U.S. patent application number 12/836571 was filed with the patent office on 2010-11-04 for systems for obtaining write strategy parameters utilizing data-to-clock edge deviations, and related method and optical storage device thereof.
Invention is credited to Chih-Hsiung Chu, Yuan-Chin Liu, CHIH-CHING YU.
Application Number | 20100278023 12/836571 |
Document ID | / |
Family ID | 37425367 |
Filed Date | 2010-11-04 |
United States Patent
Application |
20100278023 |
Kind Code |
A1 |
YU; CHIH-CHING ; et
al. |
November 4, 2010 |
SYSTEMS FOR OBTAINING WRITE STRATEGY PARAMETERS UTILIZING
DATA-TO-CLOCK EDGE DEVIATIONS, AND RELATED METHOD AND OPTICAL
STORAGE DEVICE THEREOF
Abstract
A system in an optical storage device has a controller which
obtains a plurality of write strategy parameters for the optical
storage device to write data on an optical storage medium. The
write strategy parameters are derived from data-to-clock edge
deviations respectively corresponding to a plurality of data set
types. Each of the data set types corresponds to a combination of
at least a specific target pit length and a specific target land
length, or a combination of at least a specific target land length
and a specific target pit length.
Inventors: |
YU; CHIH-CHING; (Tao-Yuan
Hsien, TW) ; Liu; Yuan-Chin; (Hsin-Chu City, TW)
; Chu; Chih-Hsiung; (Taipei Hsien, TW) |
Correspondence
Address: |
NORTH AMERICA INTELLECTUAL PROPERTY CORPORATION
P.O. BOX 506
MERRIFIELD
VA
22116
US
|
Family ID: |
37425367 |
Appl. No.: |
12/836571 |
Filed: |
July 14, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10908580 |
May 18, 2005 |
7778122 |
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12836571 |
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Current U.S.
Class: |
369/47.15 ;
G9B/20 |
Current CPC
Class: |
G11B 7/1267 20130101;
G11B 7/00456 20130101 |
Class at
Publication: |
369/47.15 ;
G9B/20 |
International
Class: |
G11B 20/00 20060101
G11B020/00 |
Claims
1. A system in an optical storage device, comprising: a controller,
obtaining a plurality of write strategy parameters for the optical
storage device to write data on an optical storage medium, wherein
the write strategy parameters are derived from data-to-clock edge
deviations respectively corresponding to a plurality of data set
types, and each of the data set types corresponds to a combination
of at least a specific target pit length and a specific target land
length, or a combination of at least a specific target land length
and a specific target pit length.
2. The system of claim 1, further comprising: a detector for
detecting a plurality of lengths according to a reproduced signal
generated by the optical storage device accessing the optical
storage medium, and each length corresponding to a pit or a
land.
3. The system of claim 2, further comprising: a slicer for slicing
the reproduced signal to generate a sliced signal; wherein the
detector detects intervals between rising edges and falling edges
of the sliced signal and/or intervals between falling edges and
rising edges of the sliced signal as the lengths, and each interval
corresponds to a pit or a land.
4. The system of claim 3, further comprising: a calculation module
for calculating a plurality of data-to-clock edge lengths and a
plurality of differences to generate the data-to-clock edge
deviations respectively corresponding to the data set types,
wherein each data-to-clock edge length is an interval between a
rising or falling edge of a first reference clock and a rising or
falling edge of the sliced signal, and each difference is a
difference between a data-to-clock edge length and a target
data-to-clock edge length, wherein the target data-to-clock edge
length is a predetermined value corresponds to a specific data set
type or an average of a plurality of data-to-clock edge lengths
corresponding to a specific data set type.
5. The system of claim 4, further comprising: a phase-locked loop
(PLL) for generating the first reference clock according to the
sliced signal; wherein the detector and the calculation module are
coupled to the PLL, and the detector detects the lengths according
to the first reference clock.
6. The system of claim 4, further comprising: a phase-locked loop
(PLL) for generating the first reference clock according to the
sliced signal; and an oscillator for generating a second reference
clock; wherein the detector is coupled to the oscillator and
detects the lengths according to the second reference clock, and
the calculation module is coupled to the PLL.
7. The system of claim 2, further comprising: a sampling circuit
for sampling the reproduced signal to generate a digital signal;
wherein the detector is coupled to the sampling circuit and detects
intervals between time points when the value of the digital signal
crosses a predetermined value to generate the lengths, and each
interval corresponds to a pit or a land.
8. The system of claim 7, wherein the sampling circuit further
comprises: an analog-to-digital converter (ADC) for performing
analog-to-digital conversion on the reproduced signal according to
a reference clock to generate the digital signal; and a
phase-locked loop (PLL) coupled to the ADC for generating the
reference clock according to the digital signal.
9. The system of claim 7, wherein the sampling circuit further
comprises: an analog-to-digital converter (ADC) for performing
analog-to-digital conversion on the reproduced signal; an
interpolator coupled to the ADC for performing an interpolation
operation according to a reference clock and results generated by
the ADC to generate the digital signal; and a phase-locked loop
(PLL) coupled to the interpolator for generating the reference
clock according to the digital signal.
