
[0061] That is, the first preset value 0001h and the values (3DADh,
D4E7h, FDCAh, EBCCh, 292Eh, 50Fh, 50F0h, BFCAh, 7F80h, D36Eh,
BB39h, 5DFFh, A809h, 6647h, 8044h, 0304h) of registers r.sub.0
through r.sub.15, which are obtained after each 4,096 times
left-shifting are used as the initial values, which is different
from the initial values of FIG. 5.
[0062] The second structure of a scrambler according to the present
invention has merit in that a serial structure as shown in FIG. 4
or FIG. 6 need not be changed into a parallel structure in response
to a need for high speed.
[0063] The third structure of a scrambler according to the present
invention is shown in FIG. 9. While the structure of the scramblers
in FIG. 4 and FIG. 6 have registers r.sub.0 through r.sub.15 for
generating random data having a 64 K cycle and perform scrambling
with changing initial values in each sector, the scrambler in FIG.
9 has 16 kinds of decoding values, each for generating random data
having a 4 K cycle, and changes the effective structure of a random
data generator according to the upper 4 bits (ID(7:4)) of the last
byte in a 4-byte identification code (ID) which is allocated to
each sector.
[0064] The scrambler of FIG. 9 has a random data generator having a
4.times.16 decoder 300, 12 multiplexors m.sub.0 through m.sub.11,
12 XOR gates G.sub.0 through G.sub.11, and 12 registers r.sub.0
through r.sub.11, and the scrambler further has XOR gates 301
through 308 for outputting the result D.sub.01 through D.sub.07 of
scrambling by XORing 8-bits of input data D.sub.0 through D.sub.7
and the outputs of the lower 8 registers r.sub.0 through r.sub.7,
respectively. Here, the 12 multiplexors can be collectively
referred to as a selection output circuit, which selectively
outputs "0" or the output of each register according to the 12-bit
output of the 4.times.16 decoder 300, and the 12 XOR gates G.sub.0
through G.sub.11 be referred to as a logic circuit, which supplies
the 12-bit result of XORing to the least significant register
r.sub.0.
[0065] When one of the control values (829h, 834h, 84Ch, 868h,
883h, 891h, 8B0h, 8C2h, 906h, 960h, 990h, A03h, A18h, B04h, C48h,
CA0h), as shown in FIG. 10, for controlling changes in the
structure of the 16 scrambler configurations (in the scrambler,
since the logical existence of each of the multiplexors M.sub.0
through M.sub.11, can be controlled by the bit values B.sub.0
through B.sub.11 input thereinto from the 4.times.16 decoder 300,
although the scrambler maintains the same physical structure, it
can be configured in 16 different ways) according to the upper 4
bits (ID(7:4)) of the last 1 byte in a 4-byte identification code
allocated to each sector is input every one ECC block, the
4.times.16 decoder 300 in FIG. 9 supplies a 12-bit output
corresponding to the control value, and among the 12-bit output
Bo.sub.0 through Bo.sub.11, only those branches which have "1" are
effective. The 4.times.16 decoder can output 16 kinds of decoding
values according to its 4-bit inputs. Here, the initial values of
registers r.sub.0 through r.sub.11 are set in units of one ECC
block, and, for example, the initial values are set to "001h".
[0066] The multiplexors m.sub.0 through m.sub.11 receive the 12
output bits B.sub.o0 through B.sub.o11 as a selection signal, and
when values of the outputs Bo.sub.0 through B.sub.011 of the
4.times.16 decoder 300 are "1", corresponding multiplexors m.sub.0
through m.sub.11, supply "0", which is input to the first input end
(A), to one end of corresponding XOR gates of G.sub.0 through
G.sub.11, as an output signal Mo.sub.0 through Mo.sub.11.
Corresponding XOR gates of G.sub.0 through G.sub.11 output values
of S.sub.0 through S.sub.11 of each corresponding register r.sub.0
through r.sub.11, which are input to the other end of each XOR gate
G.sub.0 through G.sub.15, without change, and the accumulated
output value of XOR gate G.sub.0 is fed back and input to the least
significant register r.sub.0.
[0067] In addition, when values of the outputs B.sub.o0 through
B.sub.o11 of the 4.times.16 decoder 300 are "0", corresponding
multiplexors of m.sub.0 through m.sub.11 supply the outputs S.sub.0
through S.sub.11 of each corresponding register r.sub.0 through
r.sub.11, which is input to the second input end of the second
input end (B), as its own output signal Mo.sub.0 through Mo.sub.11.
Then, corresponding XOR gates of G.sub.0 through G.sub.11 XOR
S.sub.0 through S.sub.11, which are the output of each multiplexor
m.sub.0 through m.sub.11, and S.sub.0 through S.sub.11, which are
the output of the corresponding registers r.sub.0 through r.sub.11.
At this time, since the output of the corresponding XOR gates
G.sub.0 through G.sub.11 finally become "0", no feedback value is
input to the least significant register r.sub.0.
