JPH02257474A - Discoid recording medium recording/reproducing device - Google Patents

Abstract

PURPOSE:To suppress a waveform interference from an adjacent track and to minimize a reproducing data error rate even when a track pitch is narrowed by performing two-dimensional waveform equalization in consideration of the interference from the adjacent track. CONSTITUTION:The subject device is provided with a waveform equalizing device consisting of an analog-digital (AD) converter 23 for sampling, quantizing and outputting an input signal from a discoid recording medium, memories 24 and 25 for storing a signal train as an output of the AD converter 23 by plural tracks and waveform equalizers 89, 90 and 138 for reading simultaneously signal trains of plural tracks from the memories 24 and 25 and performing waveform equalization against either of a waveform interference in the lengthwise direction of a track and the waveform interference from an adjacent track. By this method, the waveform interference from the adjacent track is suppressed, and the reproducing data error rate due to cross talk is minimized even when the track pitch is narrowed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a waveform equalization device for an optical disk device and an optical disk recording/reproducing device.

Conventional technology In recent years, optical disk devices that record and play back digital signals have been actively developed as large-capacity digital data storage devices. Based on the method and groove shape on the disk medium, there are two main types: continuous groove method and discrete groove method.
Block 5ervo Format (DBF)
The present invention relates to a waveform equalization device for an optical disk device and an optical disk recording/reproducing device using DBF. It is characterized by the stability of clock detection, and all timings are detected using clock pits written on the disk. The signal reproducing section of the device will be explained. The signal reproducing section of the conventional optical disc recording/reproducing apparatus as described above will be explained below with reference to the drawings. Fig. 12 shows a signal reproducing section of a conventional magneto-optical disk, and Figs. 13 and 14 are waveform diagrams for explaining its operation.a Fig. 15 shows a signal reproducing section of a conventional magneto-optical disk. Circuit diagram of waveform equalization circuit Part 1
In Figure 2, l is an optical head. The optical head is composed of a laser, a lens, an actuator, a polarizing beam splitter, a bin photodiode, a pre-pit signal reproducing circuit, a magneto-optical signal reproducing circuit, etc.; Track number 2 and 3 are peak hold section 4 is subtracter 5 is differential a6 is phase synchronization section 7 is Karan section 8 is switch 9 is waveform equalization section lO is address demodulation section 11 is system controller The mower 2 is a clock regenerator, the clock regenerator 72 is composed of a differentiator 5, a phase synchronization circuit 6, and a counter 7, 488 is a servo signal extractor, and the servo signal extractor 88 is a peak hold circuit 2. In Fig. 15, 12 is an AD conversion switch, 13 to 15 are D flip-flops (hereinafter abbreviated as D-FF), 16 to 18 are multiplication Ws, and 19 and 20 are adders. In FIG. 12, the optical head 1 outputs a focus error signal using a light spot formed on the optical disk 7o, and as shown in FIG.
Track 71 of the disk 70 in FIG.
Figure 13 shows the data format for recording and reproducing on a 3.5-inch magneto-optical disk.
As shown in (C), the data format for recording and reproducing a 3.5-inch magneto-optical disk is that one track per round is divided into 22 sectors, and one sector consists of 76 blocks, 1st O block to 2nd block of more 6 blocks. is a header block, and is an address indicating the sector number and track number. The 3rd block to the 75th block are data blocks, and one block consists of 2 servo bytes and 8 data bytes. As shown in FIG. 13(c), this servo byte is composed of a wobble mark for tracking error detection and a clock bit for clock reproduction. The phase-locked circuit 6 has a free-running frequency that is 110 times the repetition frequency of the clock pictogram signal, and receives the output of the differentiator 5 only near the reproduction timing of the clock bit according to the instruction signal of the counter 7. The output of the recovered clock is set to 110 by the counter 7.
