JP2007280492A - Recording or reproducing device, method, program, and recording signal regulating device, method, program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce error rates when recording information on an information recording medium, and also optimize the recording parameter conditions for stabilizing clock generation. <P>SOLUTION: The position displacements of recorded signals from their ideal edge positions are detected at beginning and end part of the recorded signals according to the recording pattern based on the digital signals and decoded results generated from the signals reproduced from an information recording medium, and the shape of the above recording signals is adjusted. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a recording / reproducing apparatus, a recording / reproducing method, a recording / reproducing program, a recording signal adjusting apparatus, a recording signal adjusting method, and a recording signal adjusting program for an information recording medium capable of recording information, and particularly, there are few errors in recorded information and RECORDING / REPRODUCING APPARATUS, RECORDING / REPRODUCING METHOD, RECORDING / REPRODUCING PROGRAM, RECORDING SIGNAL ADJUSTING APPARATUS, RECORDING SIGNAL ADJUSTING METHOD FOR OPTIMIZING A STABILIZED RECORDING / REPRODUCING SYSTEM And a recording signal adjustment program.

In general, an optical disk recording apparatus is used to prevent signal quality deterioration due to individual differences such as lot variations during optical disk manufacturing and optical head variations such as laser wavelength and light receiving element sensitivity in the optical disk recording apparatus. The recording condition is calibrated. The calibration is a control for optimizing the recording power or the pulse shape in order to ensure the signal quality of user data.
For example, Patent Literature 1, Patent Literature 2 and the like are known as conventional art examples of the calibration operation related to recording pulse counting. Japanese Patent Application Laid-Open No. 2004-228561 is a technique for optimizing the shape of a recording pulse using a maximum likelihood decoding method. Patent Document 2 is a technique for changing the recording pulse condition for the shortest recording mark and adjusting the recording pulse shape so that the jitter or the error rate is optimal.
The pulse shape optimization using the maximum likelihood decoding method of Patent Document 1 will be briefly described. A conventional optical disk drive will be described with reference to FIG.
Information read from the optical disk 26 is generated as an analog reproduction signal by the optical head unit 27. The analog reproduction signal is amplified by the preamplifier 28, AC-coupled, and then input to the AGC 29. In the AGC 29, the amplitude of the output of the waveform equalizer 30 at the subsequent stage is adjusted so as to have a constant amplitude. The analog reproduction signal whose amplitude is adjusted is shaped by the waveform equalizer 30 and input to the A / D converter 31. The A / D converter 31 samples the analog reproduction signal in synchronization with the reproduction clock output from the PLL circuit 32. The PLL circuit 32 extracts a reproduction clock from the digital reproduction signal sampled by the A / D converter 31.

  A digital reproduction signal generated by sampling of the A / D converter 31 is input to the shaping unit 33. The shaping unit 33 digitally reproduces the digital reproduction signal so that the frequency characteristic of the digital reproduction signal at the time of recording and reproduction becomes the characteristic assumed by the maximum likelihood decoding unit 34 (for example, PR (1, 2, 2, 1) equalization characteristic). Adjust the frequency. The maximum likelihood decoding unit 34 performs maximum likelihood decoding on the waveform-shaped digital reproduction signal output from the shaping unit 33 and generates a binarized signal. The reliability calculation unit 35 receives the waveform-shaped digital reproduction signal output from the shaping unit 33 and the binarized signal. The reliability calculation unit 35 determines the state transition from the binarized signal, and obtains | Pa−Pb | −Pstd indicating the reliability of the decoding result from the determination result and the branch metric. The pattern detection circuit 36 generates a pulse signal to be assigned for each pattern of the start / end edge of the recording mark based on the binarized signal and outputs the pulse signal to the edge shift detection circuit 37. The edge shift detection circuit 37 cumulatively adds the reliability | Pa−Pb | −Pstd for each pattern to obtain a deviation (hereinafter referred to as an edge shift) from the optimum value of the recording compensation parameter. The information recording medium controller 38 changes the recording parameter (the waveform of the recording signal) determined to be changed from the edge shift amount for each pattern. The pattern generation circuit 39 outputs a recording compensation learning pattern. The recording compensation circuit 40 generates a laser emission waveform pattern according to the recording compensation learning pattern based on the recording parameter changed by the information recording medium controller 38. The laser drive circuit 41 controls the laser emission operation of the optical head unit 27 in accordance with the generated laser emission waveform pattern.

As described above, the recording parameters are optimized so that the edge shift amount is minimized by repeating the recording and the reproduction with respect to the optical disk 26. Here, Pa and Pb in the reliability | Pa−Pb | −Pstd are the expected values of the two state transition sequences (path A and path B) determined by the equalization method PR and each transition between predetermined times. It is a value obtained by squaring the difference from the value of the digital reproduction signal corresponding to the time and accumulating each. Pstd is a value obtained by squaring the difference from each expected value of the path A and path B during the same time as Pa and Pb.
JP 2004-335079 A JP 2004-213865 A

In the maximum likelihood decoding method, a signal pattern is typically estimated from a reproduced signal waveform in advance, and the reproduced signal is decoded into a signal having the most probable signal pattern by comparing the reproduced signal waveform with the estimated signal waveform. It is a method to do. In the maximum likelihood decoding method, the smaller the difference between the reproduced signal waveform and the estimated signal waveform, the smaller the probability that an error will occur. For this reason, the error rate of the recording data is reduced by optimizing the recording parameters using the maximum likelihood decoding method as described above.
For example, there are an error rate and a jitter as index values for evaluating the quality of a reproduction signal in an optical disc (for example, DVD-RAM). The error rate represents the error rate of the decoded data of the reproduced signal. The smaller the numerical value, the smaller the error of the decoded data. Jitter represents the temporal error between the binarized signal edge position of the reproduced signal and the reproduced clock signal. The smaller the numerical value, the less the variation in the edge position of the binarized signal, and the more stable the clock generation in the PLL circuit. Become. Since the generated clock signal is used in each signal processing block (for example, an A / D converter) in the recording / reproducing apparatus, it is preferable that the jitter is small in order to perform signal processing with higher accuracy.
However, when the pulse shape optimization using the maximum likelihood decoding method of Patent Document 1 is performed, there is an effect of reducing the error rate, but the jitter may be deteriorated. Therefore, it is necessary to obtain a recording parameter that can improve jitter, that is, stabilize clock generation in the PLL circuit in a state where the error rate is not deteriorated as much as possible.

  The present invention reduces the error rate of recorded information on an information recording medium having an information recording surface on which information can be recorded, and optimizes the recording parameter condition that stabilizes clock generation in the PLL circuit, thereby making it more stable. An object of the present invention is to provide a recording / reproducing apparatus, a recording / reproducing method, a recording / reproducing program, a recording signal adjusting device, a recording signal adjusting method, and a recording signal adjusting program for realizing the recording / reproducing system.

  In order to achieve the above object, a recording / reproducing apparatus of the present invention includes a reproducing unit that generates a digital signal from an analog signal indicating information reproduced from an information recording medium, a decoding unit that decodes the digital signal, and the digital An adjustment unit for adjusting a shape of a recording signal for recording the information on the information recording medium based on the signal and a decoding result; and the information on the information recording medium based on the shape of the adjusted recording signal. A recording / reproducing apparatus including a recording unit for recording a pattern detection circuit for generating a pulse signal for assigning a start / end edge of a recording signal to each recording pattern, the digital signal, and a decoding result , And a positional deviation detection for detecting a positional deviation from an ideal edge position at the start / end of a recording signal corresponding to the recording pattern by the pulse signal. A length error Dl that is an error with respect to the length of the recording signal for each recording pattern or a phase error Dp that is an error with respect to the phase, or a length error based on the positional deviation between the circuit and the start and end portions of the recording signal A recording information error calculation unit that calculates both Dl and phase error Dp, and length error Dl or phase error Dp of at least one recording pattern in length error Dl or phase error Dp, or length error The shape of the recording signal for the recording pattern is adjusted with both Dl and the phase error Dp as error target values other than zero.

The recording / reproducing method of the present invention generates a digital signal from an analog signal indicating information reproduced from an information recording medium, decodes the digital signal, and records the information on the information recording medium based on the digital signal and a decoding result. Is a recording / reproducing method for recording the information on the information recording medium based on the adjusted shape of the recording signal, and adjusting the shape of the recording signal , Generating a pulse signal for allocating the start / end edge of the recording signal for each recording pattern, and the ideal edge at the start / end portion of the recording signal corresponding to the recording pattern by the digital signal, the decoding result, and the pulse signal The position deviation from the position is detected, and based on the position deviation of the start / end portion of the recording signal, an error in the length of the recording signal for each recording pattern is detected. A length error Dl or a phase error Dp which is an error relative to the phase, or both the length error Dl and the phase error Dp are calculated, and at least one recording pattern in the length error Dl or the phase error Dp is calculated. The shape of the recording signal with respect to the recording pattern is adjusted by setting the length error Dl or the phase error Dp or both the length error Dl and the phase error Dp as error target values other than zero.
The recording / reproducing program of the present invention includes a step of generating a digital signal from an analog signal indicating information reproduced from an information recording medium, a step of decoding the digital signal, and the information recording based on the digital signal and a decoding result. Adjusting a shape of a recording signal for recording the information on the medium, and causing a computer to execute a recording / reproducing process for recording the information on the information recording medium based on the adjusted shape of the recording signal The step of adjusting the shape of the recording signal includes generating a pulse signal for assigning the start and end edges of the recording signal for each recording pattern, the digital signal, the decoding result, and the Ideal edge position at the start and end of the recording signal according to the recording pattern by the pulse signal And a phase error that is an error with respect to the length of the recording signal for each recording pattern or a phase error that is an error with respect to the phase, based on the positional deviation at the start and end portions of the recording signal. Calculating Dp, or both length error Dl and phase error Dp, and calculating length error Dl or phase error Dp of at least one recording pattern in the length error Dl or phase error Dp, Alternatively, the shape of the recording signal with respect to the recording pattern is adjusted by setting the length error Dl and the phase error Dp to error target values other than zero.

The recording signal adjustment apparatus of the present invention adjusts the shape of a recording signal for recording information on an information recording medium based on information on the shape of the recording signal, a digital signal, and a decoding result of the digital signal. A pattern detecting means for generating a pulse signal for assigning start and end edges of a recording signal for each recording pattern; and a recording signal corresponding to the recording pattern by the digital signal, the decoding result, and the pulse signal. An error with respect to the length of the recording signal for each recording pattern based on the positional deviation detecting means for detecting the positional deviation from the ideal edge position at the start / end portion of the recording signal and the positional deviation of the start / end portion of the recording signal. A calculation for calculating a certain length error Dl or a phase error Dp which is an error with respect to the phase, or both the length error Dl and the phase error Dp. Information error calculation means, and the length error Dl or phase error Dp of at least one recording pattern in the length error Dl or the phase error Dp, or both the length error Dl and the phase error Dp are other than 0 As the error target value, the shape of the recording signal with respect to the recording pattern is adjusted.
The recording signal adjustment method of the present invention is a recording signal adjustment for adjusting the shape of a recording signal for recording information on an information recording medium based on information on the shape of the recording signal, a digital signal, and a decoding result of the digital signal. A method of generating a pulse signal for assigning a start / end edge of a recording signal for each recording pattern, and a start / end portion of the recording signal corresponding to the recording pattern by the digital signal, the decoding result, and the pulse signal A position error from an ideal edge position is detected, and a length error Dl that is an error with respect to the length of the recording signal for each recording pattern or an error with respect to the phase is detected based on the position deviation of the start / end portion of the recording signal The phase error Dp or the length error Dl and the phase error Dp are both calculated, and the length error Dl or the phase error Dp is calculated. The shape of the recording signal with respect to the recording pattern is adjusted with the length error Dl or the phase error Dp of at least one recording pattern or the length error Dl and the phase error Dp as both error target values other than zero. .

The recording signal adjustment program of the present invention performs an adjustment process for adjusting the shape of a recording signal for recording information on an information recording medium based on the information on the shape of the recording signal, the digital signal, and the decoding result of the digital signal. A recording signal adjustment program for causing a computer to execute, wherein the recording signal adjustment program generates a pulse signal for assigning start and end edges of a recording signal for each recording pattern, the digital signal, and the decoding result And a step of detecting a positional deviation from an ideal edge position at the start / end part of the recording signal according to the recording pattern by the pulse signal, and the recording based on the positional deviation of the start / end part of the recording signal. Length error Dl that is an error with respect to the length of the recording signal for each pattern or an error with respect to the phase Calculating a phase error Dp or a length error Dl and a phase error Dp together, and the length error Dl or the phase error Dp or the phase error Dp of at least one recording pattern in the phase error Dp. Or the length error Dl and the phase error Dp are both error target values other than 0, and the shape of the recording signal for the recording pattern is adjusted.
Note that the adjustment of the shape of the recording signal is performed by using the length error target value Dlt in which the length error Dl for each recording pattern is the target value of the length error or the phase error Dp for each recording pattern is the target value of the phase error. The shape of the recording signal with respect to the recording pattern is adjusted so that the phase error target value Dpt is set, or the length error Dl becomes the length error target value Dlt and the phase error Dp becomes the phase error target value Dpt. Including doing. Further, it includes that the length error target value Dlt of the at least one recording pattern is other than 0 and the phase error target value Dpt is 0.

The decoding result is the result of maximum likelihood decoding of the digital signal, and is calculated by reproducing the information recorded in advance on the information recording medium in the form of a recording signal adjusted to minimize jitter. The length error is Dlj and the phase error is Dpj, and the length error target value Dlt is set to 0 <Dlt <Dlj, or the phase error target value Dpt is set to 0 <Dpt <Dpj.
Note that the length error target value Dlt or the phase error target value Dpt includes different values depending on the recording medium information recorded on the information recording medium.

