JP2000322842A - Recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable the max. likelihood decoding, without decoding errors, even if precoded signals are divided into blocks and specified characteristic patterns, etc., are inserted ahead or behind them. SOLUTION: The recorder comprises means for dividing recorded data A precoded adaptably to a disc-like recording medium into blocks N-1, N, N+1,,, of specified lengths, means for attaching specified characteristic patterns 0011 to the head and tail of each block, means for determining whether data values of each block are invertible, based on the relation between the last data value (1 in example) of the characteristic pattern 0011 nearest the head of each block and the final data value of a block just in front of each block, and means for inverting data values in the block determined to be inverted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device having a function of recording data on a recording medium such as a magneto-optical disk, and more particularly to a device for recording a recording signal on a disk-shaped recording medium having a divided recording area. The present invention relates to an apparatus having a function of dividing and recording.

[0002]

2. Description of the Related Art A magneto-optical recording / reproducing system can be regarded as a Gaussian low-pass filter when the whole is viewed as a baseband transmission line. Therefore, when the recording density is increased, intersymbol interference occurs between reproduced signals from adjacent recording areas, and the reproduced signal waveform is deteriorated. As a method for preventing intersymbol interference, a method is known in which an equalizer is inserted after the magneto-optical recording / reproducing system to correct the frequency characteristics of the entire transmission path to Nyquist characteristics. However, since the transmission band is limited in this method, it is difficult to apply it to recording / reproducing of a high-density magneto-optical disk.

Therefore, instead of eliminating intersymbol interference,
2. Description of the Related Art A signal transmission of a PR (partial response) method in which a signal is transmitted with intersymbol interference is employed for recording and reproduction of a high-density magneto-optical disk. FIG. 8 shows a conceptual diagram when the PR system is applied to a magneto-optical disk. In FIG. 8, a transmission system is configured by a precoder 701, an optical pickup 702, a magneto-optical disk 704 on which signals are recorded and reproduced using a magnetic head 703, and an equalizer 705. The precoder 701 eliminates error propagation when decoding a code transmitted by the PR method. Equalizer 705
In, the waveform equalization of the RF signal reproduced from the magneto-optical disk is performed, and intersymbol interference having a known correlation as a transmission system is generated.

[0004] The decoding algorithm of the multi-value discriminator 706 is as follows.
This is maximum likelihood decoding. That is, by utilizing the amplitude correlation of the PR system and referring to the state of the decoded signal before (or before or after) the identification time, a value that is statistically most probable is estimated as the state of the signal at the identification time. Is performed.

[0005]

In the signal transmission of the PR system, there are cases where it is desired to divide a signal after precoding into blocks of a predetermined number of bits and insert a unique pattern of a drive system before and after each block. . For example, there is a case where a disk has a clock component and data is recorded with the clock position removed. But if you do so,
The code correlation of the signal after precoding cannot be maintained at the division position. For this reason, a decoding error occurs in the maximum likelihood decoding using the correlation between the signals before and after the identification time.

The present invention has been made in view of such a problem, and the maximum likelihood decoding is performed even when a signal after precoding is divided into blocks and a unique pattern of a drive system is inserted before and after the divided blocks. An object is to be able to perform decoding without error.

[0007]

According to the first aspect of the present invention, there is provided a recording apparatus.
What is claimed is: 1. A recording device for recording a signal to be maximum-likelihood decoded during reproduction on a disk-shaped recording medium, comprising: An adding unit for adding a predetermined unique pattern before and / or after the block; and an adding unit that adds a specific pattern based on a relationship between a final data value of the unique pattern added immediately before each block and a final data value of the block immediately before each block. It is characterized by comprising determining means for determining whether or not the data value of the block can be inverted, and inverting means for inverting the data value in the block determined to be inverted by the determining means. According to a second aspect of the present invention, in the recording apparatus according to the first aspect, the dividing unit divides the recording data so that the recording data is divided and recorded in each of the recording areas divided and arranged on the disk-shaped recording medium. It is characterized by the following. According to a third aspect of the present invention, in the recording apparatus according to the first or second aspect, the precoding system is an NRZI system.

[0008]

Embodiments of the present invention will be described below with reference to examples.

FIG. 1 is a conceptual diagram showing an entire configuration of a drive system in an embodiment, FIG. 2 is a block diagram showing an example of a modulation unit 2 in FIG. 1, and FIG. FIG. 4 is a conceptual diagram showing a data area format, and FIG.
FIG. 5 is an explanatory diagram exemplifying an output A of the precoder 203, an output B of the data phase inverter 203, and an output C of the formatter 204 in FIG.