10. The system of claim 1, further comprising: a calculation
module, comprising: a pattern dependency classifier for classifying
a plurality of data sets into the data set types, each data set
comprising lengths corresponding to a pit and an adjacent land or
lengths corresponding to a land and an adjacent pit, respectively;
and a data-to-clock edge deviation calculator coupled to the
pattern dependency classifier for calculating the data-to-clock
edge deviations respectively corresponding to the data set
types.
11. A system in an optical storage device, comprising: a detector,
capable of configuring to detect a plurality of lengths, each
length corresponding to a pit or a land on an optical storage
medium accessed by the optical storage device; a calculation
module, capable of configuring to perform calculations
corresponding to a plurality of data set types and generate a
plurality of data-to-clock edge deviations respectively
corresponding to the data set types, wherein each of the data set
types corresponds to a combination of at least a specific target
pit length and a specific target land length, or a combination of
at least a specific target land length and a specific target pit
length; and a controller, capable of configuring to calibrate a
plurality of write strategy parameters respectively corresponding
to the data set types utilizing the data-to-clock edge deviations,
wherein the write strategy parameters are utilized to write data on
the optical storage medium.
12. A method for obtaining write strategy parameters for an optical
storage device, comprising: writing data on optical storage medium;
reading data written on the optical storage medium to generate a
reproduced signal; detecting a plurality of lengths from the
reproduced signal, each length corresponding to a pit or a land on
the optical storage medium; performing calculations corresponding
to a plurality of data set types and generating a plurality of
data-to-clock edge deviations respectively corresponding to the
data set types, wherein each of the data set types corresponds to a
combination of at least a specific target pit length and a specific
target land length, or a combination of at least a specific target
land length and a specific target pit length; and obtaining the
write strategy parameters respectively corresponding to the data
set types utilizing the data-to-clock edge deviations.
13. The method of claim 12, wherein the step of detecting the
lengths further comprises: slicing the reproduced signal to
generate a sliced signal; and detecting intervals between rising
edges and falling edges of the sliced signal and/or intervals
between falling edges and rising edges of the sliced signal as the
lengths, wherein each interval corresponds to a pit or a land.
14. The method of claim 13, wherein the step of performing
calculations corresponding to the data set types and generating the
data-to-clock edge deviations respectively corresponding to the
data set types further comprises: calculating a plurality of
data-to-clock edge lengths, each data-to-clock edge length being an
interval between a rising or falling edge of a first reference
clock and a rising or falling edge of the sliced signal; and
calculating a plurality of differences to generate the
data-to-clock edge deviations respectively corresponding to the
data set types, each difference being a difference between a
data-to-clock edge length and a target data-to-clock edge length,
wherein the target data-to-clock edge length is a predetermined
value corresponding to a specific data set type or an average of a
plurality of data-to-clock edge lengths corresponding to a specific
data set type.
15. The method of claim 14, further comprising: generating the
first reference clock according to the sliced signal.
16. The method of claim 15, wherein the step of generating the
first reference clock according to the sliced signal further
comprises generating the first reference clock utilizing a
phase-locked loop (PLL), and the step of detecting the lengths
further comprises: detecting the lengths according to the first
reference clock.
17. The method of claim 15, wherein the step of generating the
first reference clock according to the sliced signal further
comprises generating the first reference clock utilizing a
phase-locked loop (PLL), and the step of detecting the lengths
further comprises: generating a second reference clock utilizing an
oscillator; and detecting the lengths according to the second
reference clock.
18. The method of claim 12, wherein the step of detecting the
lengths further comprises: sampling the reproduced signal to
generate a digital signal; and detecting intervals between time
points when the value of the digital signal crosses a predetermined
value to generate the lengths, wherein each interval corresponds to
a pit or a land.
19. The method of claim 18, wherein the step of performing
calculations corresponding to the data set types and generating the
data-to-clock edge deviations respectively corresponding to the
data set types further comprises: calculating differences between
the value of the digital signal and the predetermined value around
the time points when the value of the digital signal crosses the
predetermined value to generate the data-to-clock edge
deviations.
20. The method of claim 18, wherein the step of sampling the
reproduced signal further comprises: performing analog-to-digital
conversion on the reproduced signal according to a reference clock
to generate the digital signal; and generating the reference clock
according to the digital signal utilizing a phase-locked loop
(PLL).
21. The method of claim 12, wherein the step of performing
calculations corresponding to the data set types and generating the
data-to-clock edge deviations respectively corresponding to the
data set types further comprises: classifying a plurality of data
sets into the data set types, each data set comprising lengths
corresponding to a pit and an adjacent land or lengths
corresponding to a land and an adjacent pit, respectively; and
calculating the data-to-clock edge deviations respectively
corresponding to the data set types.
22. The method of claim 12, wherein in the step of performing
calculations corresponding to the data set types and generating the
data-to-clock edge deviations respectively corresponding to the
data set types, each of the data set types corresponds to a
combination of at least a specific target pit length and specific
target land lengths, or a combination of at least a specific target
land length and specific target pit lengths, or a combination of
specific target land lengths and specific target pit lengths.