The counter 7 is a 110 frequency counter as described above, and simultaneously divides the frequency of the reproduced clock output by 110 and simultaneously outputs the timing instruction signal of the clock bit and the wobble mark signal. Outputting a timing instruction signal a The clock regenerator 72 regenerates the clock through the operations described above. Peak hold 2.3 is the maximum value Vl of the wobble mark signal within the timing specified by the counter 7 as shown in FIG. 13(d).
, V2 is held and output, and subtracter 4 is peak hold 2.
．． The servo signal extractor 88 takes the difference between the outputs of 3 and outputs it as a tracking error signal.The servo signal extractor 88 outputs a tracking error signal by the above operation.A Here, the address signal and magneto-optical signal are recorded and reproduced using 4-11 modulation. , 4 4-1
In 1 modulation, 11 bits of data is allocated to 1 symbol of 1 byte length before modulation, and the rule is that the number of codes "l" after modulation is 4 within 11 bits of 1 symbol.
Therefore, even though 88 bits of data are recorded and reproduced for the 8 bytes of data within one block, this corresponds to 110 bits in terms of the length of one block. The write clock used for recording the magneto-optical signal is a reproduced clock reproduced from the clock bit, and similarly the data waveform etc. 41. Even if the reproduced clock is used for identification, the address signal and data signal output from the optical head l are connected to the switch 8. The circuit diagram of the waveform equalization circuit 9 is shown in FIG.
The converter 12 converts the analog address signal and magneto-optical signal into digital signals.The sampling signal is the regenerated clock of the phase synchronization circuit 7, and the clocks of the D-FFs 13 to 15 are also the regenerated clocks. The output of the circuit 12 is delayed by one cycle of the reproduced clock and outputted to the multipliers 16 to 18. The multipliers 16 to 18 multiply the delayed signal by coefficients W(-1) to W(1). and outputs to adder 19.20&D-FF13~1me FF
16~l& Adders 19 and 20 constitute a 3-tap transversal filter, and its transfer function H1 is H1=W(-1)4(n+1)+W(0)・X(n)+
W(-1)-X(n+1) Its characteristics are multiplier 1
The waveform equalization circuit 9 changes depending on coefficients 6 to 18.
The address demodulation circuit 10 detects the address signal from the output of the waveform equalization circuit 9 and determines the current address. The system controller 11 operates by taking in the output of the address demodulation circuit 10, and outputs a switching signal for switching between the address signal and the data signal to the switch 8.One of the characteristics of optical disks that the invention aims to solve is storage. Although it is said to have a large capacity, this is because the linear recording density is 20 Kbpi or more, which is equivalent to that of a magnetic disk device, and the inter-track pitch of the recording tracks is small, about 1.6 microns, so the areal recording density is large. However, even if this feature is further developed and there is a demand for even higher density, the method to achieve this is to increase the linear recording density, and the waveform interference caused by adjacent bits that occurs at this time is conventionally It is common to reduce this by using the waveform equalization circuit of the data reproducing section as shown in the example above. Another possibility is to reduce the track pitch and increase the areal recording density.
When the track pitch becomes 1 micron or less, crosstalk from adjacent tracks increases. However, in the waveform equalization circuit of the signal reproducing section of conventional magneto-optical disks, no consideration is given to this interference from adjacent tracks, resulting in negative effects. In view of the above problems, the present invention suppresses waveform interference from adjacent tracks, which was not considered at all in conventional one-dimensional waveform equalization circuits. The present invention provides fixed-dimensional and adaptive waveform equalization devices and disk-shaped recording medium recording/reproducing devices using the same.Means for solving the problems.To achieve the above objects. The recording/reproducing device includes an analog-to-digital converter that samples and quantizes an input signal from a disc-shaped recording medium, and outputs the quantized signal, a memory for storing a plurality of tracks of signal sequences output from the analog-to-digital converter, and the memory. The present invention has a waveform equalizer which simultaneously reads out the signal strings of multiple tracks from the track and equalizes the waveforms against both waveform interference in the longitudinal direction of the tracks and waveform interference from adjacent tracks. With the above configuration, it is possible to suppress waveform interference from adjacent tracks and reduce the reproduced data error rate due to crosstalk even when the track pitch is narrowed.Also, by making the waveform equalization device an adaptive waveform equalization device, it is possible to suppress waveform interference from adjacent tracks. Closely
Waveform interference fluctuations caused by recording power variations, optical spots, tracking errors, etc. are automatically compensated for and suppressed, and an adaptive waveform equalization device is automatically corrected and suppressed for clock timing errors and their fluctuations. Embodiment A waveform equalization device and an optical disk recording/reproducing device according to an embodiment of the present invention will be described below with reference to the drawings.