[0010] First, an error correction code is added to the user data input to the illustrated drive system by the error correction code unit 1. Next, the signal is digitally modulated by the modulation unit 2 and divided and rearranged so that the data can be recorded in a recording area divided and provided on the magneto-optical disk 3. The output of the modulator 2 is recorded on the magneto-optical disk 3 using the optical pickup 4 and the magnetic head 5. Marks having phase information for clock reproduction by the clock reproducing unit 8 are formed at predetermined intervals on the magneto-optical disk 3, and each area between the marks is a recording area. After the data recorded on the magneto-optical disk 3 is read out using the optical pickup 3, the demodulation unit 6 returns the data to the arrangement before the division rearrangement and performs digital demodulation. The demodulated data is error-corrected by the error correction decoding unit 7 and output to the outside.

The modulator 2 illustrated in FIG. 2 includes a digital modulator 201, a precoder 202, and a data phase inverter 20.
3. It has a determiner 207 and a formatter 204.

The digital modulator 201 performs data conversion for suppressing a DC component and restricting the shortest recording mark length and the longest recording mark length. In the precoder 202,
Data conversion for removing error propagation when decoding a code transmitted by the PR system, for example, NRZI conversion is performed. The conversion method in the precoder 202 forms a pair with the waveform equalization method in the waveform equalizer 602 of the demodulation unit 6.

In the data phase inverter 203, a data value of a portion (hereinafter, referred to as a “block”) corresponding to each block divided by the formatter 204 is inverted for each block in accordance with an instruction from the determiner 207. Or not inverted. The determiner 207 determines whether or not the data value in each block should be inverted, based on the final data value of the block immediately before each block and the final data value of the unique pattern added before and after each block by the formatter 204. , And the result is sent to the data phase inverter 203.

In the formatter 204, the output of the data phase inverter 203 corresponds to the above-mentioned recording area so that data can be divided and recorded in each recording area between marks provided on the magneto-optical disk 3 at predetermined intervals. The block is divided into blocks each having a predetermined length, and a unique pattern of the drive system is added before and after each block. In other words, FC is used as a portion corresponding to a mark formed in advance on the magneto-optical disk.
An M field is added, and a pre-write (Pre-write) field indicating the start of the block and a post-write (Post-write) field indicating the end of the block are added to each block.

Here, a method of determining inversion / non-inversion by the determiner 203 will be described with reference to FIG. In the figure, A
Is the output of the precoder 203 and B is the data phase inverter 20
The output of 3 and C is the output of the formatter 204.

The data output from the precoder 203 is divided by the formatter 204 into blocks of a predetermined length.
A unique pattern (fixed pattern “0011” in this example) is added before and after each block and recorded.
Due to the existence of the unique pattern, the relationship between the data values before and after the division position may be damaged at the time of reproduction, and as a result, the maximum likelihood decoding is hindered. For example, in the output signal A of the precoder 203, the last data value of the (N-1) block is "0", and the leading data value of the next N block is "1". Therefore, if a prewrite field “0011” is inserted before the N block, the original signal A has a relationship of “0 → 1” at the beginning of the N block, but the reproduced signal has a “0 → 1” relationship. 1 →
1], and a decoding error of maximum likelihood decoding occurs.

For this reason, the determiner 203 compares the final data value of the block immediately before each of the arbitrary blocks with the final data value of the unique pattern added to the head of the arbitrary block, and determines that the two match. If not, it inverts the data in the arbitrary block, and if they match, instructs the data phase inverter 203 not to invert the data in the arbitrary block. In response, the data phase inverter 203 inverts or does not invert the data in the arbitrary block. As a result, at the beginning of each block, the original signal A, which had a relationship of “0 → 1”, is read out as a “0 → 1” relationship in the reproduced signal. Naturally, in the original signal A, "0 →
0 "," 1 → 0 ", and" 1 → 1 ", the same applies to the reproduced signals" 0 → 0 "," 1 → 0 ".
The data is read out as "1 → 1".

The demodulation unit 6 illustrated in FIG. 4 has an A / D converter 601, an equalizer 602, a multi-value discrimination unit 603, an unformatter 604, and a digital demodulator 605.

In the A / D converter 601, the RF signal reproduced by the optical pickup 4 is digitized. In the equalizer 602, the digitized RF signal is equalized in waveform to desired characteristics. This waveform equalization method forms a pair with the data conversion method in the precoder 202 described above. For example, waveform equalization by the PR (1, 1) method or the PR (1, 2, 1) method is performed. The multi-level discrimination unit 603 performs maximum likelihood decoding for demodulating binary data according to the amplitude level. In the unformatter 604, the FCM field, the pre-write (Pre-write) field, and the post-write (Post-write) field are removed from each block, and the original data (signal A in FIG. 4) is reconstructed. .
The digital demodulator 605 performs the inverse conversion of the digital modulator 201 described above.

In the above description, it is generally stated that the data conversion in the digital modulator 201 is performed so that the DC component of the signal output from the precoder 202 is suppressed. As shown in FIG. 6, for example, as shown in FIG. 6, 16 types of signals are generated by scrambling the data after error correction using 16 types of scramble keys, and the DSV after precoding is generated from among them. This is done by selecting the signal that is minimal.