23. An optical storage device, writing data on an optical storage
medium utilizing a plurality of write strategy parameters obtained
by the method claimed in claim 12.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This continuation application claims the benefit of
co-pending U.S. patent application Ser. No. 10/908,580, filed on
May 18, 2005 and incorporated herein by reference.
BACKGROUND
[0002] The present invention relates to write strategy tuning of an
optical storage device, and more particularly, to systems for
obtaining write strategy parameters utilizing data-to-clock edge
deviations, and related method and optical storage device
thereof.
[0003] As multimedia applications continue to progress, the demand
for storing massive digital data increases rapidly. As a result,
high storage volume and compact size optical storage media such as
Compact Discs (CDs) or Digital Versatile Discs (DVDs) are very
popular, and optical storage devices such as CD drives or DVD
drives have become standard accessories of personal computers,
utilized for performing the multimedia applications.
[0004] Take the CD drive as an example. When the CD drive is
controlled to write data to a CD-Recordable (CD-R) disc, the
writing power of a laser diode in the CD drive is usually set to be
a specific value, and write pulses corresponding to the data are
utilized for recording pits and lands onto the grooves of the CD-R
disc. The specific value of the writing power can be derived from
an optimal power calibration (OPC) process. On the other hand,
through a write strategy tuning process, which is also referred to
as a recording strategy tuning process, changing write strategy
parameters for controlling widths of the write pulses may increase
the accuracy of lengths of pits and lands formed on the CD-R disc.
Please refer to related documents of the CD-R specifications (e.g.
the Orange Book Part I) for more information.
[0005] According to the related art, a specific device such as an
oscilloscope can be utilized during the write strategy tuning
process. Usually, according to an eye pattern of a plurality of
reproduced waveforms shown on the oscilloscope after a trial
writing process in advance, a new set of write strategy parameters
for controlling the widths of the write pulses are determined,
based on experience, by an engineer or researcher. It takes a lot
of engineer or researcher's time to utilize this method because the
same process must be repeatedly performed for various applicable
media and different recording speeds, including at least writing
test data, inspecting an eye pattern of reproduced waveforms shown
on the oscilloscope, and determining a new set of write strategy
parameters by experience according to the eye pattern. The write
strategy tuning process mentioned above is time consuming since
determining the write strategy parameters by inspecting eye
patterns is not an automatic operation. In addition, the write
strategy tuning process mentioned above is indefinite since
determining a new set of write strategy parameters by experience
according to the eye pattern is not quantitative. Under certain
situations, an unclear eye pattern would invalidate or interfere
with the write strategy tuning process.
[0006] A specific instrument such as a time interval analyzer (TIA)
or a jitter meter might be helpful for the purpose of deriving
information for determining a new set of write strategy parameters.
However, similar routine work is also required, and if the TIA or
jitter meter is simply coupled for measuring without setting up an
additional control system, the same drawbacks caused by the manual
tuning process still existed. In addition, the information derived
from the specific instrument is usually implicit and therefore
takes up a large amount of experienced engineer or researcher's
time.
SUMMARY
[0007] It is one of the objectives of the claimed invention to
provide systems for obtaining write strategy parameters utilizing
data-to-clock edge deviations, and related method and optical
storage device thereof.
[0008] According to a first aspect of the present invention, an
exemplary system in an optical storage device is disclosed. The
exemplary system includes a controller which obtains a plurality of
write strategy parameters for the optical storage device to write
data on an optical storage medium. The write strategy parameters
are derived from data-to-clock edge deviations respectively
corresponding to a plurality of data set types. Each of the data
set types corresponds to a combination of at least a specific
target pit length and a specific target land length, or a
combination of at least a specific target land length and a
specific target pit length.
[0009] According to a second aspect of the present invention, an
exemplary system in an optical storage device is disclosed. The
exemplary system includes a detector, a calculation module, and a
controller. The detector is capable of configuring to detect a
plurality of lengths, each length corresponding to a pit or a land
on an optical storage medium accessed by the optical storage
device. The calculation module is capable of configuring to perform
calculations corresponding to a plurality of data set types and
generate a plurality of data-to-clock edge deviations respectively
corresponding to the data set types, wherein each of the data set
types corresponds to a combination of at least a specific target
pit length and a specific target land length, or a combination of
at least a specific target land length and a specific target pit
length. The controller is capable of configuring to calibrate a
plurality of write strategy parameters respectively corresponding
to the data set types utilizing the data-to-clock edge deviations,
wherein the write strategy parameters are utilized to write data on
the optical storage medium.
[0010] According to a third aspect of the present invention, an
exemplary method for obtaining write strategy parameters for an
optical storage device is disclosed. The exemplary method includes
the following steps: writing data on optical storage medium;
reading data written on the optical storage medium to generate a
reproduced signal; detecting a plurality of lengths from the
reproduced signal, each length corresponding to a pit or a land on
the optical storage medium; performing calculations corresponding
to a plurality of data set types and generating a plurality of
data-to-clock edge deviations respectively corresponding to the
data set types, wherein each of the data set types corresponds to a
combination of at least a specific target pit length and a specific
target land length, or a combination of at least a specific target
land length and a specific target pit length; and obtaining the
write strategy parameters respectively corresponding to the data
set types utilizing the data-to-clock edge deviations.