A first embodiment of the fixed type waveform equalization device of the present invention will be explained using the block diagram of FIG. 1 and the circuit diagram of the waveform equalization device of FIG. 4. In Figure 1, l is the optical head and the moa is 0.
2 and 3 are peak hold circuits 14 are subtracters; 5 is a differentiator; 6 is a phase synchronization circuit m7; 8 is a switch; 21 is a waveform equalization device 1O is an address demodulation circuit 22 system controller deya72
is a clock regenerator, and the clock regenerator 72 is composed of a differentiator 5, a phase synchronization circuit 6, and a counter 7.
is a servo signal extractor, and the servo signal extractor 88 is composed of a peak hold circuit 2.3 and a subtracter 4.The block diagram of the following embodiment is also similar. Similarly, the servo signal extractor 88 generates a regenerated clock from the clock bit as in the conventional example. Similarly, the servo signal extractor 88 outputs a tracking error signal from the maximum values Vl and V2 of the wobble mark signal as shown in FIG. 2(d). The address signal and data signal output from the optical head l are connected to the switch 8. The switch 8 also switches the address signal and data signal using the switching signal of the system controller 22. The waveform equalizer 21 is connected to the phase synchronization circuit 6. Output and system controller 22 RA
Waveform equalization is performed using the M READ/WRITE switching signal and the RAM address instruction signal. The address demodulation circuit 10 detects the address signal from the output of the waveform equalization device 21 and demodulates the current address.The system controller 22 operates by taking in the output of the address demodulation circuit 10, and switches between the address signal and the data signal. Output the signal to the switch 8 and send it to the waveform equalizer 21 in the RAM
A circuit diagram of a first embodiment of the fixed type waveform equalizer of the waveform equalizer 21 shown in FIG. 1 is shown in FIG. 4. In Figure 4, 23 is an AD converter, 24.25 is R
A Takeshi 26~30.40~44.55~59 is D-FF
, 31-35. 45-49. 60-64 are multipliers 36
~39.50~54.65~69 is an adder, a89 is a waveform equalizer, and waveform equalizer 89 is D-F F26~
30, multipliers 31 to 36, and adders 36 to 39 & 90 is a waveform equalizer, and the waveform equalizer 90 is D
-FFs 40 to 44, multipliers 45 to 49, and adders 50 to 5
138 is also a waveform equalizer,
D-FF55-59, multipliers 60-64, and adder 65-
In FIG. 4, the AD converter 23 converts the address signal and data signal of the analog signal output from the switch 8 into a digital signal by analog-to-digital conversion. Even if the output of the phase synchronization circuit 8 is used, the frequency of the reproduced clock signal is the same as the channel bit rate of the recorded and reproduced data, and even though the main power of the AD converter 23 is 8 bits, the output of the AD converter 23 is the RAM 24. 25
The capacity of each of RAM 24.25 is 1
RAM2 with capacity to record track data
4.25 uses the output of the phase synchronization circuit 8 as the clock (
＼R for RAM which is the output of the system controller 22
The EAD/WRITE switching signal switches to data reading and writing, and the RA of the system controller 22
The address of RAM 24.25 is switched by the M address instruction signal, and now the optimum waveform equalization of the m-th track is performed. When the RAM 24 outputs the data of the m-th track, the RAM 25 Since the output is one track later than the output of RAM24, the (m+1)th
At this time, the AD converter 23 outputs the data of the (o-1)th track.A The waveform equalizers 89, 90, and 138 are 5-tap transversal filters. The waveform equalizer 89 is
-1) Perform waveform equalization of the data of the th track. The waveform equalizer 90 performs waveform equalization on the m-th track and
,X.