A description will be given with reference to FIG. Error correction code unit 1
The block data of the predetermined length described above is cut out from the data output from, and is input to 16 modulation units (modulation units 0 to 15), and is scrambled by using a different scramble key, for example, by a convolution method. You. Each signal scrambled by the scrambler 2001 is precoded by a precoder 2002, and a DSV calculator 2003 calculates a DSV. The peak value of the DSV in the block is stored in the peak holder 2004.

The determination unit 2005 compares the peak values stored in the peak holders 2004,..., 2004 of the 16 modulation units (modulation unit 0 to modulation unit 15) and finds the smallest one of them. The scramble key of the modulation unit having the peak value is determined by the scrambler 2008.
Give to. The determining unit 2005 also notifies the selecting unit 2006 of the modulation unit having the minimum peak value.
The selection unit 2006 selects the final DSV value of the modulation unit notified by the determination unit 2005 from among the block final DSV values output from the 16 modulation units (modulation unit 0 to modulation unit 15), and As an initial value of the DSV value for the block, D of each of the 16 modulation units is used.
SV computing units 2003, 2003.

The scrambler 2008 has a delay circuit 200
7 is scrambled using the scramble key provided from the determination unit 2005, and output to the precoder 202 together with the scramble key. The delay circuit 2007 uses 16 scramble keys provided from the determination unit 2005 to process the same block data as the block data output from the error correction code unit 1 and processed by the 16 modulation units. This is a circuit that delays by a time corresponding to the processing in the modulation unit. The processing after the precoder 202 is the same as that of the circuit shown in FIG.

After the DC component is suppressed using the circuit of FIG. 6, the data processed as described above after the precoder 202 and recorded on the magneto-optical disk 3 is reproduced by the circuit of FIG. The circuit of FIG.
The configuration up to the unformatter 604 is the same as the circuit of FIG. The circuit of FIG. 7 includes a descrambler 6 instead of the digital demodulator 605 after the unformatter 604.
06. The descrambler 606 generates a scramble key (FIG. 6) included in the unformatted signal.
(Descramble key added by the scrambler 2008). Thereby, the original data is reproduced.

The embodiment of the present invention has been described above.
It goes without saying that the present invention is not limited to such an embodiment. For example, in FIG. 6, the output of the delay circuit 2007 is scrambled using a scramble key that minimizes the peak value of DSV, but instead of this, the precoder 2002 of the modulation unit that minimizes the peak value of DSV is used. The output may be configured to be output to the data phase inverter 203. In FIG. 6, the peak values of the DSV of each signal scrambled using 16 types of scramble keys are compared. However, in order to simplify the circuit, the configuration is such that the final DSV of the block is compared. You may.

[0026]

According to the present invention, even when data after precoding is divided into blocks and recorded, read out, and subjected to waveform equalization for maximum likelihood decoding, a decoding error of maximum likelihood decoding is obtained at the leading end of each block. Can be prevented from increasing.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of the overall configuration of a drive system according to an embodiment.

FIG. 2 is a block diagram showing an example of a modulation unit 2 of FIG.

FIG. 3 is a conceptual diagram showing a format of a user data area on the magneto-optical disk 3 of FIG.

FIG. 4 is a block diagram showing an example of a demodulation unit 6 in FIG. 1;

FIG. 5 is an explanatory diagram illustrating an output A of a precoder 203, an output B of a data phase inverter 203, and an output C of a formatter 204 in FIG. 2;

FIG. 6 is a block diagram illustrating an example in which a modulation circuit that selects a signal having a minimum DC component from signals converted using a plurality of types of scramble keys is used as the digital modulator 201 in FIG. 2;

FIG. 7 is a block diagram of a circuit for demodulating a signal recorded using the modulation circuit of FIG. 6;

FIG. 8 is a conceptual diagram showing signal transmission of the PR system.

[Explanation of symbols]

 203 Data phase inverter 207 Decision unit

Claims (3)

[Claims] 1. A recording apparatus for recording a signal to be maximum-likely decoded during reproduction on a disk-shaped recording medium, wherein the pre-coded recording data is divided into blocks of a predetermined length so as to be adapted to the disk-shaped recording medium. Dividing means; adding means for adding a predetermined unique pattern before and / or after each block; and adding the last data value of the unique pattern added immediately before each block to the last data value of the block immediately before each block. Recording means for determining whether or not the data value of each block can be inverted based on the relationship; and inverting means for inverting the data value in the block determined to be inverted by the determining means. apparatus. 2. The method according to claim 1, wherein the dividing unit divides the recording data so that the recording data is divided and recorded in each of the recording areas divided and arranged on the disk-shaped recording medium. Recording device. 3. The recording apparatus according to claim 1, wherein the precoding method is an NRZI method.