[0011] According to a fourth aspect of the present invention, an
exemplary optical storage device which writes data on an optical
storage medium utilizing a plurality of write strategy parameters
obtained by the above-mentioned exemplary method is disclosed.
[0012] These and other objectives of the present invention will no
doubt become obvious to those of ordinary skill in the art after
reading the following detailed description of the preferred
embodiment that is illustrated in the various figures and
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a block diagram of a system for tuning write
strategy parameters of an optical storage device according to one
embodiment of the present invention.
[0014] FIG. 2 is a length compensation illustration utilizing
data-to-clock edge deviations according to one embodiment of the
present invention.
[0015] FIG. 3 is a flowchart of a method for tuning write strategy
parameters according to one embodiment of the present
invention.
[0016] FIG. 4 is a table illustrating data set types corresponding
to target length combinations according to one embodiment of the
present invention.
[0017] FIG. 5 is a block diagram of a system for tuning write
strategy parameters of an optical storage device according to one
embodiment of the present invention.
[0018] FIG. 6 is a block diagram of a system for tuning write
strategy parameters of an optical storage device according to one
embodiment of the present invention.
[0019] FIG. 7 illustrates sample points on a reproduced signal with
respect to an EFM data clock, where a difference between a specific
sample point's value and a predetermined value is utilized for
representing a data-to-clock edge deviation according to one
embodiment of the present invention.
[0020] FIG. 8 illustrates a variation of the embodiment shown in
FIG. 6.
DETAILED DESCRIPTION
[0021] The present invention provides systems for tuning a
plurality of write strategy parameters of an optical storage
device. According to a first aspect, one of the systems is a
circuit for tuning the write strategy parameters, where the circuit
is positioned in the optical storage device. According to a second
aspect, one of the systems is substantially the optical storage
device itself. For simplicity, the first aspect is utilized in the
following description. However, the second aspect is also
applicable to the detailed embodiments.
[0022] FIG. 1 illustrates a block diagram of a system 100C for
tuning a plurality of write strategy parameters of an optical
storage device 100 according to a first embodiment, where the
system 100C is a circuit positioned in the optical storage device
100 accessing an optical storage medium 102. Please note that for
simplicity, this embodiment is described utilizing a CD-R disc as
the optical storage medium 102 and utilizing a CD drive as the
optical storage device 100. Those skilled in the art should
understand that other kinds of optical storage media such as a
DVD-R disc, a DVD+R disc, or a DVD-RAM disc, and corresponding
optical storage devices such as a DVD drive are applicable
according to other embodiments of the present invention.
[0023] As shown in FIG. 1, an optical pickup 110 of the optical
storage device 100 reads data from the optical storage medium 102
to generate a raw radio frequency (RF) signal 111 in a reading mode
of the optical storage device 100. A waveform equalizer 112 of the
optical storage device 100 equalizes the raw RF signal 111 to
generate a reproduced signal, which is the RF signal 113 in the
first embodiment. In addition, a slicer 114 of the optical storage
device 100 slices the RF signal 113 to generate a sliced signal
115. Operation principles of the optical pickup 110, the waveform
equalizer 112, and the slicer 114 are well known in the art and
therefore not described in detail here.
[0024] Within the optical storage device 100 shown in FIG. 1, a
modulator 160, a write pulse generator 162, and a radiation source
driver 164 co-operate to drive the optical pickup 110 according to
the write strategy parameters, which is tuned by the system 100C
through a control signal 151 according to the sliced signal 115.
The modulator 160 is coupled to an encoder (not shown) of the
optical storage device 100 for modulating encoded data outputted by
the encoder to generate a modulated signal 161 carrying
eight-to-fourteen modulation (EFM) information. The write pulse
generator 162 generates write pulses corresponding to the EFM
information carried by the modulated signal 161 according to the
write strategy parameters mentioned above, and outputs the write
pulses carried by a write pulse signal 163. In addition, the
radiation source driver 164 generates a driving signal 165
according to the write pulse signal 163 to drive the optical pickup
110. Operation principles of the modulator 160, the write pulse
generator 162, and the radiation source driver 164 are well known
in the art and therefore not described in detail here.
[0025] According to this embodiment, the system 100C comprises a
phase-locked loop (PLL) 120, a detector such as an EFM length
detector 130 shown in FIG. 1, a calculation module 140, and a
controller such as a write pulse controller 150 shown in FIG. 1,
where the calculation module 140 comprises a pattern dependency
classifier 142 and a data-to-clock edge deviation calculator 144.