Similarly, the waveform equalizer 138 performs waveform equalization on the (m+1)th track. The adder 54 adds the outputs of the waveform equalizer 89 and the waveform equalizer 90, and the adder 69 adds the outputs of the adder 54 and the waveform equalizer 138. This is an explanatory diagram of the dimensional arrangement.A In Fig. 3, the white circles represent clock bits, and the black circles indicate the position of the read clock.As shown in Fig. 3, there are 5 seeds per track.
,n)(m-i-1,i,i+1.n-j-1,j,
W(k, 1)(k-1, 0, 1, 1-2, -1,
..., 2.), the waveform equalizer output y(
Figure 2 is an explanatory diagram of the shape of the light spot.The central ellipse indicates the intensity distribution of the light spot.The large circle indicates the reading clock position, and the small circle indicates the As shown in Figure 2, the tap coefficient W(k, 1) of the waveform equalizer is determined according to the light spot shape, recording bit shape, etc.
In general, a light spot whose intensity distribution can be approximated by a Gaussian distribution is dominant in its characteristics. The coefficient matrix 1t(k, 1) is W(k, O) l > I W(k,
±1) l > l W(k, ±2) l k--1,
0,1 1W(0,1) I > l W(±l, l) l
l-2, -1,..., 2 indicate absolute values. By selecting the coefficient matrix W(k, 1) as described above, the waveform equalizer 89 and the waveform equalizer 138 are The waveform equalizer 90 operates to perform optimal waveform equalization of the data of the m-th track.With the configuration of the two-dimensional waveform equalizer described above, Optimized waveform equalization by suppressing waveform interference from adjacent tracks and waveform interference of adjacent codes Next, we will discuss a second embodiment of a fixed waveform equalizer in which the optical spot shape is symmetrical in the longitudinal and lateral directions of the track. FIG. 5 shows a circuit diagram of a second embodiment of the fixed waveform equalizer 21. In FIG. 5, 73-75, 80-82 are D-FFs, 76-78. 83-85 are multipliers 79.86
．． 87 is an adder & 139 is a waveform equalizer,
Waveform equalizer 139 (D-FF73 to 75. Multiplier 7
6 to 7 & adder 79, 140 is a waveform equalizer, and waveform equalizer 1401L D-FF80 to
82. Even if the waveform equalizers 139 and 140 are configured with 3-tap transversal filters, the intensity distribution of the light spot is In the symmetric case, the coefficient matrix W(k, 1) becomes W(k, 1)-11(
k)・12(1) (2),
The two-dimensional coefficient W(k, 1) is the longitudinal coefficient Wl(k)
It is possible to separate the waveform equalizer into the longitudinal direction and the transverse direction of the track, and the output of the waveform equalizer 21 y( The waveform equalizer 139 removes crosstalk from adjacent tracks, and the waveform equalizer 140 removes waveform interference due to adjacent bits in the lateral direction of the track. It works. With the above configuration, the characteristics of the intensity distribution of the light spot are symmetrical with respect to the longitudinal and lateral directions of the track.
Optical disk recording/reproduction using a fixed waveform equalizer with a simpler configuration and a fixed waveform equalizer that suppresses waveform interference from adjacent tracks and waveform interference from adjacent codes and performs optimal waveform equalization. In the above-described embodiment, the coefficients given to the multiplier are fixed. By adaptively changing the coefficients, more effective waveform equalization characteristics can be provided.

