Adjusting method for recording condition and optical disc device
View Patent ↗A method for evaluating reproduced signal wherein when Euclidean distance is calculated by judging the coincidence between a binary bit array and a predetermined evaluation bit array in the evaluation of the quality of reproduced signal, the assumption is made that a continuous 2T count included in a predetermined evaluation bit array is denoted by i and that each evaluation bit array is composed of a main bit array having a bit length of (5+2i); and judgment on whether binary bit arrays include the predetermined evaluation bit array, is concentrated on the coincidence judgment of the main bit arrays.
1. An adjusting method for recording condition for use with an optical disc device that records data into an optical disc medium by using codes whose shortest run length is 2T and reproduces the recorded data by using the adaptive equalizing procedure and the PRML procedure, comprising
a step of generating a first binary bit array by binarizing the reproduced signal waveform reproduced from the optical disc medium in accordance with the PRML procedure;
a step of generating a second binary bit array and a third binary bit array which are obtained by shifting the interested edge of the first binary bit array to the left and right, respectively;
a step of generating a first, a second and a third target signal waveforms corresponding to the first, second and third binary bit arrays, respectively;
a step of calculating a statistical average Δ of extended edge shifts D, wherein the reproduced signal waveform is denoted as W, the target signal waveform as T, the second target signal waveform as L, the third target signal waveform as R, Euclidean distances between W, T, R and L are denoted as ED(a,b) where a, b are ones of W, T, R and L, and evaluation value for the error caused when an edge of interest is shifted leftward is represented by xL and an evaluation value for the error caused when an edge of interest is shifted rightward is represented by xR, an amount of edge shift of an edge of interest is denoted as an extended edge shift D,
xL is represented by
xL
=
1
2
(
1
-
ED
(
L
,
W
)
-
ED
(
T
,
W
)
ED
(
T
,
L
)
)
xR is represented by
xR
=
1
2
(
1
-
ED
(
R
,
W
)
-
ED
(
T
,
W
)
ED
(
T
,
R
)
)
the extended edge shift D is represented by
D=(xR−xL)/2; and
a step of adjusting the recording condition by using Δ, where Δ is the statistical average of D.
2. An adjusting method for recording condition as claimed in claim 1 , wherein a Hamming distance between the first binary bit array and the second binary bit array is equal to the Hamming distance between the first binary bit array and the third binary bit array.
3. An optical disc device having the function of recording data into an optical disc medium by using codes whose shortest run length is 2T and reproducing the recorded data by using the adaptive equalizing procedure and the PRML procedure, comprising
a means for generating a first binary bit array by binarizing the reproduced signal waveform reproduced from the optical disc medium in accordance with the PRML procedure;
a means for generating a second binary bit array and a third binary bit array which are obtained by shifting the interested edge of the first binary bit array to the left and right, respectively;
a means for generating a first, a second and a third target signal waveforms corresponding to the first, second and third binary bit arrays, respectively;
a means for calculating a statistical average Δ of extended edge shifts D, where the reproduced signal waveform is denoted as W, the target signal waveform as T, the second target signal waveform as L, the third target signal waveform as R, an Euclidean distance between W, T, R and L is denoted as ED(a, b) where a, b are any ones of W, T, R and L, an evaluation value for the error caused when an edge of interest is shifted leftward is represented by xL and an evaluation value for the error caused when an edge of interest is shifted rightward is represented by xR, an amount of edge shift of an edge of interest is denoted as the extended edge shift D,
xL is represented by
xL
=
1
2
(
1
-
ED
(
L
,
W
)
-
ED
(
T
,
W
)
ED
(
T
,
L
)
)
xR is represented by
xR
=
1
2
(
1
-
ED
(
R
,
W
)
-
ED
(
T
,
W
)
ED
(
T
,
R
)
)
the extended edge shift D is represented by
D=(xR−xL)/2; and
a means for adjusting the recording condition by using Δ, where Δ is the statistical average of D.
4. A method for recording data comprising
a step of generating a first binary bit array by binarizing the reproduced signal waveform reproduced from the optical disc medium in accordance with the PRML procedure;
a step of generating a second binary bit array and a third binary bit array which are obtained by shifting the interested edge of the first binary bit array to the left and right, respectively;
a step of generating a first, a second and a third target signal waveforms corresponding to the first, second and third binary bit arrays, respectively;
a step of calculating a statistical average Δ of extended edge shifts D, wherein the reproduced signal waveform is denoted as W, the target signal waveform as T, the second target signal waveform as L, the third target signal waveform as R, Euclidean distances between W, T, R and L are denoted as ED(a, b) where a, b are ones of W, T, R and L, an evaluation value for the error caused when an edge of interest is shifted leftward is represented by xL and an evaluation value for the error caused when an edge of interests is shifted rightward is represented by xR, an amount of edge shift of an edge of interest is denoted as the extended edge shift D,
xL is represented by
xL
=
1
2
(
1
-
ED
(
L
,
W
)
-
ED
(
T
,
W
)
ED
(
T
,
L
)
)
xR is represented by
xR
=
1
2
(
1
-
ED
(
R
,
W
)
-
ED
(
T
,
W
)
ED
(
T
,
R
)
)
the extended edge shift D is represented by
D=(xR=xL)/2; and
a step of adjusting the recording condition by using Δ, where Δ is the statistical average of D;
wherein data is recorded using codes whose shortest run length is 2T, on the basis of the adjusted recording condition.