The PLL 120 generates an EFM data clock CLK according to the sliced
signal 115 by locking the channel bit rate (1/T) of the sliced
signal 115, where the period of the EFM data clock CLK is
considered to be 1 T. The EFM length detector 130 derives EFM
information carried by the sliced signal 115 according to the EFM
data clock CLK, and detects a plurality of lengths, where each
length corresponds to a pit or a land recorded on the optical
storage medium 102. The sliced signal 115 is typically a square
wave having various intervals between rising edges and falling
edges thereof and various intervals between falling edges and
rising edges thereof. In this embodiment, the EFM length detector
130 measures intervals between rising edges and falling edges of
the sliced signal 115 and/or intervals between falling edges and
rising edges of the sliced signal 115 as the lengths mentioned
above, where each interval corresponds to a pit or a land. As a
result, the lengths comprise pit lengths P corresponding to pits,
and land lengths L corresponding to lands. Each of the pit lengths
P represents a pit recorded along a groove on the optical storage
medium 102, and each of the land lengths L represents a land along
the groove. Please note that the sliced signal 115 of another
embodiment of the present invention may carry EFM plus (EFM+)
information (e.g. for an embodiment of DVD-R) or other information
complying with a variation of the EFM/EFM+ specification.
[0026] In the first embodiment, the pit lengths and the land
lengths derived from the sliced signal 115 are multiples of clock
period T and ranging from 3 T to 11 T in an ideal case of the CD-R
disc. That is, a length P of a pit or a length L of a land can be 3
T, 4 T, . . . , or 11 T. So it is reasonable that a reference
signal for measuring the lengths of the pits and the lands (e.g.
the EFM data clock CLK) has a period less than or equal to T.
According to this embodiment, the reference signal inputted into
the EFM length detector 130 is the EFM data clock CLK, so the
period of the reference clock is T. In a real case of the CD-R
disc, the lengths L and P carried by the output signal 131 of the
EFM length detector 130 are usually not exact multiples of T. The
calculation module 140 may perform calculations corresponding to a
plurality of data set types and generate a plurality of
data-to-clock edge deviations respectively corresponding to the
data set types, where the data-to-clock edge deviations are carried
by an output signal 145 of the data-to-clock edge deviation
calculator 144. Each of the data set types corresponds to a
combination of at least a specific target pit length (e.g. 3 T, 4
T, . . . , 11 T) and a specific target land length (e.g. 3 T, 4 T,
. . . , 11 T) or a combination of at least a specific target land
length and a specific target pit length.
[0027] The pattern dependency classifier 142 classifies a plurality
of data sets into the data set types. In this embodiment, each data
set, being (P, L) or (L, P), comprises two lengths, where a data
set (P, L) means one length corresponds to a pit and another
corresponds to an adjacent land, and a data set (L, P) means one
length corresponds to a land and another corresponds to an adjacent
pit. Here, notation such as (P.sub.nT, L.sub.mT) or (L.sub.nT,
P.sub.mT) is utilized for denoting the data set types mentioned
above, where nT or mT indicates the length in terms of the clock
period T, n=3, 4, . . . , 11 and m=3, 4, . . . , 11 in this
embodiment. Each of the data set types (L.sub.nT, P.sub.mT), e.g. a
data set type (L.sub.n0*T, P.sub.m0*T) having n=n0 and m=m0, is
utilized for classifying data sets (L, P) corresponding to a land
having a target land length of n0*T followed by an adjacent pit
having a target pit length of m0*T. Similarly, each of the data set
types (P.sub.nT, L.sub.mT), e.g. a data set type (P.sub.n0*T,
L.sub.m0*T) having n=n0 and m=m0, is utilized for classifying data
sets (P, L) corresponding to a pit having a target pit length of
n0*T followed by an adjacent land having a target land length of
m0*T. It is noted that each of the data set types (L.sub.nT,
P.sub.mT), e.g. the data set type (L.sub.n0*T, P.sub.m0*T),
corresponds to a combination (n0*T, m0*T) of a specific target land
length n0*T and a specific target pit length m0*T, and each of the
data set types (P.sub.nT, L.sub.mT), e.g. the data set type
(P.sub.n0*T, L.sub.m0*T), corresponds to a combination (n0*T, m0*T)
of a specific target pit length n0*T and a specific target land
length m0*T. There are 9 possible values for n and m, so there are
9*9 combinations for each of the data set types (L.sub.nT,
P.sub.mT) and (P.sub.nT, L.sub.mT), and the total number of data
set types would be 9*9*2=162.
[0028] In addition, the pattern dependency classifier 142 may
classify the data sets (L, P) as data set type (L.sub.n0*T,
P.sub.m0*T) if the lengths L and P satisfy:
(n0-0.5)*T.ltoreq.L.ltoreq.(n0+0.5)*T and
(m0-0.5)*T.ltoreq.P.ltoreq.(m0+0.5)*T.
[0029] Similarly, the pattern dependency classifier 142 may
classify the data sets (P, L) as data set type (P.sub.n0*T,
L.sub.m0*T) if the lengths P and L satisfy:
(n0-0.5)*T.ltoreq.P.ltoreq.(n0+0.5)*T and
(m0-0.5)*T.ltoreq.L.ltoreq.(m0+0.5)*T.