FIG. 2 shows an explanatory diagram of the shape of a light spot. For example, in a swing-arm supported optical system, the axis of the elliptical light spot intensity distribution shown in Figure 2 changes frequently depending on the position on the disk for recording and playback, that is, the address. The density changes depending on the address, and the coefficients of the waveform equalizer need to be changed frequently.To summarize the factors that cause variations in the two-dimensional recording and playback characteristics, the following figures are shown in Figure 6. As shown in the figure, the determining factors of waveform equalization characteristics are mainly the shape of the optical spot, which is related to the state during recording, the shape of the recording bit, which is caused by the fluctuation of the recording power, the lock timing, the focus, and the tracking, and the state during playback. Tracking can be divided into adjacent codes and code amount interference in the track direction due to fluctuations in sampling clock timing. Therefore, by giving an appropriate target signal, interference can be achieved by adaptively following these fluctuations. It is possible to make adaptive coefficients for suppressing the
,D,5tearns,'Adaptive Sign
al Processing, ' Prent 1c
e-Hatl, 1985) can be applied, but the target signal required here is to determine the code of the waveform-equalized output and, based on the result, determine the code amount according to the modulation method used. The decision should be made in consideration of the no-distortion condition of interference.The first embodiment of the adaptive waveform equalizer will be described below. Figure 7 shows the waveform of the first embodiment of the adaptive waveform equalizer. 9 is a circuit diagram of the equalizer, and FIG. 9 is a circuit diagram of the coefficient control circuit of the first embodiment of the adaptive waveform equalizer.
In the figure 91-95.105-109.120-12
4 is D-FF, 96-100.110-114.125
~129 are multipliers 101~104.115~119.
130 to 134 are adders 136 is combination barre 13
5.137 is a subtracter and 270 is a sign judger,
The sign determiner 270 includes a subtracter 135 and a comparator 136.
In FIG. 9, 195 to 239 are multipliers, 240 to 254 are D-FFs, and 255 to 26
9 is an adder. In FIG. 7, D-FF91 to 95
゜105~109.120~124, multiplier 96~10
0%110~114.125~129, adder 101~
104% 115 to 119. The basic waveform equalizer section composed of 130 to 134 is the same as in FIG. ) and Th to detect the sign of the original modulated signal and obtain a(m,n)(a(m,n)-
0, 1). In this case, if the adaptation of the waveform equalization characteristics is insufficient, there is a possibility that the judgment error will become large.
Although it is known that the waveform equalization characteristics eventually converge to near the optimal characteristics, although this affects the convergence characteristics of the adaptive algorithm, , n) and a on the distortion-free condition ζ of the code amount interference of the present invention. , J. RoDav
ey, 'Data Transmission”M
cGraw-Hill, 1965) in this case d(
m, n) - a(m, n)
(4) Therefore, using the sign determiner output a(m, n) as the target signal d(m, n), the error signal e(m, n
) - In other words, the subtracter 137 outputs the difference between the waveform equalizer output y (m, n) and the target signal a (m, n) as the error signal e (m, n). m, n) - d (m, n) - y (m, n) - a (m,
n)-y(m, n) (5) Coefficient control circuit 4 in Fig. 9
3×5 coefficient matrix W(k,
1) The coefficient control circuit shown in Figure 9 realizes the adaptive algorithm of the least square error method.
The coefficient matrix is updated according to the following formula so as to minimize the minimum error average of the error signal e(m, n) of the waveform equalizer shown in FIG. 7.
W., Thomas, 'The Two-Dimen.
sional Adaptive LMS (TDLMS)
) A1gorithm', IEEE Transa
tions on C1rcuits and Sy
stems, vol.