  By adjusting the shape of the recording signal by the recording / reproducing apparatus, the recording / reproducing method, the recording / reproducing program, the recording signal adjusting apparatus, the recording signal adjusting method, and the recording signal adjusting program of the present invention, the error rate of the recording information is reduced, In addition, recording can be performed under recording parameter conditions that stabilize clock generation in the PLL circuit, and a more stable recording / reproducing system can be provided.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The information recording medium in the embodiment of the present invention will be described as an arbitrary optical disc. The optical disc is, for example, a Blu-ray Disc Rewritable (hereinafter referred to as BD-RE).
First, a method for evaluating the reproduction signal quality when the maximum likelihood decoding method is used will be described. As an example, a recording code having a minimum polarity inversion interval of 2 is used as the recording code, and the signal waveform is such that the frequency characteristics of the signal during recording and reproduction are equal to PR (1, 2, 2, 1). A description will be given of a method for evaluating the quality of a reproduced signal when the signal is shaped.
The recording code is b _k , the recording code one hour before is b _k−1 , the recording code two hours before is b _k−2, and the recording code three times before is b _k−3 . An ideal output level Level _v of PR (1, 2, 2, 1) equalization is expressed by (Expression 1).

Here, k is an integer representing time, and v is an integer from 0 to 6.
If the state at time k is S (b _k−2 , b _k−1 , b _k ), the state transition table of Table 1 is obtained.

For simplicity, state S (0,0,0) _k at time k is S0 _k , state S (0,0,1) _k is S1 _k , and state S (0,1,1) _k is S2 _k. , state S (1, 1, 1) _k and S3 _k, state S (1,1,0) _k the S4 _k, when a state S (1, 0, 0) _k and S5 _k, the state shown in FIG. 2 A transition diagram is obtained. The state transition diagram shown in FIG. 2 represents a state transition rule determined from a recording code having a minimum polarity inversion interval of 2 and an equalization method PR (1, 2, 2, 1). When this state transition diagram is developed along the time axis, the trellis diagram of FIG. 3 is obtained. Attention is paid to the state S0 state of _k and time _k-4 S0 k-4 at time k. FIG. 3 shows two state transition sequences that can be taken between the state S0 _k and the state S0 _k-4 . Assuming that one possible state transition sequence is path A, path A transitions between states S2 _k-4 , S4 _k-3 , S5 _k-2 , S0 _k-1 , S0 _k . If another state transition sequence is a path B, the path B transits states S2 _k-4 , S6 _k-3 , S6 _k-2 , S5 _k-1 , S0 _k . If the maximum likelihood decoding result from time k-6 to time k is ( _Ck-6 , _Ck-5 , _Ck-4 , _Ck-3 , _Ck-2 , _Ck-1 , _Ck ) _{, (C k-6, C} k-5, C k-4, C k-3, C k-2, C k-1, C k) = (0,1,1, x, 0,0,0 ) (X is a value of 0 or 1), the state transition of path A or path B is estimated to be most likely. Since both the path A and the path B have the same probability of the state S2 _{k-4 at} the time k-4, the reproduction signals y _k-3 from the time k-3 to the time k of the path A and the path B respectively. By calculating the cumulative value of the square value of the difference between the value from y to y _k and the expected value of each of path A and path B, it can be seen that the state transition sequence of either path A or path B is likely. . Assuming that Pa is a cumulative value of the value obtained by squaring the difference between the value of the reproduction signal y _k-3 to y _k from time k-3 to time k and the expected value of path A, Pa is expressed by (Equation 2). It is represented by Assuming that an accumulated value of values obtained by squaring the difference between the values of the reproduction signals y _k-3 to y _k from the time k-3 to the time k and the expected value of the path B is Pb, Pb is expressed by (Expression 3) It is represented by

Here, the meaning of the difference Pa-Pb between Pa and Pb indicating the reliability of the decoding result will be described. It can be said that the maximum likelihood decoding unit selects the path A with confidence if Pa << Pb, and the path B with confidence if Pa >> Pb. If Pa = Pb, it does not matter whether path A or path B is selected, and it can be said that whether the decoding result is correct is 5 minutes 5 minutes. Thus, when Pa-Pb is obtained from the decoding result for a predetermined time or a predetermined number of times, a distribution of Pa-Pb is obtained. A schematic diagram of the distribution of Pa-Pb is shown in FIG.
FIG. 4A shows the Pa-Pb distribution when noise is superimposed on the reproduction signal. There are two peaks in the distribution, one having a maximum when Pa = 0, and the other having a maximum when Pb = 0. The value of Pa-Pb when Pa = 0 is expressed as -Pstd, and the value of Pa-Pb when Pb = 0 is expressed as Pstd. The absolute value of Pa-Pb is calculated to determine | Pa-Pb | -Pstd. FIG. 4B shows a distribution state of | Pa−Pb | −Pstd. A standard deviation σ and an average value Pave of the distribution shown in FIG. The distribution shown in FIG. 4B is a normal distribution. For example, based on σ and Pave, when the value of reliability | Pa−Pb | of the decoding result is −Pstd or less, Then, the error probability P (σ, Pave) is expressed as (Equation 4).

The error rate of the binarization result indicating the maximum likelihood decoding result can be predicted from the average value Pave calculated from the distribution of Pa-Pb and the standard deviation σ. That is, the average value Pave and the standard deviation σ can be used as an index of reproduction signal quality. In the above example, it is assumed that the distribution of | Pa−Pb | is a normal distribution. However, when the distribution is not a normal distribution, the value of | Pa−Pb | −Pstd is equal to or less than a predetermined reference value. It is also possible to count the number of times and use the counted number as an indicator of signal quality.
In the case of a state transition rule determined from the fact that the minimum polarity inversion interval is 2 and the equalization method PR (1, 2, 2, 1), a combination that can take two state transition sequences when the state transitions is There are 8 patterns in the range from time k-4 to time k, 8 patterns in the range from time k-5 to time k, and 8 patterns in the range from time k-6 to time k. When the detection range is further expanded, there is a reliable Pa-Pb pattern that can take two state transition sequences. What is important here is that if the reliability Pa-Pb is used as an index of the reproduction signal quality, even if all the patterns are erroneously detected (error rate), only the pattern having a large possibility of error (error rate) is detected. The detection result can be used as an index correlated with the error rate. Here, the pattern having a high possibility of error is a pattern in which the value of reliability Pa-Pb is small, and is 8 patterns in which Pa-Pb = ± 10. Table 8 summarizes these eight patterns and Pa-Pb.

  When the reliability Pa-Pb of the above eight decoding results is put together, (Formula 5) is obtained.

Here, A _k = (y _k −0) ² , B _k = (y _k −1) ² , C _k = (y _k −2) ² , D _k = (y _k −3) ² , E _k = ( y _k −4) ² , F _k = (y _k −5) ² , and G _k = (y _k −6) ² . Pa-Pb satisfying (Equation 5) is _obtained from the maximum likelihood decoding result _ck , and the standard deviation σ ₁₀ and the average value Pave ₁₀ are obtained from the distribution of Pa-Pb. Assuming that the distribution of Pa-Pb is a normal distribution, the probability P ₁₀ of causing an error is expressed by (Expression 6).

The eight patterns are patterns that cause a 1-bit shift error, and the other patterns are patterns that cause a shift error of 2 bits or more. When the error pattern after PRML processing is analyzed, most of them are 1-bit shift errors. Therefore, the error rate of the reproduction signal can be estimated by obtaining (Equation 6). Thus, the standard deviation σ ₁₀ and the average value Pave ₁₀ can be used as an index indicating the quality of the reproduction signal.
In the embodiment of the present invention, the detection of the above eight patterns is performed for each recording pattern described later (for each pattern that is a combination of the mark length and the space length before and after it), and the shape of the recording pulse, particularly the start / end portion of the edge Focusing on the above, a recording parameter for optimizing the edge shift position is determined. Of the reliability | Pa−Pb | of the maximum likelihood decoding results of all patterns, focusing on only the pattern having the minimum value of | Pa−Pb | means focusing only on the edge portion of the recording mark. means. As described above, a pattern with a small value of Pa-Pb is a pattern with a high error occurrence probability. That is, if the position of the edge of the recording mark is partially optimized so that the reliability of the maximum likelihood decoding result is high, it means that the entire optimization is achieved. The method will be described below.
5A to 5H show sample values of the above eight patterns (Pattern-1 to Pattern-8). The horizontal axis indicates time (one scale indicates the cycle (Tclk) of one channel clock), the vertical axis indicates the signal level (0 to 6), and the dotted line and the solid line indicate path A and path B, respectively. Each sample value corresponds to 0 to 6 of the input expected value Level in the maximum likelihood decoding described in Table 1. As shown in FIGS. 5C and 5D, the recorded portion (amorphous region) is reproduced as a waveform having a signal level lower than the threshold value of the comparator because reflected light is reduced. On the other hand, the unrecorded portion (non-amorphous region) is reproduced as a waveform above the threshold value of the comparator. Further, all of the eight patterns shown in FIG. 5 correspond to a reproduction waveform that is a boundary portion (starting edge and ending edge of a recording mark) between a recording portion (mark) and an unrecorded portion (space). Therefore, among the eight patterns in FIG. 5, Pattern-1, Pattern-2, Pattern-3, and Pattern-4 correspond to the start edge portion of the recording mark, and Pattern-5, Pattern-6, Pattern-7, and Pattern. -8 corresponds to the end edge portion of the recording mark.

Focusing on Pattern-1, a method for detecting the shift deviation of the start edge of the recording mark will be described. FIG. 6 shows the correlation between the reproduction waveform and the recording mark shift in Pattern-1. In FIG. 6, a solid line Δ mark is an input signal, and a path A indicated by a dotted line is a correct state transition path. The input signal is generated based on the recording mark B1. It is assumed that the recording mark A1 has an ideal starting edge. FIG. 6A shows a case where the starting edge position of the recording mark is shifted backward compared to the ideal starting edge position. The sample values (y _k−3 , y _k−2 , y _k−1 , y _k ) of the input signal are set to (4.2, 3.2, 1.2, 0.2), and (Equation 2) and ( The distance Pa between the path A and the input signal and the distance Pb between the path B and the input signal are obtained from (Expression 3) as shown in (Expression 7) and (Expression 8).

  The deviation amount and the deviation direction of the start edge can be obtained by calculating | Pa−Pb | −Pstd described above.

The absolute value of E1 obtained from (Equation 9) is the amount of deviation, and its sign is the direction of deviation. That is, in the case of FIG. 6A, since it can be detected that E1 = −2.4, it can be determined that the starting edge position is shifted behind the reference by 2.4.
Similarly, FIG. 6B shows a case where the starting edge position of the recording mark B1 is shifted forward compared to the ideal starting edge position. The sample values (y _k−3 , y _k−2 , y _k−1 , y _k ) of the input signal are set to (3.8, 2.8, 0.8, −0.2), and E2 (= | Pa When -Pb | -Pstd) is calculated, E2 = 2.4 can be calculated. That is, in the case of FIG. 6B, it can be determined that the starting edge position is shifted from the reference by 2.4.
FIG. 7 shows the correlation between the reproduction waveform in Pattern-1 and the shift of the recording mark. In FIG. 7, it is assumed that the path B is a correct state transition path. FIG. 7A shows a case where the starting edge position of the recording mark is shifted backward compared to the ideal starting edge position. The sample value (y _k-3 , y _k-2 , y _k-1 , y _k ) of the input signal is set to (5.2, 5.2, 3.2, 1.2), and E3 (= | Pa− If Pb | −Pstd) is calculated, E3 = 2.4 can be calculated. Therefore, in the case of FIG. 7A, it can be determined that the starting edge position is shifted from the reference by 2.4. FIG. 7B shows a case where the start edge position of the recording mark is shifted forward compared to the ideal start edge position. The sample value (y _k-3 , y _k-2 , y _k-1 , y _k ) of the input signal is set to (4.8, 4.8, 2.8, 0.8), and E4 (= | Pa− If Pb | −Pstd) is calculated, it can be calculated as E4 = −2.4. Therefore, in the case of FIG. 7B, it can be determined that the starting edge position is shifted from the reference by 2.4. In the case where the path A in FIG. 6 is correct and the path B in FIG. 7 is correct, the expression of the code indicating the shift direction of the start edge of the recording mark is opposite. This depends on the relationship between the expected value series of each of the correct answer path and the other candidate path and the input signal series. As shown in FIG. 6B and FIG. 7A, when the input signal sequence has a large error from the expected value sequence of a path that is not correct, the value calculated in (Equation 9) is positive. The value has a sign. In other words, the larger the difference between the input signal sequence and the expected value sequence of the path that is not the correct answer, the more unlikely an error will occur in maximum likelihood decoding. In this case, it is calculated as a positive sign value in (Equation 9). In consideration of this feature, the shift direction of the start edge position of the recording mark may be detected. In Pattern-1, when path A is correct, Pattern-1 is a pattern used when detecting the leading edge of a combination of a 2T space and a recording mark having a length of 4T or longer, and path B is correct. In this case, Pattern-1 is a pattern used when detecting the leading edge of a combination of a 3T space and a recording mark having a length of 3T mark or longer.

Furthermore, in this embodiment, a length error that is an error related to the length of the recording mark and a phase error that is an error related to the phase are obtained from the deviation amounts of the start edge and the end edge. Here, the length error and the phase error are not determined by optimizing the recording parameter to be determined with respect to the maximum likelihood decoding method, but the recording parameter that can be a good condition for the jitter value. This is for adjustment.
FIG. 8 shows the correlation between the reproduction waveform and the recording mark shift in Pattern-1 and Pattern-5. In FIG. 8, the solid line Δ mark is an input signal, and the correct state transition path at the start edge is defined as Pattern-1 path B, and the correct state transition path at the end edge is defined as Pattern-5 path B. The front space and the rear space are 3T spaces, and the recording mark is a 3T mark. The input signal is generated based on the recording mark B1. The recording mark A1 is an ideal recording mark. FIG. 8A shows a case where the length of the recording mark is shorter than the ideal recording mark and the center position (phase error) of the recording mark is correct. FIG. 8B shows a case where the length of the recording mark is correct with respect to the ideal recording mark, and the center position (phase error) of the recording mark is shifted backward.
In the case of FIG. 8A, it can be determined that the start edge position is shifted backward from the reference, and the end edge position is shifted forward from the reference. Since the length of the recording mark is shorter than the ideal length of the recording mark, a length error occurs. Further, when the deviation amounts of the start edge position and the end edge position are equal, the center position of the recording mark is the same position as the ideal recording mark, and the phase error is zero. If the reliability at the start edge position is | Pas-Pbs | and the reliability at the end edge position is | Pae-Pbe |, the deviation E5 of the start edge position is | Pas-Pbs | -Pstd, and the deviation of the end edge position E6 becomes | Pae-Pbe | -Pstd. Accordingly, the length error Dl and the phase error Dp of the recording mark are obtained as in (Expression 10) and (Expression 11).