[0030] The data-to-clock edge deviation calculator 144 may
calculate the data-to-clock edge deviations respectively
corresponding to the data set types (L.sub.nT, P.sub.mT) and
(P.sub.nT, L.sub.mT) as follows. The data-to-clock edge deviation
calculator 144 calculates a plurality of data-to-clock edge
lengths, where each data-to-clock edge length is an interval
between a rising/falling edge of the reference clock mentioned
above (i.e. the EFM data clock CLK in this embodiment) and a
transition edge of the sliced signal 115. Additionally, the
data-to-clock edge deviation calculator 144 calculates a plurality
of differences to generate the data-to-clock edge deviations
respectively corresponding to the data set types (L.sub.nT,
P.sub.mT) and (P.sub.nT, L.sub.mT). Each of the differences
mentioned above is a difference between a data-to-clock edge length
and a target data-to-clock edge length that is a predetermined
value corresponding to a specific data set type (L.sub.n0*T,
P.sub.m0*T) or (P.sub.n0*T, L.sub.m0*T).
[0031] Take the situation shown in FIG. 2 as an example. FIG. 2 is
a length compensation illustration utilizing the data-to-clock edge
deviations according to the first embodiment, where two pits A and
B both corresponding to a target length P.sub.4T (i.e. the target
length of 4 T-pit) and a land corresponding to a target length
L.sub.5T (i.e. the target length of 5 T-land) are illustrated. As
shown in FIG. 2, Ttopr and Tlast respectively denote write strategy
parameters for controlling the beginning location and the end
location of pits. According to this embodiment, the write strategy
parameters Ttopr(n, m) represent the write strategy parameters for
controlling the beginning location of the pits corresponding to the
data set types (L.sub.nT, P.sub.mT), and the write strategy
parameters Tlast(n, m) represent the write strategy parameters for
controlling the end location of the pits corresponding to the data
set types (P.sub.nT, L.sub.mT). Here, pit A and the adjacent land
following thereof (i.e. the 5 T-land between pits A and B)
correspond to a data set type (P.sub.4T, L.sub.5T), and this 5
T-land and pit B correspond to a data set type (L.sub.5T,
P.sub.4T). In addition, the write strategy parameter Tlast
corresponding to the end location of pit A is referred to as
Tlast(4, 5), and the write strategy parameter Ttopr corresponding
to the beginning location of pit B is referred to as Ttopr(5,
4).
[0032] The data-to-clock edge deviation calculator 144 calculates a
data-to-clock edge length d1. In this embodiments, the
data-to-clock edge length d1 is an interval between time point D of
a falling edge of the sliced signal 115, i.e. the time point
corresponding to the end location of pit A, and a subsequent rising
edge of the EFM data clock CLK, e.g. time point d. Please note that
time point D is substantially the same time point as when the value
of the RF signal 113 crosses the predetermined value such as the
value corresponding to the slicing level of the slicer 114. The
data-to-clock edge deviation calculator 144 detects time point D by
detecting the transition of the sliced signal 115 from high to low.
Same method can be applied to calculate each of the data-to-clock
edge lengths corresponding to data set type (P.sub.4T, L.sub.5T).
Additionally, the data-to-clock edge deviation calculator 144
calculates a plurality of differences to generate data-to-clock
edge deviations corresponding to the data set types. In some
embodiments, the data-to-clock edge deviation calculator 144
generates the data-to-clock edge deviation of a particular data set
type by conducting statistics analysis on the differences
corresponding to the data set type. The statistics analysis may be
averaging the difference, or finding the most frequent value of the
differences. Each of the differences mentioned above is a
difference between a data-to-clock edge length and a target
data-to-clock edge length, for example, 0.5 T in this embodiment.
The target data-to-clock edge length corresponding to data set
types (P.sub.4T, L.sub.5T) is 0.5 T because the time point
corresponding to the end location of pit A in an ideal case is
supposed to be time point Do.
[0033] Similarly, the data-to-clock edge deviation calculator 144
calculates a data-to-clock edge length d2, which is an interval
between time point E of a rising edge of the sliced signal 115,
i.e. the time point corresponding to the beginning location of pit
B and a subsequent rising edge of the EFM data clock CLK, e.g. time
point e. Please note that time point E is substantially the same
time point as when the value of the RF signal 113 crosses the
predetermined value such as the value corresponding to the slicing
level of the slicer 114. The data-to-clock edge deviation
calculator 144 detects time point E by detecting transition of the
sliced signal 115 from low to high. Same method can be applied to
calculate the data-to-clock edge lengths corresponding to data set
type (L.sub.5T, P.sub.4T). Additionally, the data-to-clock edge
deviation calculator 144 calculates a plurality of differences to
generate data-to-clock edge deviations corresponding to the data
set types, where each of the differences mentioned above is a
difference between a data-to-clock edge length and a target
data-to-clock edge length. In this embodiment, the target
data-to-clock edge length corresponding to data set type (L.sub.5T,
P.sub.4T) is determined to be 0.5 T because the time point
corresponding to the beginning location of pit B in an ideal case
is supposed to be time point Eo.
[0034] It is noted that the classification information generated by
the pattern dependency classifier 142 can be sent to the write
pulse controller 150 through the data-to-clock edge deviation
calculator 144 if needed since the transmission from the
data-to-clock edge deviation calculator 144 to the write pulse
controller 150 is digital. Similarly, the detection result(s)
generated by the EFM length detector 130 can be sent to the
data-to-clock edge deviation calculator 144 through the pattern
dependency classifier 142 if needed since the transmission from the
pattern dependency classifier 142 to the data-to-clock edge
deviation calculator 144 is digital. In a variation of the first
embodiment, the write pulse controller 150 can be coupled to the
pattern dependency classifier 142 through direct connection, and
the data-to-clock edge deviation calculator 144 can also be coupled
to the EFM length detector 130 through direct connection.