35, No, 5. May 1988. pp, 4
85-494) W (k, l)” + eyes - W (k, 1)
”'+2・μ・e(m, n) 4(m-i, n-j)
(
8) k-1, 0, 11-2, -1, 0..., 2 where μ
is the convergence coefficient (> 0) J(k, ri"' is the tap coefficient in the nth iteration calculation. In the circuit, the above formula is realized by D - F F for each coefficient, multiplier adder. However, in the actual circuit, ml(k, 1)'''
) is multiplied by α, but this is to improve the stability of the circuit, and the coefficient (2・μ) in the second term can be replaced by β. α≦11(2・μ)−β
(7) With the above configuration, it is possible to suppress waveform interference from adjacent tracks and reduce the reproduced data error rate due to crosstalk even when the track pitch is narrowed. It is possible to realize an adaptive waveform equalization device that automatically corrects and suppresses waveform interference fluctuations, and an optical disk recording/reproducing device using the adaptive waveform equalization device. A second embodiment that can improve the signal-to-noise ratio compared to the first embodiment will be described. FIG. 8 is a circuit diagram of a waveform equalizer of the second embodiment of the adaptive waveform equalization device. The figure is a circuit diagram of the coefficient control circuit of the second embodiment of the adaptive waveform equalizer.
．． 155-159.170-174.187-189 is D-FF, 146-150.160-164.175-
179.190. i91 is a multiplier 151-154.1
65-169.180-184, i92.193 is an addition 1 element 186 is a combo barre 185.194 is a subtracter 7. 271 is a sign determiner; sign determiner 271
is composed of a subtracter 185 and a comparator 186. The output is represented by a(m, n), and FIR low-pass filter 272 is an FIR low-pass filter.
18Q.

Consisting of multipliers 190 and 191 and adders 192 and 193, the output signal a (Ill, n) of the sign determiner 271
Bandwidth is limited. The coefficient of the multiplier 190, 1H is ε
(ε〉0) and a In this embodiment, in order to improve the signal-to-noise ratio, the interference condition in the track is relaxed and the sign determiner 27
1 output a8m, n) followed by Finite for band limitation.
By incorporating an Impulse Re5ponse low-pass filter (hereinafter abbreviated as FIR low-pass filter), the target signal d(m, n) is converted to d(m, n) = s ・a(m, n
-1)+a(m,n)+t: -a(m,n+1)(
8) However, it is set as ε〉0. With the above configuration, an adaptive waveform equalization device and an adaptive waveform etc., which have a uniform signal-to-noise ratio compared to the first embodiment of the adaptive waveform equalization device, etc. In the case of DBF, which is the control method for this optical disc, it is necessary to strictly control the playback clock timing error during recording and playback, and this (For example, in a magneto-optical disk device, where the clock pit reproducing circuit and the magneto-optical data section reproducing circuit are different, the delay time of each circuit may vary, or temperature changes may occur.) However, the adaptive waveform equalizer's adaptive tap coefficient matrix correction causes the delay characteristics to be approximated by the waveform equalizer depending on the recording and playback conditions. In the first and second embodiments of the adaptive waveform equalizer, the waveform equalizer operates in a linear manner at intervals of one cycle of the recovered clock. This delay correction effect is small; therefore, as a third embodiment of the adaptive waveform equalization device, by configuring a linear equalizer with an interval of 1/2 period of the recovered clock, this delay correction effect is small. Although it is possible to dramatically increase the correction effect (for example, literature: J, G, proakis,
"Digital Communications"
5th edition, McGraw-1
11, 1989) FIG. 10 shows a circuit diagram of the waveform equalizer of the third embodiment of the adaptive waveform equalization device.
a) and (b) show circuit diagrams of the coefficient control circuit of the third embodiment of the adaptive waveform equalizer.
282.300~30g, 327~335.356~3
60 is D-FF, 283~291.309~317
．． 336~344.361~364 are multipliers 292~
299.318~32B, 345~353.365~3
68 is an adder. The waveform equalizer has a 3x9 tap configuration to double the clock frequency. 355 is a converter. 354. 369 is a subtracter. 273 is a clock generation circuit. 507 is a sign determiner, and the sign determiner 507 is composed of a subtracter 354 and a comparator 355, and the output is expressed as a(m, n), 4 508
is an FIR low-pass filter, and the FIR low-pass filter 508 is composed of D-FF 356 to 36Q, multipliers 361 to 36, east adders 365 to 368, and sign determiner 507.