  The absolute value of the length error Dl obtained from (Equation 10) represents the amount of deviation of the length of the recording mark, and the sign represents the direction of deviation. The absolute value of the phase error Dp obtained from (Expression 11) represents the phase shift amount of the recording mark, and the sign represents the shift direction. As described above, when the sequence of the input signal has a large error from the expected value sequence of the path that is not correct, the value obtained by (Equation 9) is a positive sign. Therefore, in FIG. 8A, since both the start edge and the end edge have a large error from the expected value sequence of the path that is not correct (in this case, path A), the shift direction of the edge position obtained by (Equation 9) is The sign to represent is positive. Accordingly, when the length error Dl obtained by (Equation 10) is a positive value, the recording mark recorded on the optical disc is shorter than the ideal recording mark, and when the negative value is negative, the recording mark is recorded on the optical disc. It can be determined that the recorded mark is longer than the ideal recorded mark. Further, when the phase error Dp obtained by (Equation 11) has a positive value, the recording mark recorded on the optical disk is shifted behind the ideal recording mark, and when the phase error Dp has a negative value, recording is performed on the optical disk. It can be determined that the recorded mark is shifted before the ideal recording mark. When the sign of the length error Dl calculated by (Equation 10) is reversed and the value of the length error is positive, the record mark recorded on the optical disc is longer than the ideal record mark. You may judge. Similarly, when the sign of the phase error Dp calculated by (Equation 11) is inverted and the value of the phase error becomes positive, the recording mark recorded on the optical disc is shifted before the ideal recording mark. It may be determined that

In FIG. 8A, the sample values (y _k−3 , y _k−2 , y _k−1 , y _k ) of the input signal at the starting edge are (5.2, 5.2, 3.2, 1). .2) The sample values (y _k−3 , y _k−2 , y _k−1 , y _k ) of the input signal at the termination edge are set to (1.2, 3.2, 5.2, 5.2). If E5 (= | Pas−Pbs | −Pstd) and E6 (= | Pae−Pbe | −Pstd) are calculated, E5 = 2.4 and E6 = 2.4. Therefore, the length error Dl = 4.8 and the phase error Dp = 0.0, and the recording mark length is shorter than the ideal recording mark, and the center position (phase error) of the recording mark is correct. It can be judged that there is.
Similarly, also in FIG. 8B, the sample values (y _k−3 , y _k−2 , y _k−1 , y _k ) of the input signal at the start edge portion are set to (5.2, 5.2, 3, .2, 1.2), and sample values (y _k−3 , y _k−2 , y _k−1 , y _k ) of the input signal at the terminal edge portion are (0.8, 2.8, 4.8, When E7 (= | Pas−Pbs | −Pstd) and E8 (= | Pae−Pbe | −Pstd) are calculated as 4.8), E7 = 2.4 and E8 = −2.4. Therefore, the length error Dl = 0.0 and the phase error Dp = 4.8, the recording mark length is correct with respect to the ideal recording mark, and the center position (phase error) of the recording mark is shifted backward. Can be judged.
By using the above-described method, the integrated value or average value for each start / end pattern of each recording mark is obtained, and the recording parameters are set so that the calculated deviation amounts of the length error and phase error approach zero. Thus, it is possible to perform optimum recording control for the maximum likelihood decoding method. When the recording parameters are set so that the deviation amounts of the length error and the phase error are close to 0, it is the same as the conventional technique, and the above problem cannot be solved. In the present embodiment, the length error or phase error of at least one or more start / end patterns in length error or phase error, or both the length error and phase error are set as error target values other than 0, the start / end pattern Set the recording parameters for. Thereby, it is possible to adjust the recording parameters so that both the reliability of the maximum likelihood decoding result and the signal quality indicators of jitter are compatible, and recording with higher accuracy can be performed. Henceforth, in a present Example, the error target value regarding length error is expressed as a length error target value, and the error target value regarding phase error is expressed as a phase error target value.

Next, a method for evaluating signal quality jitter will be described. FIG. 9 is an explanatory diagram for detecting jitter from the reproduced signal waveform of the recording mark. Here, as shown in FIG. 9A, attention is focused on a pattern of 2T space, 3T mark, 4T space, 2T mark, and 3T space as a part of the recording data. When this data series is reproduced, a reproduced signal waveform indicated by a solid line in FIG. 9B is obtained. A dotted line in the figure is a threshold value used for the binarization process, and is subjected to feedback processing so that the integration result of the binarized signal output becomes zero. Therefore, the reproduction signal waveform is binarized by the threshold value, and the binarized signal of FIG. 9C is obtained. Further, the binarized signal is input to the PLL circuit, the phase difference between the binarized signal and the regenerated clock signal is detected, and the regenerated clock signal shown in FIG. Is generated.
The time difference between the rising and falling edge positions of the binarized signal and the recovered clock signal becomes a phase error. That is, with respect to the recording mark in FIG. 9A, the phase error at the start edge position of the 3T mark is 2T in the front space, so Δt _2Ts3Tm . The phase error at the end edge position of the 3T mark is 4T in the back space. Delta] t _3Tm4Ts for some, the phase error in phase error Delta] t _4Ts2Tm for the preceding space is 4T, 2T mark termination edge position of the start edge position of the 2T mark is expressed as Delta] t _2Tm3Ts for the following space is 3T The Note that the mark length can be identified by the time interval between the rise and fall of the binarized signal. By detecting and integrating this phase error a plurality of times, the distribution of the phase error Δt as shown in FIG. 9E can be obtained. FIG. 9 (e) shows the distribution relating to the phase error Δt _2Ts3Tm (2T space-3T mark). It can obtain | require similarly about the start / end pattern of another recording mark. The average value of the distribution of the phase error Δt represents the edge position deviation. Therefore, if the recording parameters are set so that this edge position deviation approaches 0, optimum recording control can be performed for jitter. Further, the recording parameter may be set so that the accumulated value of the absolute value of the phase error Δt approaches 0 instead of the average value of the distribution of the phase error Δt.

Next, the length error target value Dlt and the phase error target value Dpt used for adjusting the recording parameters will be described.
FIG. 10 is a diagram for explaining the length error target value. Here, as in FIG. 8, the recording mark is a 3T mark, the space before and after is a 3T space, and the correct state transition path at the start edge and the end edge is path B. However, the solid line Δ mark that is an input signal is a signal example in which a recording mark formed with a recording parameter that is optimal for jitter is reproduced, and is a signal example that is relatively close to the path B that is the correct state transition path. is there. Since adjustment is performed so as to optimize the jitter, the start / end edge of the recording mark, that is, the intersection between the reproduction signal and the signal level 3 coincides with the cycle Tclk of the channel clock. However, it does not coincide with the path B, which is an accurate state transition path in the maximum likelihood decoding method, except at the intersection of the reproduced signal and the signal level 3. This is because the waveform equalization when detecting jitter and the waveform equalization when detecting the reliability of the maximum likelihood decoding result, that is, the boost amount for each frequency band is different. In this way, an error occurs between the reproduced signal and the path B that is the correct state transition path due to the difference in equalization characteristics between the signal processing system that performs jitter processing and the signal processing system that performs maximum likelihood decoding processing. . Therefore, the maximum likelihood decoding method according to the prior art can be performed only by adjusting the length error to a value other than 0 only for a recording pattern (for example, 3T mark) having the largest difference in equalization characteristics in the recording signal. The jitter is improved with respect to the optimization of the pulse shape using, that is, the effect of stabilizing the clock generation in the PLL circuit is obtained.

In FIG. 10, sample values (y _k−3 , y _k−2 , y _k−1 , y _k ) of the input signal at the starting edge are (4.8, 4.8, 3.0, 1.2). If the sample values (y _k-3 , y _k-2 , y _k-1 , y _k ) of the input signal at the end edge are (1.2, 3.0, 4.8, 4.8), The length error Dl = −1.6 and the phase error Dp = 0.0. In the recording parameter that is optimal for the maximum likelihood decoding method, the length error Dl = 0.0. In this case, the length error is set to a recording parameter that satisfies −1.6 <Dl <0.0. Thus, it is possible to perform recording control that is not biased to either the jitter or the reliability of the maximum likelihood decoding result. Therefore, the length error target value Dlt is between −1.6 and 0.0 (for example, an intermediate value). That is, when a length error detected as a result of reproducing a recording mark formed with a recording parameter that optimizes jitter is Dlj, the length error target value Dlt is 0 <Dlt <Dlj.
The phase error target value can also be obtained in the same manner as the length error target value. As a result of reproducing the recording mark formed with the recording parameter with the optimum jitter, if the detected phase error is Dpj, the phase error target value Dpt is 0 <Dpt <Dpj.
Note that the desired phase error target value Dpt in this embodiment is zero. However, when the phase error target value Dpt is 0, the length error target value Dlt of at least one recording pattern is a value other than 0, and more preferably when 0 <Dlt <Dlj described above. is there. As described above, regarding the length of the recording mark, it is necessary to finely adjust the length of each recording mark, that is, to finely adjust the length error in accordance with the equalization characteristics that are equalized when detecting jitter. There is. However, since it is desirable that the clock signals generated in the PLL circuit are always generated in the same phase, the center position of each recording mark and each space is an integral multiple of a half cycle of the channel clock, that is, Tclk / 2 × n (n Is a positive number), and a recording state in which the phase error is 0 is desirable. Accordingly, in a preferred embodiment of the present invention, the phase error target value Dpt is 0, and the length error target value Dlt of at least one or more recording patterns is a value other than 0, more preferably 0 <Dlt <Dlj described above. It is.

Next, recording parameter adjustment will be described.
The recording parameter in this embodiment is a parameter for forming a recording pulse. FIG. 11 shows a recording pulse for each recording mark in the present embodiment.
The recording power of the recording pulse depends on the peak power Pw, the bias power Pb, the cooling power Pc necessary for forming the recording mark, and the erase power Pe necessary for erasing the existing recording mark to form a space portion. Composed. The peak power Pw, bias power Pb, cooling power Pc, and erase power Pe are set with the extinction level detected when the laser light is extinguished as a reference level. In this embodiment, the peak power Pw, the bias power Pb, the cooling power Pc, and the erase power Pe are set to be the same for each recording mark. However, in order to form a more appropriate recording mark, the recording mark You may change the power according to the length and the space length before and after.
Regarding the pulse width, the pulse width Ttop of the leading pulse (hereinafter referred to as top pulse) is set by recording signals of 2T, 3T, 4T, and 5T marks or more. In FIG. 11, Ttop2T represents a 2T mark, Ttop3T represents a 3T mark, Ttop4T represents a 4T mark, and Ttop5T represents a pulse width of a top pulse with respect to a recording mark of 5T mark or more. In addition, the width Tmp of the pulse after the top pulse (hereinafter referred to as multi-pulse) existing in the recording pulse of 3T or more is set to be the same. The length of the recording mark is determined according to the number of multipulses. For example, a 6T mark results in a recording signal having one more multipulse than a 5T mark.

However, in this embodiment, the pulse width and position may be variable by setting the pulse width of the final pulse (hereinafter referred to as the last pulse) to Tlp instead of Tmp. In this case, the pulse width is expressed as Tlp3T for the 3T mark, Tlp4T for the 4T mark, and Tlp5T for the 5T mark or more. The pulse position is expressed as dTlp3T for the 3T mark, dTlp4T for the 4T mark, and dTlp5T for the 5T mark or more.
Further, the rising position dTtop of the top pulse and the position dTe where the cooling power after the last pulse ends (position where the cooling power returns to the erase power) can be varied. In FIG. 11, dTop2T represents a 2T mark, dTtop3T represents a 3T mark, dTtop4T represents a 4T mark, and dTtop5T represents a change in the rising position of the top pulse with respect to a recording mark of 5T mark or more. DTe2T represents a 2T mark, dTe3T represents a 3T mark, dTe4T represents a 4T mark, and dTe5T represents a change in the end position of the cooling power with respect to a recording mark of 5T mark or more.
Information on the recording power, pulse width, and pulse position of the recording pulse is described in the optical disk. Therefore, the recording pulse written on the optical disk is used as the recording parameter of the initial condition. However, the pulse position (for example, dTlp) in this embodiment is set to 0 if it is not described on the optical disk.

By changing Ttop2T and / or dTtop2T for 2T mark, Ttop3T and / or dTtop3T for 3T mark, Ttop4T and / or dTtop4T for 4T mark, and Ttop5T and / or dTtop5T for 5T mark at the beginning of the recording mark Can be adjusted. At the end of the recording mark, dTe2T and / or Ttop2T for 2T mark, dTe3T (and / or Tlp3T) for 3T mark, dTe4T (and / or Tlp4T) for 4T mark, dTe5T (and / or Tlp5T) for 5T mark By doing so, the end edge position of the recording mark can be adjusted.
Therefore, since the length and phase of the recording mark change by simultaneously changing the start edge position and the end edge position, the length error and phase error detected in this embodiment can be adjusted.
For example, when the length of the recording mark is increased, the value of dTtop and / or Ttop in each recording mark is increased and the value of dTe is decreased. When the length of the recording mark is shortened, the value of dTtop and / or Ttop in each recording mark is decreased and the value of dTe is increased.