[0035] In a variation of the first embodiment, the target
data-to-clock edge length utilized for calculating the differences
to generate the data-to-clock edge deviations corresponding to a
specific data set type (L.sub.n0*T, P.sub.m0*T) can be an average
of a plurality of data-to-clock edge lengths corresponding to the
specific data set type (L.sub.n0*T, P.sub.m0*T). Similarly, the
target data-to-clock edge length utilized for calculating the
differences to generate the data-to-clock edge deviations
corresponding to a specific data set type (P.sub.n0*T, L.sub.m0*T)
can be an average of a plurality of data-to-clock edge lengths
corresponding to the specific data set type (P.sub.n0*T,
L.sub.m0*T). In another variation of the first embodiment, the
target data-to-clock edge length utilized for calculating the
differences to generate the data-to-clock edge deviations
corresponding to a specific data set type (L.sub.n0*T, P.sub.m0*T)
or (P.sub.n0*T, L.sub.m0*T) can be an average of a plurality of
data-to-clock edge lengths corresponding to the specific data set
type (L.sub.n0*T, P.sub.m0*T) and a plurality of data-to-clock edge
lengths corresponding to the specific data set type (P.sub.n0*T,
L.sub.m0*T).
[0036] It is noted that the write strategy parameters such as
Ttopr(n, m) and Tlast(n, m) can be tuned automatically since
specific devices (e.g. the oscilloscope mentioned above) are no
longer required according to the present invention. In addition,
without the agency of external devices, the write pulse controller
150 may tune the write strategy parameters according to the
data-to-clock edge deviations generated by the calculation module
140, so the write strategy parameters can be tuned automatically on
system or on chip according to the present invention. Through
tuning the write strategy parameters according to the data-to-clock
edge deviations, pit lengths or land lengths corresponding to data
newly written on the optical storage medium 102 utilizing the
latest updated write strategy parameters may approach target
multiples of T.
[0037] FIG. 3 illustrates a flowchart of a method 910 for tuning
write strategy parameters of an optical storage device according to
one embodiment of the present invention. The method 910 may be
implemented by system 100C shown in FIG. 1.
[0038] In Step 912, under the control of a firmware code executed
by a micro-processing unit (MPU) of the optical storage device 100,
the optical storage device 100 writes data on the optical storage
medium 102 utilizing initial values of the write strategy
parameters corresponding to a specific rotational speed of the
optical storage device 100.
[0039] In Step 914, the optical storage device 100 reads the data
newly written on the optical storage medium 102 to generate the
sliced signal 115.
[0040] In Step 916, the EFM length detector 130 of the system 100C
detects lengths P of pits and lengths L of lands by measuring the
sliced signal 115.
[0041] In Step 918, the calculation module 140 calculates
data-to-clock edge deviations corresponding to data set types
(L.sub.nT, P.sub.mT) and (P.sub.nT, L.sub.mT), where n=3, 4, . . .
, 11 and m=3, 4, . . . , 11 in this embodiment.
[0042] In Step 920, the MPU executing the firmware code determines
if tuning of the write strategy parameters is needed. If any of the
data-to-clock edge deviations is greater than a specific threshold,
the MPU executing the firmware code determines that tuning of the
write strategy parameters is needed, so Step 922 will be executed;
otherwise, enter Step 910E. The MPU may determine to enter Step 922
directly without examining Step 920 if initial values of the write
strategy parameters are certain to be imperfect. In addition,
although the write strategy parameters described in Steps 920 and
922 are plural write strategy parameters for simplicity as shown in
FIG. 3, this is not a limitation of the present invention. Both
Steps 920 and 922 can be described utilizing a singular form of
"write strategy parameter" if tuning of only a single write
strategy parameter is needed. Repeated explanation of the singular
or plural form for similar situations is therefore unnecessary in
the following.
[0043] If the MPU executing the firmware code determines to enter
Step 922, the system 100C tunes the write strategy parameters
utilizing the data-to-clock edge deviations as mentioned.
[0044] In Step 924, under the control of the MPU executing the
firmware code, the optical storage device 100 writes data on the
optical storage medium 102 utilizing the latest values of the write
strategy parameters.
[0045] Various data set types corresponding to combinations of a
target land length and a target pit length for this embodiment are
illustrated in the table shown in FIG. 4. The meaning of the
combinations has been explained as mentioned and is not repeated
here.
[0046] Please note that the number of data set types (L.sub.nT,
P.sub.mT) and (P.sub.nT, L.sub.mT) according to another embodiment
implemented for DVD-R disc or DVD+R disc mentioned above can be
derived as follows:
10*10*2=200;
since n=3, 4, . . . , 11, 14 and m=3, 4, . . . , 11, 14 for the
DVD-R disc or the DVD+R disc.