The band of the output signal a(m, n) is limited. The coefficients of multipliers 361 and 364 are η (η>0), and multiplier 3
The coefficient of 62.363 is ζ (ζ〉0) & FIR low-pass filter 508 is also configured with 5 taps to double the clock frequency.
-416 are multipliers 417-431 are adders 432-4
46 is a D-FF and 447 to 4 in Fig. 11(b)
482 is a multiplier 483 to 494 are adders 495 to 50
6 is a D-FF. Figure 11(a).

The coefficient control circuit in (b) is 3× of the waveform equalization circuit in FIG.
This circuit switches the 9-tap coefficient matrix W(k, 1). In FIG. 10, the clock generation circuit 273 generates a clock with twice the frequency from the recovered clock of the phase synchronization circuit 7. .25,
D-FF, also D-FF in Figure 15.16! Even if the signal of the clock generation circuit 273 is used as a sampling clock, the number of taps of the waveform equalizer is 9 to give the same effect as the waveform equalizer of the second adaptive waveform equalizer, and the waveform etc. The converter output y (m * n) is y (m, n) = W (k, 1) x (m-, n-1
) (9) However, -1, 0, 1, 1-4,
-3,...3.4 Also, Figure 15 (a), (b)
Each coefficient W(k, 1) of the coefficient control circuit is expressed by the following formula: W(k, 1)""■-W(k, 1)'" +2 ・p
・e(m, n)・X(m-i, n-j)
(10)k-1,0,11-
4, -3,..., 4, where μ is the convergence coefficient (>0) In the actual circuit, w(h, t)'' is multiplied by α, but this is to improve the stability of the circuit. , the coefficient (2・μ) of the second term can be replaced by β. α≦1, (2・μ)
μ)-β (11) Also, the target signal d(m, n) which is the output signal of the FIR low-pass filter 508 for band limitation of the sign determiner 507 is d(m, n)-
ζ fist a (m, n-2) + η・a (m, n-1) + a (m
, n)+η・a(m, n+1)+ζ・a(m, n+2
) + ζ -a (m, n + 2) where η, ζ > O (12) However, with the above configuration, it is possible to realize a linear equalizer with an interval of 1/2 period of the recovered clock. Optical disk recording using an adaptive waveform equalizer and an adaptive waveform equalizer that can automatically and efficiently correct clock timing errors and their fluctuations depending on the configuration.
Effects of the Invention The present invention suppresses waveform interference from adjacent tracks by performing two-dimensional waveform equalization in consideration of interference from adjacent tracks, and crosstalk even when the track pitch is narrowed. Although it is possible to reduce the reproduction data error rate due to linear recording density, it automatically corrects and suppresses waveform interference fluctuations due to recording power variations, optical spots, tracking errors, etc., but it also suppresses clock timing errors and their fluctuations. The purpose of the present invention is to provide a waveform equalization device that can automatically and efficiently correct this, and an optical disk recording/reproducing device using the same. It also provides a waveform equalization device that is easy to implement.

[Brief explanation of drawings]

FIG. 1 shows a block block diagram of a data reproducing section according to an embodiment of the present invention.
Figure 2 is an illustration of the shape of a light spot. Figure 3 is an illustration of a two-dimensional arrangement of sampling of reproduced signals. Figure 4 is a circuit diagram of the first embodiment of the fixed waveform equalizer of the present invention. is the circuit l of the second embodiment of the fixed waveform equalizer of the present invention.
FIG. 6 is an explanation of the fluctuation factors of waveform interference. FIG. 7 is a circuit diagram of the waveform equalizer of the first embodiment of the adaptive waveform equalization device of the present invention. FIG. 8 is the adaptive waveform etc. of the present invention. Figure 9 shows the circuit of the waveform equalizer of the second embodiment of the adaptive waveform equalizer of the present invention, and Figure 1θ shows the circuit of the coefficient control circuit of the first and 942nd embodiment of the adaptive waveform equalizer of the present invention. Circuit diagram of the waveform equalizer of the third embodiment of the adaptive waveform equalization device of FIGS.