[0068] By doing so, 4K of random data from each register r.sub.0
through r.sub.11 are generated in units of a sector, and the result
D.sub.01 through D.sub.07 of scrambling by XORing 1 byte of input
data D.sub.0 through D.sub.7 and each output of the lower 8
registers r.sub.0 through r.sub.7 in XOR gates 301 through 308 is
provided.
[0069] Thus, the structure of a scrambler can be changed depending
on the capacity of the innermost circumference track, the capacity
of the outermost circumference track, the size of a sector and the
size of an ECC block. That is, a system using an HD-DVD, in which
the sector size is 2KB and the ECC block size is 32 sectors, can
use the scrambler which is used in a general DVD system, without
change. Meanwhile, a system using an HD-DVD, in which the sector
size is 4 KB and the ECC block size is 16 sectors, can use one of
the three types below.
[0070] N) scrambled data is output when a random generator performs
an 8-bit shift: FIG. 4 (FIG. 6)+FIG. 5;
[0071] Ii) scrambled data is output when a random data generator
performs a 1-bit shift: FIG. 4 (FIG. 6)+FIG. 8; or
[0072] Iii) a random data generator whose structure can be changed
according to the decoding values: FIG. 9+FIG. 10.
[0073] In the meantime, the conditions for the random data
generation cycle of a random data generator used in a scrambler for
an optical disc system will now be explained.
[0074] When it is assumed that a first data frame (Data Frame 1) is
a sector, a second data frame (Data Frame 2) is an ECC block, the
data amount in the first data frame is b, the data amount in the
second data frame is B, the data amount in the innermost
circumference track is A, and the data amount of two tracks in the
outermost circumference is C, the following condition 1, condition
2, and condition 3 must be met, and the random data generation
cycle of the random data generator in a scrambler of an optical
system must be equal to or greater than B. The same values from the
random data generator or the same decoding values can be used while
the random data generator does not exceed .alpha..times./B.
Data Frame 2=n.times.Data Frame 1, n is an integer Condition 1
.vertline.A/B.vertline.=.alpha., .vertline.A/B.vertline. represents
the integer part of A/B. Condition 2
b.times.C/B=B. Condition 3
EXAMPLE 1
[0075] A General DVD
[0076] When Data Frame 1=2K (b), Data Frame 2=32K (B), and the data
amount of two tracks in the outermost circumference=284 K (C), a
random data generation cycle must be equal to or greater than 17.75
K (=2 K.times.284/32 K), and the random data generation cycle of a
scrambler in an actual DVD is 32K. .vertline.A/B.vertline.=int
.vertline.60K/32K.vertl- ine.=.alpha.=1, .alpha..times.B=32K.
Therefore, it is possible to use an initial value or a decoding
value which the random data generator cycle does not exceed
32K.
EXAMPLE 2
[0077] The first case of an HD-DVD having a line density in a
tangential direction twice as high as that of a DVD
[0078] When Data Frame 1=4 K (b), Data Frame 2=64 K (B), and the
data amount of two tracks in the outermost circumference=568 K (C),
a random data generation cycle must be equal to or greater than
35.5 K (=4 K.times.568/64 K). Since .alpha.=int
.vertline.120K/64K.vertline.=1, it is possible to use an initial
value or a decoding value while the random data generation cycle
does not exceed 64K.
EXAMPLE 3
[0079] The second case of an HD-DVD having a line density in a
tangential direction twice as high as that of a DVD
[0080] When Data Frame 1=8 K (b), Data Frame 2=64 K (B), and the
data amount of two tracks in the outermost circumference=568 K (C),
a random data generation cycle must be equal to or greater than 71
K (=8 K.times.568/64 K). Since .alpha.=int
.vertline.120K/64K.vertline.=1, it is possible to use an initial
value or a decoding value while the random data generation cycle
does not exceed 64K.
EXAMPLE 4
[0081] The third case of an HD-DVD having a line density in a
tangential direction twice as high as that of a DVD
[0082] When Data Frame 1=2 K (b), Data Frame 2=64 K (B), and the
data amount of two tracks in the outermost circumference=568 K (C),
a random data generation cycle must be equal to or greater than
17.75 K (=4 K.times.568/64 K), and the scrambler of a general DVD
system can be used. Since .alpha.=int
.vertline.120K/64K.vertline.=1, it is possible to use an initial
value or a decoding value while the random data generation cycle
does not exceed 64K.
[0083] The present invention can be used in equipment using data
scrambling, and particularly, can be efficiently used in a high
density disc system.
[0084] The scrambling method of the scrambler according to the
present invention is advantageous in generating a stable servo
signal and suppressing the DC component in modulation in high
density optical recording/reproducing apparatuses. In addition,
since the scrambler can generate random data having a long cycle of
equal to or greater than 64 K, it can be applied to an HD-DVD
system.
[0085] Although a few preferred embodiments of the present
invention have been shown and described, it would be appreciated by
those skilled in the art that changes may be made in this
embodiment without departing from the principles and spirit of the
invention, the scope of which is defined in the claims and their
equivalents.
* * * * *