[0047] FIG. 5 is a block diagram of a system 200C for tuning write
strategy parameters of an optical storage device 200 according to a
second embodiment of the present invention. The second embodiment
is similar to the first embodiment, where the differences are
described as follows. The reference signal inputted into the EFM
length detector 130 is a reference clock CLK2 generated by an
oscillator 220. It is not necessary for the frequency of the
reference clock CLK2 to be equal to the frequency of the EFM data
clock CLK.
[0048] FIG. 6 is a block diagram of a system 300C for tuning write
strategy parameters of an optical storage device 300 according to a
third embodiment of the present invention. The third embodiment is
similar to the first embodiment, where the differences are
described as follows. The system 300C comprises a sampling circuit
coupled to the waveform equalizer 112 to receive the reproduced
signal such as the RF signal 113. The sampling circuit is utilized
for sampling the reproduced signal to generate a digital signal,
which is a digital RF signal 315 in this embodiment. As shown in
FIG. 6, the sampling circuit comprises an analog-to-digital
converter (ADC) 314 and a PLL 320. The ADC 314 performs
analog-to-digital conversion on the RF signal 113 according to a
reference clock CLK3 to generate the digital RF signal 315, and the
PLL 320 generates the reference clock CLK3 according to the digital
RF signal 315.
[0049] The system 300C further comprises an EFM length detector
330, a calculation module 340, and a write pulse controller 350,
where the calculation module 340 comprises a pattern dependency
classifier 342 and a data-to-clock edge deviation calculator 344.
The signal utilized for detecting the lengths is the digital RF
signal 315, not the sliced signal 115. The EFM length detector 330
detects intervals between time points by observing the value of the
digital RF signal 315, and generates the lengths of the intervals,
where each interval corresponds to a pit or a land. The boundary of
the intervals can be determined by a predetermined value, for
example, a middle value between a maximum value and a minimum value
carried by the digital RF signal 315, e.g. an average of the
maximum and minimum values. Such a middle value plays a role like
the slicing level mentioned in the previous embodiments.
[0050] FIG. 7 illustrates sample points (which are drawn with "s")
on a reproduced signal such as the RF signal 113, where a
difference d3 between a specific sample point's value and a
predetermined value (for example, the middle value mentioned above)
can be an indication for a data-to-clock edge deviation d4.
According to the waveform of the RF signal shown in FIG. 7, most of
the sample points crossing the predetermined value are perfectly
aligned to falling edges of the EFM data clock, so the values of
most data-to-clock edge deviations are zero. The specific sample
point's value mentioned above means a value sampled at the specific
sampling time and carried by the digital RF signal 315. Differences
between sample points' value and the predetermined value (for
example, the difference d3) can represent data-to-clock edge
deviations (for example, the data-to-clock edge deviation d4), and
the lengths and the data-to-clock edge deviations can be derived
accordingly. Therefore, the calculation module 340 may derive the
data-to-clock edge deviations by calculating differences between a
predetermined value (for example, the middle value) and the value
of the digital RF signal 315 around the time points when the value
of the digital RF signal 315 crosses the predetermined value.
[0051] Here, the pattern dependency classifier 342 performs the
same function as the pattern dependency classifier 142 while the
EFM length detector 330 may output lengths L and P carried by the
output signal 331 similar to the output signal 131. The
data-to-clock edge deviation calculator 344 of this embodiment
calculates the data-to-clock edge deviations utilizing the
approached direct line mentioned above. In addition, the write
pulse controller 350 performs the same function as the write pulse
controller 150 while the calculation module 340 may output the
data-to-clock edge deviations carried by the output signal 345
similar to the output signal 145.
[0052] FIG. 8 illustrates a variation of the embodiment shown in
FIG. 6, where an interpolator 416 coupled between the ADC 314 and
the PLL 320 is utilized. The PLL 320 generates a reference clock
CLK4 according to an interpolated signal 417 generated by the
interpolator 416, and the interpolator 416 performs an
interpolation operation according to the digital RF signal 315 and
the reference clock CLK4. In this variation, the input of the EFM
length detector 330 is replaced with the interpolated signal 417.
Operation principles of the interpolator 416 are well known in the
art and therefore not described in detail here.
[0053] In addition, although in the embodiments mentioned above,
each of the data set types corresponds to a combination of two
target lengths, such as (P, L) or (L, P), this is not a limitation
of the present invention. In other embodiments of the present
invention, each or one of the data set types may correspond to a
combination of at least a specific target pit length and specific
target land lengths, or a combination of at least a specific target
land length and specific target pit lengths, or a combination of
specific target land lengths and specific target pit lengths. For
example, each of the data set types may contain a combination of
three lengths, such as (P.sub.1, L, P.sub.2), (L.sub.1, P,
L.sub.2). As a result, the write strategy parameters can be tuned
further according to more adjacent pits or lands.
[0054] It should be noted that the present invention could be
implemented by means of hardware including a plurality of distinct
elements, or by means of a suitably programmed computer. In the
system claims detailing a plurality of means, several means can be
embodied by the same hardware or software device.
[0055] Those skilled in the art will readily observe that numerous
modifications and alterations of the device and method may be made
while retaining the teachings of the invention. Accordingly, the
above disclosure should be construed as limited only by the metes
and bounds of the appended claims.
* * * * *