Further, for example, when the phase of the recording mark is advanced from that of other marks (closer to the previous recording mark), the values of dTtop and dTe are increased. In the case where the phase of the recording mark is delayed with respect to the other marks (closer to the recording mark behind), the values of dTtop and dTe are reduced.
When changing the length and phase of the recording mark, it is desirable to change the pulse width Tlp and the position of the last pulse when the recording sensitivity of the trailing edge is low even if dTe is changed.
Next, recording patterns detected in the present embodiment will be described. FIG. 12 shows which of the eight patterns (Pattern-1 to Pattern-8) is used to detect the recording pattern in this embodiment. At the start edge of FIG. 12, for example, when the previous space is 2Ts and the recording mark is 3Tm and the recording mark is 3Tm, the recording pattern is a P3A pattern, and the detection of the shift amount of the signal corresponding to the start / end pattern of the recording mark is detected. Means to do. Here, P3A is Pattern-3 and means a pattern in which the path A is a correct state transition path. Similarly, with respect to the end edge in FIG. 12, for example, when the back space is 3Ts with a 3T space and the recording mark is 3Tm with a 3T mark, the recording pattern is a P1B or P4A pattern. Here, P1B is a pattern that is Pattern-1 and path B is a correct state transition path, and P4A is a pattern that is Pattern-4 and path A is a correct state transition path.

In FIG. 12, the recording mark is a 2T mark (2Tm), and the space before and after it is 2T space (2Ts), that is, 2Ts2Tm (2T space-2T mark) or 2Tm2Ts (2T mark-2T space) is the above 8 patterns (Pattern). -1 to Pattern-8) cannot be detected. However, since the pattern including 2Ts2Tm and 2Tm2Ts is a pattern having a relatively high value of reliability Pa-Pb, it is not included in the eight patterns. In other words, even if the edge portions of 2Ts2Tm and 2Tm2Ts are not strictly optimized, it can be said that there is a low possibility of an error in the maximum likelihood decoding.
Accordingly, in consideration of each recording mark and the space before and after, the recording pattern detected as the length error and phase error of the recording mark is shown in FIG.
FIG. 13 shows a recording pattern for the front space-recording mark-back space. For example, 2Ts3Tm4Ts indicates that the front space represents a 2T space, the recording mark represents a 3T mark, and the rear space represents a 4T space. Further, when the recording mark is a 2T mark and the space before and after is a 2T space, detection is impossible. Length errors and phase errors for other patterns can be detected. In the case of using the maximum likelihood decoding shown in the present embodiment, a recording pattern including a 2T mark and a 2T space cannot be detected, but even when a recording pattern including a 2T mark and a 2T space can be detected by another decoding method. The present invention is applicable.

In addition, if the optical disc can detect the length error and phase error of each recording mark without being affected by the preceding and following spaces, it is not always necessary to detect all the 57 recording patterns shown in FIG. It is only necessary to detect four types of 3T mark, 4T mark, and 5T mark or more. Further, all the marks from the shortest recording mark to the longest recording mark may be detected. For example, in the case of a recording signal in which the shortest mark is 2T and the longest mark is 8T, there are seven ways. Further, if the optical disc can be detected as 4T or more, such as 5T mark or more, the number of recording patterns to be detected is reduced to 41. In these cases, the length error and the phase error may be detected in accordance with the difference in the length of the recording mark, the signal processing system for detecting and processing the space portion in the recording / reproducing apparatus, and the memory for storing the error target value Part capacity can be reduced, that is, the circuit scale can be reduced. In this way, a recording pattern to be detected may be determined as necessary.
The method for controlling the optimum recording parameter in the present embodiment is that the recording parameter in FIG. 13 is adjusted so that the shift amount of the signal corresponding to each recording pattern with respect to the recording mark length error and phase error approaches each target value. Is to change. The length error Dl and the phase error Dp of the recording mark can be obtained by (Equation 10) and (Equation 11) for each recording pattern, and at least the length error Dl or the phase error among all the recording patterns. Adjusting the length error Dl or the phase error Dp for the recording pattern having the largest Dp error amount can adjust the recording parameter most efficiently.

Next, an example of adjusting a recording pulse using a length error and a phase error will be described. However, in the description here, the recording mark is a 3T mark, the front space and the rear space are arbitrary lengths, and the description of all patterns shown in FIG. 13 is omitted. The pulse setting for forming the last pulse is variable.
FIG. 14 is a diagram illustrating an example in which the length of the 3T mark changes due to a change in the recording pulse.
14A to 14E, the pulse width Ttop and phase dTtop of the top pulse in the recording pulse of the 3T mark, and the position dTe where the cooling power after the last pulse ends (position where the cooling power returns to the erase power) are shown. It is changed at a constant time interval Δt. As a result, recording marks are formed for the respective recording pulses shown in FIGS. In this case, the length of the recording mark in FIG. 14 (a) is the shortest, and the length of the recording mark in FIG. 14 (e) is the longest.
Further, when the start edge portion and the end edge portion of the recording mark are changed at the same time, it is ideal that the change of the recording mark at both edge portions is the same. However, for example, in the case where the amount of heat of laser light varies depending on the type of optical disk such as the medium and structure constituting the optical disk, the change in the recording mark at both edge portions may not be the same. In this case, the phase of the recording mark changes. Therefore, for the purpose of adjusting the phase of the recording mark, it is more desirable to adjust the phase after adjusting the length of the recording mark.

As shown in FIGS. 14A to 14E, recording data including a 3T mark is recorded under a recording condition in which the length of the 3T mark changes, and a recording area under each recording condition is reproduced and signal-processed. A 3T mark length error is detected. FIG. 15 is a diagram for explaining a change example of the length error of the 3T mark detected from the recording mark whose length is changed under the recording conditions of FIGS. 14 (a) to 14 (e). Symbols (a) to (e) in FIG. 15 correspond to the recording conditions (a) to (e) in FIG. 14 and are results of length errors obtained by reproducing and signal processing each recording area. Accordingly, the length error of the 3T mark in the symbol (a) in FIG. 15 is detected as the shortest, and the length error of the 3T mark in the symbol (e) is detected as the longest.
Here, since the optimum recording condition for the maximum likelihood decoding method is when the length error is 0, the selected recording condition is the symbol (c) closest to 0. However, if the length error target value in this embodiment is the length error represented by the dotted line in FIG. 15, the selected recording condition is the symbol (d) closest to the length error target value. In this way, it is possible to adjust the recording pulse such that the recording condition under which the length of the recording mark changes is changed and the detected length error approaches the predetermined length error target value.
FIG. 16 is a diagram illustrating an example in which the phase of the 3T mark changes due to a change in recording pulse.

16A to 16E, all edge positions in the recording pulse of the 3T mark, that is, the phase dTtop of the top pulse, the phase dTlp of the last pulse, and the position dTe where the cooling power after the last pulse ends (from cooling power to erase). The position where the power returns) is changed at a constant time interval Δt. Thereby, recording marks for the respective recording pulses in FIGS. 16A to 16E are formed (the same figure). In this case, the phase of the recording mark in FIG. 16A is the rearmost (farthest from the previous recording mark), and the phase of the recording mark in FIG. close).
In FIG. 16, since the phase of the entire 3T mark is changed, the length of the recording mark itself does not change. The same applies to the 2T mark, and the phase can be changed without changing the length. However, as shown in FIG. 11, the reference position of the recording pulse is the rising edge position of the multipulse. Therefore, for the 4T mark or more, the rising edge position of the reference multi-pulse cannot be changed. That is, the multipulse width Tmp can be varied, but the pulse position cannot be changed. Therefore, the time interval between the top pulse and the multi-pulse or between the multi-pulse and the last pulse is not constant when the phase changes beyond the 4T mark. Therefore, even if the pulse width and position of the recording pulse are changed as necessary. Good. For example, the top pulse width Ttop is increased and the last position change is set to Δt / 2 instead of Δt. However, it is more desirable to detect and check the length error to see if the length of the recording mark has changed due to the change in the recording pulse.

As shown in FIGS. 16A to 16E, recording data including a 3T mark is recorded under recording conditions in which the phase of the 3T mark changes, and a recording area under each recording condition is reproduced and signal-processed. A mark phase error is detected. FIG. 17 is a diagram for explaining a change example of the phase error of the 3T mark detected from the recording mark whose phase is changed under the recording conditions of FIGS. Symbols (a) to (e) in FIG. 17 correspond to the recording conditions (a) to (e) in FIG. 16 and are the results of phase errors obtained by reproducing and signal processing each recording area. Accordingly, it is detected that the phase error of the 3T mark in the symbol (a) in FIG. 17 is the rearmost, and the phase error of the 3T mark in the symbol (e) is detected as the foremost.
Here, when the length error target value of at least one recording pattern is a value other than 0, the desired phase error target value in this embodiment is 0. Therefore, the recording condition selected in FIG. The symbol (c) closest to the error target value is obtained. In this way, it is possible to adjust the recording pulse so that the recording condition in which the phase of the recording mark changes is changed and the detected phase error approaches a predetermined phase error target value. Note that the difference from the prior art is that the length error and the phase error are adjusted to be 0 simultaneously in the prior art, but in this embodiment, the length error is not 0. The phase error can be adjusted to be zero. Conversely, the length error can be adjusted to zero even when the phase error is other than zero. In addition to adjusting both the length error and the phase error, adjustment may be made only for one of the length error and the phase error.

Next, the recording / reproducing apparatus in the embodiment of the present invention will be described.
FIG. 1 shows a recording / reproducing apparatus 100 which is a first recording / reproducing apparatus in an embodiment of the present invention. The recording / reproducing apparatus 100 includes a reproducing unit 101, a recording control device 102, and a recording unit 103, and executes the above-described recording parameter optimization method.
The reproducing unit 101 includes an optical head unit 2, a preamplifier 3, an AGC 4, a waveform equalizer 5, an A / D converter 6, and a PLL circuit 7. The reproduction unit 101 generates a digital signal from an analog signal indicating information reproduced from the information recording medium 1. Here, the information recording medium 1 is an optical disc, for example.
The recording control apparatus 102 includes a shaping unit 8, a maximum likelihood decoding unit 9, a reliability calculation unit 10, and an adjustment unit 104. The adjustment unit 104 includes a pattern detection circuit 11, an edge shift detection circuit 12, a recording information error calculation unit 13, and an information recording medium controller 14. The information recording medium controller 14 includes an error target value storage unit 15 that stores a length error target value and a phase error target value. Note that information is recorded on the information recording medium with recording parameters that are optimal with respect to other index values (for example, jitter), and the information recording medium controller 14 reproduces the information to obtain the length error and phase. If the error is detected and the length error target value and the phase error target value are determined according to the length error and the phase error, the error target value storage unit 15 is not necessary. The recording control device 102 is manufactured as a semiconductor chip, for example.

The shaping unit 8 is a digital filter, for example, and receives the digital signal generated by the reproduction unit 101 and shapes the waveform of the digital signal so that the digital signal has a predetermined equalization characteristic. If the digital signal is a signal with little reproduction distortion, the shaping unit 8 is not necessary. The maximum likelihood decoding unit 9 is, for example, a Viterbi decoding circuit, which performs maximum likelihood decoding on the digital signal whose waveform is output from the shaping unit 8 and generates a binary signal indicating the result of maximum likelihood decoding. The means for decoding the digital signal is not limited to the maximum likelihood decoding unit 9, and other decoding means may be used.
The reliability calculation unit 10 is, for example, a differential metric detection circuit, and performs maximum likelihood decoding based on the digital signal obtained by shaping the waveform output from the shaping unit 8 and the binary signal output from the maximum likelihood decoding unit 9. Calculate the reliability of the results. In the present embodiment, since the reliability calculation unit 10 performs calculation on the result of maximum likelihood decoding, the reliability calculation unit 10 has a partial function of the maximum likelihood decoding unit 9, and the result of the maximum likelihood decoding Reliability calculation results are also handled as decryption results. In addition, the reliability calculation unit 10 calculates the reliability of the maximum likelihood decoding result based on the digital signal and the binarized signal corresponding to the start / end edge positions of the recording marks formed on the information recording medium 1.
The recording information error calculation unit 13 includes, for example, an adder and a subtracter, and calculates the length error and phase error of the recording signal based on the reliability output from the reliability calculation unit 10.

The adjustment unit 104 adjusts the shape of the predetermined portion with respect to the recording signal for recording information on the information recording medium 1 based on the length error and phase error of the recording signal calculated by the recording information error calculation unit 13. (For example, the position of the edge of the recording signal is adjusted). The adjustment unit 104 adjusts the shape of the recording signal so that the length error and phase error of the recording signal approach the error error target values of the length error and phase error stored in the error target value storage unit 15. The information recording medium controller 14 controls each unit in the recording / reproducing apparatus such as the reproducing unit 101, the recording control device 102, the recording unit 103, and a servo control unit (not shown) in order to adjust the shape of the recording signal. The information recording medium controller 14 also performs a recording pulse condition determination process when adjusting the shape of the recording signal. The information recording medium controller is, for example, an optical disk controller.
The recording unit 103 includes a pattern generation circuit 16, a recording compensation circuit 17, a laser driving circuit 18, and the optical head unit 2. The recording unit 103 records information on the information recording medium 1 based on the adjustment result of the shape of the recording signal. In the present embodiment, the optical head unit 2 is shared by the reproducing unit 101 and the recording unit 103, and has both functions of a recording head and a reproducing head. Note that the recording head and the reproducing head may be provided separately. The operation of the recording / reproducing apparatus 100 will be described in more detail below.

The optical head unit 2 generates an analog reproduction signal indicating information read from the information recording medium 1. The analog reproduction signal is amplified by the preamplifier 3 and AC coupled, and then input to the AGC 4. In the AGC 4, the gain is adjusted so that the output of the subsequent waveform equalizer 5 has a constant amplitude. The analog reproduction signal output from the AGC 4 is shaped by the waveform equalizer 5. The analog reproduction signal whose waveform has been shaped is output to the A / D converter 6. The A / D converter 6 samples the analog reproduction signal in synchronization with the reproduction clock output from the PLL circuit 7. The PLL circuit 7 extracts a reproduction clock from the digital reproduction signal sampled by the A / D converter 6.
A digital reproduction signal generated by sampling of the A / D converter 6 is input to the shaping unit 8. The shaping unit 8 causes the frequency characteristic of the digital reproduction signal at the time of recording and reproduction to be the characteristic assumed by the maximum likelihood decoding unit 9 (PR (1, 2, 2, 1) equalization characteristic in the present embodiment). Adjust the frequency of the digital playback signal. That is, the waveform of the digital reproduction signal is shaped.
The maximum likelihood decoding unit 9 performs maximum likelihood decoding on the waveform-shaped digital reproduction signal output from the shaping unit 8 and generates a binarized signal. The reliability calculation unit 10 receives the waveform-shaped digital reproduction signal output from the shaping unit 8 and the binarized signal. The reliability calculation unit 10 determines the state transition from the binarized signal, and indicates the reliability of the decoding result from the determination result and the branch metric | Pa-Pb | -Pstd (see (Equation 9), hereinafter referred to as Pabs) Ask for. Based on the binarized signal, the pattern detection circuit 11 generates a pulse signal for assigning the eight patterns (Pattern-1 to Pattern-8) for each pattern of the start / end edge of the recording mark shown in FIG. To the edge shift detection circuit 12. The edge shift detection circuit 12 cumulatively adds the reliability Pabs for each pattern to obtain a deviation (edge shift) from the optimum value of the recording compensation parameter. The recording information error calculation unit 13 adds and uses the edge shift of the start / end output from the edge shift detection circuit 12 so as to correspond to each recording pattern for the preceding space-recording mark-backing space shown in FIG. Subtraction is performed to calculate the length error and the phase error (see (Expression 10) and (Expression 11)). The information recording medium controller 14 compares the length error and the phase error calculated by the recording information error calculation unit 13 with each error target value of the length error and the phase error stored in the error target value storage unit 15. Based on the result, for example, a recording parameter (recording signal waveform) determined to be changed is changed such that there is a recording parameter whose difference from the error target value is larger than a predetermined value. The pattern generation circuit 16 outputs a recording compensation learning pattern. Here, the error target value stored in the error target value storage unit 15 is preferably set for each optical disk of each disk manufacturer, and for example, a value is stored in the manufacturing process of the recording / reproducing apparatus. Further, since the error target value corresponding to the newly developed optical disk is further stored in the error target value 15, it becomes possible to cope with the new optical disk. Therefore, the error target value storage unit 15 is a rewritable memory. It is desirable to be. The error target value for the new optical disc can be determined by reproducing the recording mark formed by the recording / reproducing apparatus 100 with the recording parameter that is optimum for the jitter. For example, assume that a length error detected by reproducing a recording mark with a good jitter value is −1.6 and a phase error is +0.2. Since the length error and the phase error are 0.0 in the recording parameter that is optimal for the maximum likelihood decoding method, the length error target value is between −1.6 and 0.0 (for example, an intermediate value), and the phase The error target value can be determined as a value between 0.0 and +0.2 (for example, an intermediate value). Therefore, as a result of reproducing the recording mark formed with the recording parameter with the optimum jitter, if the detected length error is Dlj and the phase error is Dpj, the length error target value Dlt is 0 <Dlt <Dlj, or The phase error target value Dpt is 0 <Dpt <Dpj.

The recording compensation circuit 17 generates a laser emission waveform pattern according to the recording compensation learning pattern based on the recording parameters from the information recording medium controller 14. The laser drive circuit 18 controls the laser emission operation of the optical head unit 2 in accordance with the generated laser emission waveform pattern.
Here, the test recording pattern used when adjusting the recording parameters will be described. In the PLL circuit 7 in FIG. 1, the slicer threshold value is automatically detected using the DC component (low frequency component included in the reproduction signal), and the reproduction signal and the clock signal are synchronized. Therefore, it is desired that the test recording pattern has a small DC component so that the feedback control does not affect the clock generation in the PLL circuit 7. In view of the time and accuracy required for optimization, a highly accurate detection result is desired with as few recording areas as possible. Therefore, the mark and space combinations necessary for parameter optimization occur in the test recording pattern at the same frequency, and the DC component (DSV) included in the code is 0, and the unit of the combination necessary for optimization A test recording pattern that increases the frequency of occurrence per length is required. An example of such a test recording pattern is shown in FIG.
In FIG. 18, 2M means a 2T mark, and 2S means a 2T space. In FIG. 13, there are 57 patterns of combinations of the 2T-5T front space, the 2T-5T recording mark, and the 2T-5T rear space. When the recording mark and space of 5T or more are 5T, and the first front space of the test recording pattern is the last rear space of the test recording pattern, the test recording pattern is composed of 414 bits. However, in this case, the number of symbols '0' and symbols '1' including a 414-bit recording pattern is not the same, symbol '0' is 210 bits, symbol '1' is 204 bits, and symbol '0' is 6 There are more bits. The reason that the number of symbols is not the same is because the recording pattern that is a combination of 2T mark and 2T space is excluded. Therefore, in order to set the DSV of the test recording pattern to 0, it is necessary to add further recording marks and spaces as dummy patterns so that the symbol “1” is 6 bits larger than the symbol “0”.

The addition of this dummy pattern will be described with reference to FIG. First, attention is focused on the leading pattern “2M6S3M5S” in the test recording pattern of FIG. This pattern is a dummy pattern in this embodiment. This is a pattern example in which all patterns following this dummy pattern are composed of 57 patterns. When the dummy pattern is added before 57 patterns, the last pattern of the dummy pattern is “5S” so that the pattern “2M5S” immediately after the dummy pattern becomes the original pattern “5S2M5S” (one of 57 patterns). Must be set to Here, “5S” is selected because the end of the test recording pattern in FIG. 18 is “5S”.
In order to set the last of the dummy pattern as a space, it is necessary to set the recording mark immediately before that from 2T to the longest (for example, 8T) recording mark. Here, a 3T mark is used as an example. Therefore, the dummy pattern at this point is “3M5S”, and the symbol “1” has only 2 bits more than the symbol “0”, and the difference of 6 bits cannot be eliminated. Even if the shortest 2T mark is set instead of the 3T mark, the same is true. Therefore, it is necessary to further increase the recording mark and space before the dummy data “3M5S”. However, in this case, the symbol “1” only needs to select a pattern having 4 bits more than the symbol “0”. In the example of FIG. 18, “2M6S” is set. Therefore, the dummy pattern is a pattern having at least two recording marks and spaces (here, “2M6S3M5S”), and the DSV can be set to zero. Further, as the appearance frequency, two 57 places occur once, but the test recording pattern is almost as close as the same appearance frequency.

The place where the dummy pattern is added is not limited to the top part of the test recording pattern, but may be added to some of the 57 test recording patterns. Further, since the test recording pattern includes a dummy pattern, it is not always necessary to repeat the 57 test recording patterns, and other test recording patterns (for example, a single signal or a specific pattern) are necessary. May be included. In the present embodiment, it is assumed that recording marks and spaces of 5T or more can be recorded with the same recording parameters. Similarly, when a recording pattern including a 2T mark and a 2T space can be detected by another decoding method, the DSV is 0 and a test recording pattern including the 2T mark and the 2T space may be used.
As an example of the operation of the recording / reproducing apparatus 100 described above, the information recording medium controller 14 in the recording control apparatus 102 adjusts the laser emission waveform pattern of the recording compensation circuit 17 to the optimum recording pulse condition (hereinafter, recording pulse adjustment). I will explain to you. Here, the information recording medium 1 is an optical disc, and the parameter to be adjusted is a recording pulse of a 3T mark.
In general recording pulse adjustment, for example, the recording pulse conditions such as the top pulse width Ttop and the phase dTtop are changed at regular intervals, recording data is recorded on the track of the optical disc, and each recorded data is reproduced. Then, by performing quality evaluation (for example, jitter value) of the reproduction signal, the optimum recording pulse condition for the optical disc is determined.

In the present invention, the means for controlling the pulse width and phase of the recording pulse is the recording compensation circuit 17 that generates the laser emission waveform pattern, and the information recording medium controller 14 controls the recording compensation circuit 17. The information recording medium controller 14 acquires the recording pulse information described on the optical disc and determines it as an initial value of the recording pulse condition for laser emission, and the recording compensation circuit 17 generates a laser emission waveform pattern corresponding to the initial value. Instruct to generate. Further, the information recording medium controller 14 instructs the laser driving circuit 18 and the optical head unit 2 to record the recording data on the track of the optical disc according to the generated laser emission waveform pattern.
In the recording pulse adjustment for adjusting the length error, the recording / reproducing apparatus 100 has a recording pulse condition in which the length of the recording mark changes (for example, the top pulse width Ttop and phase dTtop of the 3T mark, and the cooling power after the last pulse). Recording data is recorded for each predetermined area (for example, address unit) on the track while changing the end position dTe). In the recording pulse adjustment for adjusting the phase error, the recording / reproducing apparatus 100 uses the recording pulse conditions in which the phase of the recording mark changes (for example, the phase dTtop of the top pulse of the 3T mark, the phase dTlp of the last pulse, and the cooling power after the last pulse). The recording data is recorded for each predetermined area (for example, address unit) on the track while changing the position dTe) at which the recording ends.

The recording / reproducing apparatus 100 reproduces the recorded data and detects a length error or a phase error. The information recording medium controller 14 compares the detected length error or phase error with the length error target value or phase error target value stored in the error target value storage unit 15 and is closest to the error target value. Determine the recording pulse conditions.
By the above operation, the recording parameter is adjusted so that the length error and the phase error become the respective error target values, so that the error rate of the recording information is reduced, and the clock generation in the PLL circuit is stable and the recording parameter condition is stable. Recording can be performed.
FIG. 19 shows a second recording / reproducing apparatus 200 in the embodiment of the present invention. In addition to the components of the recording / reproducing apparatus 100 shown in FIG. 1, the recording / reproducing apparatus 200 further includes a jitter detector 19. In the recording / reproducing apparatus 200 shown in FIG. 19, the same components as those of the recording / reproducing apparatus 100 are denoted by the same reference numerals, and description thereof is omitted.
In FIG. 19, the PLL circuit 7 detects the phase difference between the digital signal and the reproduction clock signal in the PLL circuit 7 based on the digital signal output from the A / D converter 6, and the phase difference is detected by the jitter detector 19. Output to. The jitter detector 19 calculates a jitter value based on a phase difference distribution obtained by integrating the phase difference output from the PLL circuit 7 for a predetermined time or a predetermined number of times, and the jitter value is sent to the information recording medium controller 14. Note that edge position deviation may be used instead of the jitter value.

The operation in which the information recording medium controller 14 in the recording / reproducing apparatus 200 adjusts the length error and phase error during recording pulse adjustment to each error target value stored in the error target value storage unit 15 is shown in FIG. Since it is the same as the recording / reproducing apparatus 100, the description of the recording pulse adjustment is omitted. Here, an operation in which the information recording medium controller 14 in the recording / reproducing apparatus 200 determines the error target value stored in the error target value storage unit 15 will be described.
First, the information recording medium controller 14 acquires recording pulse information written on the optical disc and determines it as an initial value of a recording pulse condition for laser emission. Next, the information recording medium controller 14 records the recording data while changing an arbitrary recording parameter (for example, the top pulse width of the 3T mark) for each predetermined area (for example, address unit) on the track. It instructs the recording compensation circuit 17, the laser drive circuit 18, and the optical head unit 2.
Note that the recording data used at this time is not limited to the recording data used when adjusting the length error or the phase error, and may be, for example, a random signal in which the appearance frequency of the shortest mark is high. In this case, since the index value to be detected is jitter, recording data in which the jitter value changes significantly with changes in the recording pulse is desirable.

The recording / reproducing apparatus 200 reproduces the area where the recording data is recorded, and the jitter detector 19 detects the jitter corresponding to each recording parameter. Subsequently, the information recording medium controller 14 determines a recording parameter that minimizes jitter. As described above, the information recording medium controller 14 determines the recording parameter that minimizes the jitter while updating the recording parameter that minimizes the jitter to the next initial value for all the recording parameters. The finally determined recording parameter is the optimum recording parameter for jitter.
Further, the information recording medium controller 14 instructs the recording compensation circuit 17, the laser driving circuit 18, and the optical head unit 2 to record the recording data on the track of the optical disc with the recording parameter optimum for the jitter.
The recording data used at this time is preferably the same as the recording data used when adjusting the length error or phase error. This is to prevent the length error and the phase error from becoming different detection values due to, for example, a change in DSV or a slice level in binarization processing due to a difference in recording data. Another reason is to prevent a recording pattern that is not detected from occurring.
The recording / reproducing apparatus 200 reproduces the area recorded with the optimum recording parameter for jitter, and the recording information error calculation unit 13 detects the length error Dlj and the phase error Dpj. The length error Dlj and the phase error Dpj are a length error and a phase error that are optimum for jitter. In addition, the length error and the phase error are 0.0 in the recording parameter that is optimal for the maximum likelihood decoding method. Therefore, the information recording medium controller 14 can determine the length error target value as 0.0 to Dlj (for example, an intermediate value) and the phase error target value as 0.0 to Dpj (for example, an intermediate value). it can.

As described above, by providing the jitter detection unit 19 in the recording / reproducing apparatus, for example, the error target value in the manufacturing process of the recording / reproducing apparatus or the like is stored, or the error target value is newly stored in the new optical disk later. It is not necessary to reduce the number of work steps.
In the above embodiment, the PLL circuit 7 in the recording / reproducing apparatus 200 detects the phase difference between the digital signal and the reproduction clock signal in the PLL circuit 7 based on the digital signal output from the A / D converter 6. . However, the PLL circuit 7 may be a circuit (including a binarization process) that processes an analog signal instead of a circuit that processes a digital signal. For example, it is the third recording / reproducing apparatus 300 in the embodiment of the present invention shown in FIG.
The recording / reproducing apparatus 300 further includes a comparator 20 in addition to the components of the recording / reproducing apparatus 200 shown in FIG. In the recording / reproducing apparatus 300 shown in FIG. 20, the same components as those of the recording / reproducing apparatus 200 are denoted by the same reference numerals, and description thereof is omitted. The PLL circuit 7 includes at least a phase comparator 21, an LPF 22, and a VCO 23.
In the recording / reproducing apparatus 300 in FIG. 20, the reproduction signal output from the waveform equalizer 5 is an analog signal and is binarized by the comparator 20. Normally, the threshold value of the comparator 20 is feedback controlled so that the integration result of the binarized output becomes zero. The phase comparator 21 obtains the phase difference between the binarized output and the recovered clock signal. The phase difference is averaged by the LPF 22 and becomes the control voltage of the VCO 23. Feedback control is applied so that the phase difference output from the phase comparator 21 is always zero. As described above, the PLL circuit 7 can binarize the analog signal to detect the phase difference, and can output the phase difference to the jitter detector 19.

In the above embodiment, the recording / reproducing apparatus 100 in FIG. 1 cannot detect jitter. However, the recording / reproducing apparatus 100 can detect jitter by outputting a reproduction signal from the information recording medium to the outside of the apparatus. For example, the fourth recording / reproducing apparatus 400 in the embodiment of the present invention shown in FIG.
The recording / reproducing apparatus 400 includes a jitter external calculation unit 105 in addition to the components of the recording / reproducing apparatus 100 shown in FIG. In the recording / reproducing apparatus 400 shown in FIG. 21, the same components as those of the recording / reproducing apparatus 100 are denoted by the same reference numerals, and description thereof is omitted. The jitter external calculation unit 105 includes a waveform equalizer 24 and a jitter meter 25.
In FIG. 21, the recording / reproducing apparatus 400 outputs the analog reproduction signal output from the optical head unit 2 to the waveform equalizer 24 of the jitter external calculation unit 105. The waveform equalizer 24 amplifies and AC-couples the analog reproduction signal, and then performs gain adjustment and waveform equalization. Further, the waveform equalizer 24 binarizes the waveform equalized reproduction signal and outputs the binarized signal to the jitter meter 25. In addition, a reproduction clock signal is generated from an analog reproduction signal input to the waveform equalizer 24 by a PLL circuit (not shown) included in the waveform equalizer 24 and is output to the jitter meter 25. The jitter meter 25 calculates jitter based on a phase difference distribution obtained by integrating the phase difference between the binarized signal output from the waveform equalizer 24 and the recovered clock signal for a predetermined time or a predetermined number of times.

As described above, it is possible to detect jitter by outputting a reproduction signal from the recording / reproducing apparatus 100 shown in FIG. 1 to the outside of the apparatus. Therefore, by referring to the jitter value calculated by the jitter external calculation unit 105, the user can confirm the recording parameter that minimizes the jitter and determine the recording parameter. Unlike the recording / reproducing apparatus 200 and the recording / reproducing apparatus 300, the recording / reproducing apparatus 400 detects jitter outside the apparatus, so there is no need to include the jitter detector 19 inside the apparatus, thereby reducing the cost of the recording / reproducing apparatus. Can be planned.
The signal output to the jitter external calculation unit is not limited to the analog reproduction signal output from the optical head unit 2, and may be any other signal such as the output signal of the waveform equalizer 5 as long as the signal can detect jitter. This signal may be output.
An example of results using the recording / reproducing apparatus according to the present invention will be described. Here, the recording / reproducing apparatus is a recording / reproducing apparatus 400 shown in FIG. The optical disc is a commercially available BD-RE, and information such as recording power and recording pulse conditions used is information written in the disc. The wavelength of the optical head was 405 nm, and the numerical aperture of the lens was 0.85. The recording code was a (1, 7) modulation code having a minimum polarity inversion interval of 2, and the equalization method was PR (1, 2, 2, 1) equalization. The channel clock period Tclk was 66 MHz. In addition, as a waveform equalizer and a jitter meter in the jitter external calculation unit, a commercially available limit equalizer and time interval analyzer were used in order to evaluate BD-RE. Also, assuming that the index indicating the quality of the reproduction signal is PRML error index M from (Equation 6), the PRML error index M is

Can be defined as However, d ² _min is the square of the minimum value of the Euclidean distance, and is 10 in the combination of the modulation code and the PRML system of this embodiment. Further, it is assumed that the average value Pave ₁₀ in (Expression 6) is 0.
Here, test recording was performed by changing the target length of the 3T mark, and the edge shift of the start / end part of the recording signal was detected based on the reliability of the maximum likelihood decoding result to adjust the recording pulse. Furthermore, using the adjusted recording pulse conditions, the random signal including the adjacent track was overwritten 10 times to reproduce the recording track. FIG. 29 shows an example of the recording / reproducing result under the recording pulse condition obtained by changing the length error target value of the 3T mark. The solid line with a circle is the value of the PRML error index M, and the solid line with a triangle is the value of jitter. Further, both the PRML error index M and the jitter have a better signal quality of the recording signal as the detected value is smaller. Further, when the length error target value is a negative value, the length of the recording mark is shortened.
In FIG. 29, since the recording pulse is adjusted using the maximum likelihood decoding result, the PRML error index M is the minimum value when the length error target value is set to zero. However, with regard to jitter, it can be seen that the jitter value decreases as the 3T mark length error target value becomes negative, that is, the recording mark becomes shorter.

When the 3T mark length error target value was set to 0, the PRML error index value M was 8.5% and the jitter was 7.8%. When the 3T mark length error target value was set to −1.32, the PRML error index value M was 8.7% and the jitter was 7.3%. That is, it can be seen that the jitter is reduced by 0.5% with respect to the 0.2% increment of the PRML error index value M. Even if the changes of both index values are compared in proportion, the effect of the present invention for adjusting the recording pulse with the length error target value other than 0 can be confirmed. When the recording pulse is adjusted with the 3T mark length error target value further negative, the jitter value tends to decrease further, but the PRML error index value M tends to increase slightly. It is desirable to set the length error target value used when adjusting the value between the length target value at which the jitter is optimal (for example, −1.32).
FIG. 23 shows the procedure for adjusting the shape of the recording signal in the recording / reproducing apparatus of the present embodiment. Hereinafter, the procedure for adjusting the shape of the recording signal will be described step by step with reference to FIGS. This procedure for adjusting the shape of the recording signal is performed on the information recording medium 1 by the recording / reproducing apparatus.
Step 2301: Obtain information related to the shape of a recording signal. The information related to the shape of the recording signal is information described in the information recording medium 1 or information stored in the recording / reproducing apparatus.

Step 2302: Move to an area for test recording.
Step 2303: It is determined whether or not the adjustment of all the recording parameters is completed. If it is determined that all the recording parameters have been adjusted (Yes), the adjustment of the shape of the recording signal is ended. If it is determined that adjustment of all recording parameters has not been completed (No), the process proceeds to step 2304 to repeat the adjustment of recording parameters. The recording parameter is a parameter (for example, top pulse width Ttop) that forms the shape of the recording signal.
Step 2304: Test test patterns are recorded under different recording conditions. The test recording pattern may be a fixed pattern or a random signal.
Step 2305: Information is reproduced from the recording area for each recording condition.
Step 2306: Perform signal processing of the reproduction signal. A detailed description of step 2306 will be given later.
Step 2307: It is determined whether the optimum recording parameter has been determined. If it is determined that the optimum recording parameter has been determined (Yes), the process proceeds to step 2303 in order to adjust other recording parameters. If it is determined that the optimum recording parameter has not been determined (No), the process proceeds to step 2304 in order to continue searching for the optimum recording parameter.

FIG. 24 is a detailed procedure of signal processing of the reproduction signal in FIG. Hereinafter, with reference to FIG. 24, a detailed procedure of signal processing of the reproduction signal will be described step by step.
Step 2401: A digital signal is generated from a reproduction signal which is an analog signal.
Step 2402: Shape the digital signal waveform.
Step 2403: A binary signal is generated by maximum likelihood decoding.
Step 2404: The reliability of the maximum likelihood decoding result is calculated from the waveform-shaped digital signal and the binarized signal.
Step 2405: The edge shift of the start / end part of the recording signal is detected based on the reliability of the maximum likelihood decoding result.
Step 2406: Calculate length error and phase error of the recording signal.
Step 2407: Recording parameters are determined based on the length error and phase error of each recording condition, and the process ends.
FIG. 25 is a procedure for obtaining a length error and a phase error for each recording pattern with respect to FIG. Hereinafter, with reference to FIG. 25, the detailed procedure of the signal processing of the reproduction signal will be described step by step.

Step 2501: A digital signal is generated from a reproduction signal which is an analog signal.
Step 2502: A digital signal waveform is generated.
Step 2503: A binarized signal is generated by maximum likelihood decoding.
Step 2504: The reliability of the maximum likelihood decoding result is calculated from the waveform-shaped digital signal and the binarized signal.
Step 2505: Based on the reliability of the maximum likelihood decoding result, the edge shift of the start / end part of the recording signal is detected.
Step 2506: Assign edge shifts at the beginning and end of the recording signal for each recording pattern.
Step 2507: A length error and a phase error for each recording pattern are calculated.
Step 2508: Recording parameters are determined by the length error and phase error for each recording pattern under each recording condition, and the process ends.
FIG. 26 is a detailed procedure for determining recording parameters for each recording condition in step 2407 in FIG. 24 and step 2508 in FIG. In the following, with reference to FIG. 26, a detailed procedure for determining recording parameters for each recording condition will be described step by step.

Step 2601: It is determined whether the shape of the recording signal to be adjusted is an adjustment related to the length. If it is determined that the shape of the recording signal to be adjusted is an adjustment related to the length (Yes), the process proceeds to step 2602 to perform a process related to the length error. If it is determined that the shape of the recording signal to be adjusted is not an adjustment related to the length (No), the process proceeds to step 2605 to perform a process related to the phase error.
Step 2602: A length error target value is acquired. The length error target value is stored in the recording / reproducing apparatus.
Step 2603: It is determined whether the length error target value is included in the length error of each recording condition. If the length error target value is included in the length error of each recording condition (Yes), the process proceeds to step 2604 to determine a recording parameter. If the length error target value is not included in the length error of each recording condition (No), the recording parameter determination process is ended in order to search for a different recording condition. When searching for different recording conditions, the determination in step 2307 in FIG.
Step 2604: The recording condition with the closest length error target value is determined as the recording parameter, and the process ends.

Step 2605: A phase error target value is acquired. The phase error target value is stored in the recording / reproducing apparatus.
Step 2606: It is determined whether the phase error target value is included in the length error of each recording condition. If the phase error target value is included in the phase error of each recording condition (Yes), the process proceeds to step 2607 to determine the recording parameter. If the phase error target value is not included in the phase error of each recording condition (No), the recording parameter determination process is terminated to search for a different recording condition. When searching for different recording conditions, the determination in step 2307 in FIG.
Step 2607: The recording condition with the closest phase error target value is determined as the recording parameter, and the process is terminated.
Next, FIG. 27 shows a procedure for adjusting the shape of the recording signal using both the jitter and maximum likelihood decoding methods in the recording / reproducing apparatus of the present embodiment. Hereinafter, the procedure for adjusting the shape of the recording signal will be described step by step with reference to FIG. This procedure for adjusting the shape of the recording signal is performed on the information recording medium 1 by the recording / reproducing apparatus.
Step 2701: Adjust the shape of the recording signal by jitter. The adjustment of the recording signal with respect to the jitter has been described in the prior art and will not be described in detail, but the jitter value or the difference between the average value of the distribution of the phase error Δt and the ideal edge position, or The shape of the recording signal is adjusted so that the accumulated absolute value of the phase error Δt approaches zero.

Step 2702: A length error target value and a phase error target value are determined from the adjustment result of the shape of the recording signal due to jitter. A detailed description of step 2702 will be described later.
Step 2703: The shape of the recording signal is adjusted by the length error and the phase difference calculated from the reliability of the maximum likelihood decoding result. Note that step 2705 is the same as the adjustment processing described in FIG.
FIG. 28 is a detailed procedure for determining the length error target value and the phase error target value in FIG. The detailed procedure for determining the length error target value and the phase error target value will be described step by step with reference to FIG.
Step 2801: Information is recorded on the information recording medium in the form of a recording signal adjusted by jitter.
Step 2802: Information is reproduced from the recording area.
Step 2803: A digital signal is generated from the reproduction signal which is an analog signal.
Step 2804: The digital signal waveform is shaped.
Step 2805: A binary signal is generated by maximum likelihood decoding.
Step 2806: The reliability of the maximum likelihood decoding result is calculated from the waveform-shaped digital signal and the binarized signal.

Step 2807: The edge shift of the start / end part of the recording signal is detected based on the reliability of the maximum likelihood decoding result.
Step 2808: Assign edge shifts at the beginning and end of the recording signal for each recording pattern.
Step 2809: A length error Dlj and a phase error Dpj are calculated for each recording pattern.
Step 2810: A length error target value Dlt and a phase error target value Dpt are determined. Note that at least one of the length error target value Dlt and the phase error target value Dpt is determined as an error target value other than 0 for at least one or more start / end patterns. Further, the length error target value Dlt is determined as 0 <Dlt <Dlj, or the phase error target value Dpt is determined as 0 <Dpt <Dpj. In this embodiment, it is desirable that the length error target value Dlt is an error target value other than 0 and the phase error target value Dpt is 0.
Step 2811: The length error target value Dlt and the phase error target value Dpt are stored. The length error target value Dlt and the phase error target value Dpt are stored in the recording / reproducing apparatus. Moreover, you may record inside an information recording medium.

Note that the processing procedure of the present invention may have any procedure as long as the above steps can be executed. Further, the present invention may be a recording / reproducing program for executing the functions of the recording / reproducing apparatus in the present embodiment. The recording / reproducing program may be stored in the recording / reproducing apparatus in the present embodiment. The recording / reproducing program may be stored in advance in storage means included in the recording / reproducing apparatus when the recording / reproducing apparatus is shipped. Alternatively, the recording / reproducing program may be stored in the storage means after the recording / reproducing apparatus is shipped. For example, the user may download a recording / playback program from a specific website on the Internet for a fee or free of charge, and install the downloaded recording / playback program in the recording / playback apparatus. When the recording / reproducing program is recorded on a computer-readable information recording medium such as a flexible disk, a CD-ROM, or a DVD-ROM, the recording / reproducing program is installed in the recording / reproducing apparatus using the input device. May be. The installed recording / reproducing program is stored in the storage means.
The embodiments of the present invention have been described above with reference to the drawings.
In this embodiment, in the adjustment of the recording mark length error, the start edge position and the end edge position are simultaneously changed. The length error may be adjusted. This is effective when the sensitivity at which the edge position of the recording mark changes differs between the start and end portions when the start edge position and the end edge change. For example, for an optical disc in which a change in recording mark is larger due to changes in dTtop and Ttop that adjust the start edge position than dTe that adjusts the end edge position, the length error of the recording mark is first at the start edge. Adjusted by position. At this time, if the length error of the recording mark becomes the length error target value, it is not necessary to adjust the end edge position. Further, the end edge position may be changed as a fine adjustment of the recording mark length error or phase error.

In this embodiment, the phase error target value is set to 0. However, the phase error target value is not necessarily set to 0, and the phase error target value may be set to other than 0 as necessary. For example, it has been found that the phase of a recording mark in a specific recording pattern (for example, 5T mark in a 2 space-5T mark-2T space pattern) affects the length and phase of the recording marks before and after the recording pattern. In such a case (for example, an optical disc having different thermal interference depending on the combination of recording marks and spaces), the influence can be suppressed by moving the phase error target value other than 0, that is, by moving the recording marks of the recording pattern back and forth. .
In this embodiment, the lengths of recording marks and spaces of 5T or more are combined into one, but they may be set for recording marks and spaces from 5T to the longest mark.
In this embodiment, the change of the recording pulse is set to the constant time interval Δt, but it is not always necessary to set the constant time interval, and the time interval may be changed. For example, the present invention can be applied when a change in length error or phase error has a nonlinear relationship with a change in recording pulse. Further, it is not necessary to record / reproduce a plurality of recording conditions at a time. Recording / reproduction may be performed under one recording condition, and the recording condition may be changed according to the result of the length error or phase error. For example, when recording / reproduction is performed with the recording pulse condition described on the optical disc as an initial condition, and it is determined that the detected length error is longer than the target length error value, the next trial recording is performed. The recording pulse condition to be set is set so that the length of the recording mark is shortened. As described above, the method of adjusting the recording condition to the error target value according to the recording / reproducing result increases the adjustment time. As a result, the recording method to be used is more than the method of recording a plurality of recording conditions at a time. The area can be minimized. This is particularly effective for an optical disc in which the recording area and the number of times of recording are limited, such as a write-once optical disc such as a DVD-R. Therefore, whether to adjust the recording parameters by recording at a time under a plurality of recording conditions or to adjust the recording parameters based on the recording / reproduction result of one recording condition depends on the type of optical disc. It doesn't matter.

  Furthermore, the length error target value and the phase error target value in this embodiment are not fixed to a constant value, depending on the type of optical disk such as BD-RE and DVD-RAM, the recording capacity, and the recording layer in the multilayer disk. It does not matter if it is set. In addition, the frequency characteristics of the waveform equalizer when detecting jitter may differ depending on the type of optical disk and the recording capacity. In this case, the shape of the recording mark is not a little different. Therefore, it is desirable that the length error target value and the phase error target value are set in accordance with the difference in the type and recording capacity of the optical disc and the recording layer in the multilayer disc. Further, the length error target value and the phase error target value may be set for each of the corresponding recording speed of the optical disc and the difference of the disc manufacturer. As described above, the length error target value and the phase error target value are set for each optical disc difference by previously storing the error target value corresponding to each condition in the recording information error calculation unit. It is feasible. Information on the recording medium (hereinafter referred to as recording medium information) relating to the type, recording capacity, multilayer information, etc. of the optical disk is recorded inside the optical disk (not shown). Furthermore, since the recording / reproducing apparatus can generally acquire the recording medium information, it is possible to easily set an error target value corresponding to the difference in the recording medium information. As a result, the recording parameters can be adjusted with higher accuracy according to differences in the type and recording capacity of the optical disc, the recording layer in the multilayer disc, and the quality of the reproduction signal can be improved.

In the above embodiment, the case where PR (1, 2, 2, 1) equalization is performed using a code having a minimum polarity inversion interval of 2 as a recording code has been described, but the present invention is not limited to this. For example, in the case where the minimum polarity inversion interval is 2 such as a recording code (1, 7) modulation code, the above embodiment can be applied, and the minimum polarity inversion interval such as 8-16 modulation code used for DVD is 3 In this case, there are six states at time k due to PR (1, 2, 2, 1) equalization, and a state transition rule that restricts eight possible state transitions to the six states at time k + 1. By using it, the present invention can be implemented. Therefore, when a combination of a code having a minimum polarity reversal interval of 3 and PR (C0, C1, C1, C0) equalization is used, a code having a minimum polarity reversal interval of 2 or 3 and PR (C0, C1, The present invention can also be applied when a combination of (C0) equalization is used, or when a combination of a code having a minimum polarity inversion interval of 2 or 3 and PR (C0, C1, C2, C1, C0) equalization is used. C0, C1, and C2 are arbitrary positive numbers.
The information recording medium in this embodiment is not limited to an optical disk such as a CD, DVD, or BD, but a magneto-optical medium such as MO (Magneto-Optical Disc) or a recording code (0 or 1) of a digital signal is continuous. The present invention can also be applied to an information recording medium in which information is recorded by changing the length or phase of information (recording marks and spaces in this embodiment) formed according to the polarity interval, which is the length to be recorded.

If there is an information recording medium in which the length error or the phase error is other than 0 as a result of recording and reproducing the optimum recording parameter for the maximum likelihood decoding method using the present invention, the detected length error is Dlp (a value other than 0) or the phase error is Dpp (a value other than 0). Further, as a result of reproducing the recording mark formed on the information recording medium with the recording parameters adjusted so as to optimize the jitter, the detected length error is Dlj (a value other than 0) and the phase error is Dpj ( If the value is a value other than 0), the present invention also includes setting the length error target value Dlt between Dlp and Dlj and the phase error target value Dpt between Dpp and Dpj.
The present invention is not limited to use only when adjusting the pulse shape of a recording pulse in a recording / reproducing apparatus. Information relating to a recording pulse obtained by the present invention, a length error target value or a phase error target value can be used as an information recording medium. It may be recorded inside. In this case, since the length error target value or the phase error target value for the information recording medium can be obtained by reproducing the information recording medium on which the length error target value or the phase error target value is recorded. It is not necessary to store error target values for various information recording media in the error target value storage unit, and the circuit scale of the recording / reproducing apparatus can be reduced.
Further, a part of the recording / reproducing apparatus of the present invention is a one-chip LSI (semiconductor integrated circuit) or one of them as a recording signal adjusting apparatus for adjusting the shape of a recording signal for recording information on an information recording medium. It can be manufactured as a function of parts. When a part of the recording / reproducing apparatus is manufactured as a one-chip LSI, the signal processing time for adjusting the recording parameters can be greatly shortened. Each part of the recording / reproducing apparatus may be independently manufactured as an LSI.

In the case of FIG. 1, the recording signal adjustment apparatus includes, for example, a pattern detection circuit 11, an edge shift detection circuit 12, a recording information error calculation unit 13, an information recording medium controller 14, and an error target value storage unit 15. Is provided. The recording signal adjusting device receives, for example, information on the shape of the recording signal, a digital signal, and a decoding result of the digital signal. Compared with the adjustment unit 104 in FIG. 1, the recording signal adjustment apparatus needs information on the shape of the recording signal. This is because the recording signal adjusting device itself does not execute the recording operation, and therefore there is no information relating to the shape of the recording signal corresponding to the digital signal, and the shape of the recording signal cannot be adjusted. Therefore, information regarding the shape of the recording signal is input to the information recording medium controller 14.
As described above, the recording signal adjustment apparatus can execute the same operation as the adjustment unit 104 in FIG. 1 by inputting a specific signal, and can change the shape of the recording signal for recording information on the information recording medium. Can be adjusted. For example, by causing the information recording medium controller 14 to further input recording medium information, the length error target value Dlt corresponding to each optical disk stored in the error target value storage unit 15 or the phase error target value Dpt can be set. Further, similarly to the recording signal adjustment apparatus described above, the present invention can also be applied to a recording signal adjustment method that is a method for adjusting the shape of a recording signal and a recording signal adjustment program that is a program for adjusting the shape of a recording signal. .

Finally, in the present embodiment, the start / end edge of the recording signal is assigned to each recording pattern, and the edge shift at the start / end portion of the recording signal corresponding to the recording pattern is detected based on the reliability of the maximum likelihood decoding result, Based on the edge shift, a length error Dl that is an error with respect to the length of a recording signal for each recording pattern or a phase error Dp that is an error with respect to a phase, or both a length error Dl and a phase error Dp are calculated, The length error Dl or the phase error Dp of at least one recording pattern in the length error Dl or the phase error Dp, or both the length error Dl and the phase error Dp are set as error target values other than 0. An example of adjusting the signal shape was shown.
As a modification of the present embodiment, based on the result of the phase difference between the binarized signal and the reproduction clock signal described with reference to FIG. 9, the edge position shift (phase error) of the start / end portion of the recording signal corresponding to the recording pattern is performed. The average value of the distribution of Δt or the cumulative value of the absolute value of the phase error Δt) is detected, and based on the edge position deviation, the length error D1 or phase which is an error with respect to the length of the recording signal for each recording pattern The phase error Dp, which is an error with respect to, or both the length error Dl and the phase error Dp are calculated, and the length error Dl or the phase error Dp of at least one recording pattern in the length error Dl or the phase error Dp is calculated. Or the length error Dl and the phase error Dp are both error target values other than 0, and the shape of the recording signal can be adjusted. However, the binarized signal at this time is a decoding result, and the reproduction clock signal corresponds to a digital signal. Assuming that the length error and the phase error detected as a result of reproducing the recording mark formed by the recording parameter obtained by the maximum likelihood decoding method are Dlp and Dpp, the length error target value Dlt is 0 <Dlt < Dlp or the phase error target value Dpt is 0 <Dpt <Dpp.

Therefore, in the case where the edge shift of the start / end portion of the recording signal is detected based on the reliability of the maximum likelihood decoding result, the edge shift is regarded as a positional shift at the start / end portion of the recording signal, and the binarization described in FIG. In the case where an edge position shift at the start / end portion of the recording signal is detected based on the result of the phase difference between the signal and the reproduction clock signal, the edge position shift can be applied to the present invention as a position shift at the start / end section of the recording signal. .
As described above, the present invention is based on the digital signal generated from the signal reproduced from the information recording medium and the decoding result, and the positional deviation from the ideal edge position at the start / end portion of the recording signal according to the recording pattern. And a length error Dl that is an error with respect to the length of the recording signal for each recording pattern or a phase error Dp that is an error with respect to the phase, or a length based on the positional deviation of the start and end portions of the recording signal. The error Dl and the phase error Dp are calculated together, and the length error Dl or the phase error Dp of at least one recording pattern in the length error Dl or the phase error Dp, or the length error Dl and the phase error Dp are calculated. In both cases, the shape of the recording signal with respect to the recording pattern is adjusted as an error target value other than zero. By this adjustment, it is possible to perform recording under recording parameter conditions in which the error rate of recording information is reduced and the clock generation in the PLL circuit is stable, and a more stable recording / reproducing system can be provided.

  The present invention provides various information recording media for recording data signals by laser light, electromagnetic force, etc., such as DVD-RAM, BD-RE, and other information recording media. The present invention can be applied to other uses such as a recording / reproducing apparatus to be used, for example, a DVD drive, a DVD recorder, a BD recorder, and other devices, which are used in a recording condition adjustment stage.

The figure which shows the 1st recording / reproducing apparatus in embodiment of this invention The figure which shows the state transition rule determined from the recording code and the equalization system PR (1, 2, 2, 1) whose minimum polarity inversion interval is 2 in the embodiment of the present invention The figure which shows the trellis figure and state transition example which are decided from the restrictions of PR (1, 2, 2, 1) equalization that the minimum polarity reversal space | interval is 2 in embodiment of this invention Schematic diagram of Pa-Pb distribution showing reliability of decoding result in the embodiment of the present invention The figure which shows the specific 8 pattern in embodiment of this invention The figure which shows the correlation with the shift | offset | difference of a reproduction | regeneration waveform and a recording mark in Pattern1 (when path A is correct) of the specific patterns in the embodiment of the present invention. The figure which shows the correlation with the shift | offset | difference of a reproduction | regeneration waveform and a recording mark in Pattern1 (when path B is correct) of the specific patterns in the embodiment of the present invention. The figure which shows the correlation with the shift | offset | difference of a reproduction | regeneration waveform and a recording mark in the combination of Pattern1 (when path B is correct) and Pattern5 (when path B is correct) among the specific patterns in the embodiment of the present invention. Explanatory drawing of the jitter detected from the reproduction signal waveform of the recording mark in the embodiment of the present invention Explanatory drawing of the length error target value in the embodiment of the present invention The figure which shows the recording pulse with respect to each recording mark in embodiment of this invention The figure which shows which of the specific 8 patterns detects the recording parameter which needs the optimization in embodiment of this invention The figure which shows the recording pattern which detects the length error and phase error in embodiment of this invention The figure which shows the change of the length of the recording mark with respect to the change of the recording pulse in embodiment of this invention The figure which shows the change of the length error of the recording mark detected with respect to the change of the recording pulse in embodiment of this invention The figure which shows the change of the phase of the recording mark with respect to the change of the recording pulse in embodiment of this invention The figure which shows the change of the phase error of the recording mark detected with respect to the change of the recording pulse in embodiment of this invention The figure which shows the recording pattern for recording parameter adjustment in embodiment of this invention The figure which shows the 2nd recording / reproducing apparatus in embodiment of this invention The figure which shows the 3rd recording / reproducing apparatus in embodiment of this invention The figure which shows the 4th recording / reproducing apparatus in embodiment of this invention A diagram showing a conventional recording / reproducing apparatus Flow chart showing the procedure for adjusting the shape of the recording signal Flow chart showing detailed procedure of signal processing of reproduction signal FIG. 24 is a flowchart showing a procedure for obtaining a length error and a phase error for each recording pattern. A flowchart showing a detailed procedure for determining a recording parameter for each recording condition Flowchart showing a procedure for adjusting the shape of a recording signal using both the jitter and maximum likelihood decoding methods Flowchart showing a detailed procedure for determining a length error target value and a phase error target value The figure which shows the example of the recording / reproducing result by the recording pulse conditions calculated | required by changing the length error target value of 3T mark

Explanation of symbols

1, 26 Information recording medium 2, 27 Optical head part 3, 28 Preamplifier 4, 29 AGC
5, 30 Waveform equalizer 6, 31 A / D converter 7, 32 PLL circuit 8, 33 Shaping unit 9, 34 Maximum likelihood decoding unit 10, 35 Reliability calculation unit 11, 36 Pattern detection unit 12, 37 Edge shift Detection circuit 13 Recording information error calculation unit 14, 38 Information recording medium controller 15 Error target value storage unit 16, 39 Pattern generation circuit 17, 40 Recording compensation circuit 18, 41 Laser drive circuit 19 Jitter detection unit 20 Comparator 21 Phase comparator 22 LPF
23 VCO
24 Waveform equalizer 25 Jitter meter

Claims (30)

A reproduction unit that generates a digital signal from an analog signal indicating information reproduced from an information recording medium;
A decoding unit for decoding the digital signal;
An adjusting unit that adjusts a shape of a recording signal for recording the information on the information recording medium based on the digital signal and a decoding result;
A recording / reproducing apparatus comprising a recording unit for recording the information on the information recording medium based on the adjusted shape of the recording signal,
The adjustment unit, a pattern detection circuit for generating a pulse signal for assigning the start and end edges of the recording signal for each recording pattern;
A misregistration detection circuit for detecting misregistration from an ideal edge position at a start / end portion of a recording signal corresponding to the recording pattern by the digital signal, the decoding result, and the pulse signal;
Based on the positional deviation of the start and end portions of the recording signal, the length error Dl that is an error with respect to the length of the recording signal for each recording pattern or the phase error Dp that is an error with respect to the phase, or the length error Dl and the phase A recording information error calculation unit for calculating the error Dp together;
The length error Dl or the phase error Dp of the at least one recording pattern in the length error Dl or the phase error Dp, or both the length error Dl and the phase error Dp are set as error target values other than 0. A recording / reproducing apparatus for adjusting a shape of the recording signal with respect to a pattern.   The adjustment unit includes a length error target value Dlt, which is an error target value of the length error Dl for each recording pattern, or a phase error target value Dpt, which is an error target value of the phase error Dp, or the length error target. An error target value storage unit that stores both the value Dlt and the phase error target value Dpt is further provided, and the length error D1 for each recording pattern is the length error target value Dlt or the phase error Dp for each recording pattern is the phase. The shape of the recording signal with respect to the recording pattern is adjusted so that the error target value Dpt is reached, or the length error Dl becomes the length error target value Dlt and the phase error Dp becomes the phase error target value Dpt. The recording / reproducing apparatus according to claim 1, wherein:   The recording / reproducing apparatus according to claim 2, wherein the length error target value Dlt of the at least one recording pattern is other than 0 and the phase error target value Dpt is 0.   The decoding unit is a maximum likelihood decoding unit that performs maximum likelihood decoding of the digital signal, and reproduces information recorded in advance on the information recording medium in the form of a recording signal adjusted to minimize jitter, The calculated length error is Dlj and the phase error is Dpj, and the length error target value Dlt is 0 <Dlt <Dlj, or the phase error target value Dpt is 0 <Dpt <Dpj, The recording / reproducing apparatus according to claim 2.   The recording / reproducing apparatus according to claim 2, wherein the length error target value Dlt or the phase error target value Dpt varies depending on a difference in recording medium information recorded on the information recording medium. A digital signal is generated from an analog signal indicating information reproduced from an information recording medium,
Decoding the digital signal;
Based on the digital signal and the decoding result, adjust the shape of the recording signal for recording the information on the information recording medium,
A recording / reproducing method for recording the information on the information recording medium based on the adjusted shape of the recording signal,
The adjustment of the shape of the recording signal generates a pulse signal for assigning the start and end edges of the recording signal for each recording pattern,
Detecting a positional deviation from an ideal edge position at the start / end part of the recording signal according to the recording pattern by the digital signal, the decoding result, and the pulse signal,
Based on the positional deviation of the start and end portions of the recording signal, the length error Dl that is an error with respect to the length of the recording signal for each recording pattern or the phase error Dp that is an error with respect to the phase, or the length error Dl and the phase Calculate error Dp together,
The length error Dl or the phase error Dp of the at least one recording pattern in the length error Dl or the phase error Dp, or both the length error Dl and the phase error Dp are set as error target values other than 0. A recording / reproducing method comprising adjusting a shape of the recording signal with respect to a pattern.   In the adjustment of the shape of the recording signal, a length error target value Dlt in which the length error Dl for each recording pattern is the target value of the length error or the phase error Dp for each recording pattern is the target value of the phase error. The shape of the recording signal with respect to the recording pattern is adjusted so that the phase error target value Dpt or the length error Dl becomes the length error target value Dlt and the phase error Dp becomes the phase error target value Dpt. The recording / reproducing method according to claim 6, wherein:   8. The recording / reproducing method according to claim 7, wherein the length error target value Dlt of the at least one recording pattern is other than 0 and the phase error target value Dpt is 0.   The decoding result is a result of maximum likelihood decoding of the digital signal, and is calculated by reproducing information recorded in advance on the information recording medium in the form of a recording signal adjusted to minimize jitter. 8. The length error is Dlj and the phase error is Dpj, and the length error target value Dlt is 0 <Dlt <Dlj, or the phase error target value Dpt is 0 <Dpt <Dpj. The recording / reproducing method described in 1.   8. The recording / reproducing method according to claim 7, wherein the length error target value Dlt or the phase error target value Dpt varies depending on the recording medium information recorded on the information recording medium. Generating a digital signal from an analog signal indicating information reproduced from an information recording medium;
Decoding the digital signal;
Adjusting a shape of a recording signal for recording the information on the information recording medium based on the digital signal and a decoding result;
A recording / reproducing program for causing a computer to execute a recording / reproducing process for recording the information on the information recording medium based on the adjusted shape of the recording signal,
The step of adjusting the shape of the recording signal includes generating a pulse signal for assigning the start and end edges of the recording signal for each recording pattern;
Detecting a displacement from an ideal edge position at a start / end portion of a recording signal corresponding to the recording pattern by the digital signal, a decoding result, and the pulse signal;
Based on the positional deviation of the start and end portions of the recording signal, the length error Dl that is an error with respect to the length of the recording signal for each recording pattern or the phase error Dp that is an error with respect to the phase, or the length error Dl and the phase Including calculating the error Dp together;
The length error Dl or the phase error Dp of the at least one recording pattern in the length error Dl or the phase error Dp, or both the length error Dl and the phase error Dp are set as error target values other than 0. A recording / reproducing program for adjusting a shape of the recording signal with respect to a pattern.   The step of adjusting the shape of the recording signal includes a length error target value Dlt in which the length error Dl for each recording pattern is a target value for the length error or a phase error Dp for each recording pattern is a target value for the phase error. The shape of the recording signal for the recording pattern is set so that the phase error target value Dpt is equal to or the length error Dl is the length error target value Dlt and the phase error Dp is the phase error target value Dpt. The recording / reproducing program according to claim 11, wherein adjustment is performed.   The recording / reproducing program according to claim 12, wherein the length error target value Dlt of the at least one recording pattern is other than 0 and the phase error target value Dpt is 0.   The step of decoding is a maximum likelihood decoding step of maximum likelihood decoding of the digital signal, and reproduces information recorded in advance on the information recording medium in the form of a recording signal adjusted to minimize jitter, The calculated length error is Dlj and the phase error is Dpj, and the length error target value Dlt is 0 <Dlt <Dlj, or the phase error target value Dpt is 0 <Dpt <Dpj, The recording / reproducing program according to claim 12.   13. The recording / reproducing program according to claim 12, wherein the length error target value Dlt or the phase error target value Dpt differs depending on a difference in recording medium information recorded on the information recording medium. A recording signal adjusting device for adjusting the shape of a recording signal for recording information on an information recording medium based on information on the shape of the recording signal, a digital signal, and a decoding result of the digital signal,
Pattern detection means for generating a pulse signal for assigning the start and end edges of the recording signal for each recording pattern;
A displacement detection means for detecting a displacement from an ideal edge position at a start / end portion of a recording signal corresponding to the recording pattern by the digital signal, the decoding result, and the pulse signal;
Based on the positional deviation of the start and end portions of the recording signal, the length error Dl that is an error with respect to the length of the recording signal for each recording pattern or the phase error Dp that is an error with respect to the phase, or the length error Dl and the phase A recording information error calculating means for calculating the error Dp together;
The length error Dl or the phase error Dp of the at least one recording pattern in the length error Dl or the phase error Dp, or both the length error Dl and the phase error Dp are set as error target values other than 0. A recording signal adjusting apparatus for adjusting a shape of the recording signal with respect to a pattern.   The recording signal adjustment apparatus is configured such that a length error target value Dlt that is an error target value of a length error Dl for each recording pattern or a phase error target value Dpt that is an error target value of the phase error Dp is set to the length. Error target value storage means for storing both the error target value Dlt and the phase error target value Dpt is further provided, and the length error Dl for each recording pattern is the length error target value Dlt or the phase error Dp for each recording pattern. Is adjusted to the phase error target value Dpt, or the length error Dl is the length error target value Dlt and the phase error Dp is the phase error target value Dpt. The recording signal adjustment apparatus according to claim 16, wherein the recording signal adjustment apparatus is a recording signal adjustment apparatus.   18. The recording signal adjusting apparatus according to claim 17, wherein the length error target value Dlt of the at least one recording pattern is other than 0 and the phase error target value Dpt is 0.   The decoding result is a result of maximum likelihood decoding of the digital signal, and is calculated from a digital signal obtained by reproducing information recorded in advance on the information recording medium in the form of a recording signal adjusted to minimize jitter. The length error is Dlj and the phase error is Dpj, and the length error target value Dlt is 0 <Dlt <Dlj, or the phase error target value Dpt is 0 <Dpt <Dpj. The recording signal adjusting device according to claim 17.   18. The recording signal adjustment device according to claim 17, wherein the length error target value Dlt or the phase error target value Dpt varies depending on the recording medium information recorded on the information recording medium. A recording signal adjustment method for adjusting the shape of a recording signal for recording information on an information recording medium based on information on the shape of the recording signal, a digital signal, and a decoding result of the digital signal,
Generate a pulse signal to assign the start and end edges of the recording signal for each recording pattern,
Detecting a positional deviation from an ideal edge position at the start / end part of the recording signal according to the recording pattern by the digital signal, the decoding result, and the pulse signal,
Based on the positional deviation of the start and end portions of the recording signal, the length error Dl that is an error with respect to the length of the recording signal for each recording pattern or the phase error Dp that is an error with respect to the phase, or the length error Dl and the phase Calculate error Dp together,
The length error Dl or the phase error Dp of at least one recording pattern in the length error Dl or the phase error Dp, or both the length error Dl and the phase error Dp are set as error target values other than 0. A recording signal adjusting method, wherein the shape of the recording signal with respect to a pattern is adjusted.   In the recording signal adjusting method, the length error Dl for each recording pattern is a length error target value Dlt, which is a target value for the length error, or the phase error Dp for each recording pattern is a phase error target value. The shape of the recording signal with respect to the recording pattern is adjusted to the target value Dpt or so that the length error Dl becomes the length error target value Dlt and the phase error Dp becomes the phase error target value Dpt. The recording signal adjustment method according to claim 21, wherein the recording signal adjustment method is characterized in that:   The recording signal adjustment method according to claim 22, wherein the length error target value Dlt of the at least one recording pattern is other than 0 and the phase error target value Dpt is 0.   The decoding result is a result of maximum likelihood decoding of the digital signal, and is calculated from a digital signal obtained by reproducing information recorded in advance on the information recording medium in the form of a recording signal adjusted to minimize jitter. The length error is Dlj and the phase error is Dpj, and the length error target value Dlt is 0 <Dlt <Dlj, or the phase error target value Dpt is 0 <Dpt <Dpj. 23. A recording signal adjusting method according to 22.   23. The recording signal adjustment method according to claim 22, wherein the length error target value Dlt or the phase error target value Dpt varies depending on the recording medium information recorded on the information recording medium. Recording signal adjustment for causing a computer to execute adjustment processing for adjusting the shape of a recording signal for recording information on an information recording medium based on information on the shape of the recording signal, a digital signal, and a decoding result of the digital signal A program,
The recording signal adjustment program generates a pulse signal for assigning start and end edges of a recording signal for each recording pattern;
Detecting a positional deviation from an ideal edge position at a start / end portion of a recording signal corresponding to the recording pattern by the digital signal, the decoding result, and the pulse signal;
Based on the positional deviation of the start and end portions of the recording signal, the length error Dl that is an error with respect to the length of the recording signal for each recording pattern or the phase error Dp that is an error with respect to the phase, or the length error Dl and the phase Including calculating the error Dp together;
The length error Dl or the phase error Dp of the at least one recording pattern in the length error Dl or the phase error Dp, or both the length error Dl and the phase error Dp are set as error target values other than 0. A recording signal adjustment program for adjusting a shape of the recording signal with respect to a pattern.   The recording signal adjustment program includes a length error target value Dlt in which the length error Dl for each recording pattern is a target value for the length error or a phase error in which the phase error Dp for each recording pattern is a target value for the phase error. The shape of the recording signal with respect to the recording pattern is adjusted to the target value Dpt or so that the length error Dl becomes the length error target value Dlt and the phase error Dp becomes the phase error target value Dpt. 27. The recording signal adjustment program according to claim 26, wherein the recording signal adjustment program is a recording signal adjustment program.   28. The recording signal adjustment program according to claim 27, wherein the length error target value Dlt of the at least one recording pattern is other than 0 and the phase error target value Dpt is 0.   The decoding result is a result of maximum likelihood decoding of the digital signal, and is calculated from a digital signal obtained by reproducing information recorded in advance on the information recording medium in the form of a recording signal adjusted to minimize jitter. The length error is Dlj and the phase error is Dpj, and the length error target value Dlt is 0 <Dlt <Dlj, or the phase error target value Dpt is 0 <Dpt <Dpj. 27. The recording signal adjustment program according to 27. 28. The recording signal adjustment program according to claim 27, wherein the length error target value Dlt or the phase error target value Dpt is different depending on a difference in recording medium information recorded on the information recording medium.

Images