) is the circuit of the coefficient control circuit of the third embodiment of the adaptive waveform equalizer of the present invention. FIG. 12 shows the blocks of the conventional example. FIG. 13 shows the recording/reproducing format. Operation explanation Figure 15 is a circuit diagram of a conventional waveform equalization circuit.Mut...Optical head, 2.3...Peak hold same section 4...Subtraction @ 5...Differential Image 6...Phase synchronization same area 7...Karan Hisashi 8.
...Switch, 9...Waveform equalization same section 10...
・Address demodulation circuit i 11.22...System controller, 12...AD conversion switch 13-15...
・D-FF, 16~18... Multiplier 19~20・
... Adder 21 ... Waveform equalizer [23 ... A
D converter 24.25...RA length 26-30.4
0~44.55~59.73~75.80~82.91
~95.105~109.120~124.240~2
54.141-145.155-159.170-17
4.187-189.274-282.300-308
ζ327~335.356~360.432~446.
495~506...D-FF, 31~35.45~
49.60-64.76-78.83-85.96-1
00%110~114.125~129.195~23
9.146~150.160~164.175~179
．． 190.1 old, 283-2 old, 309-317.33
6-344.361-364.370-416.447
~482... Multiplier 36~39.50~54.6
5~69.79.86.87.101~104.115
~119.130-134.255~269.151~
154.165-169.180-184.192.1
93.292-299.318-326.345-35
3.365~368.417~43L483~494・
... Adder 136.186.356 ... Combare Ku 135.137.185.194.354.38
9----Subtraction a 89.90.138.139.1
40...-Waveform equalizer 270.271,507...
...Sign determiner 272.508...Low pass filtering method 2
73... Name of clock generation transfer agent Patent attorney
Shigetaka Awano and 1 other person

Claims (7)

[Claims] (1) A recording and reproducing means for recording and reproducing information on a disc-shaped recording medium, a servo signal extractor for extracting a servo signal from a first input signal of the recording and reproducing means, and a servo signal extractor for extracting a servo signal from the first input signal of the recording and reproducing means. a clock regenerator for extracting a reproduction clock; a switch for switching between first and second input signals of the recording/reproducing means; and two-dimensional waveform equalization in the longitudinal and lateral directions of the track for the output signal of the switch. an address demodulation circuit that demodulates an address signal from the output of the waveform equalization device, and a control means that controls the switch and the waveform equalization device using the output of the address demodulation circuit. A disc-shaped recording medium recording/reproducing device. (2) an optical head that records and plays back information on an optical disk;
a servo signal extractor that extracts a servo signal from a first input signal of the optical head; a clock regenerator that extracts a reproduction clock from the first input signal of the optical head;
a switch for switching between the first and second input signals of the optical head; a waveform equalization device for performing two-dimensional waveform equalization in the longitudinal and transverse directions of the track on the output signal of the switch; and the waveform equalization device An optical disc recording/reproducing device comprising: an address demodulation circuit that demodulates an address signal from an output of the address demodulation circuit; and a control means that uses the output of the address demodulation circuit to control the switch and the waveform equalization device. (3) an analog-to-digital converter that samples and quantizes an input signal from a disc-shaped recording medium and outputs the same; a memory for storing a plurality of tracks of signal strings output from the analog-to-digital converter; A waveform equalizer comprising a waveform equalizer that simultaneously reads signal sequences of tracks and equalizes waveforms against both waveform interference in the longitudinal direction of the track and waveform interference from adjacent tracks. (4) an analog-to-digital converter that samples and quantizes an input signal from a disk-shaped recording medium and outputs the same; a memory for storing a plurality of tracks of signal strings output from the analog-to-digital converter; a waveform equalizer that simultaneously reads the signal strings of the tracks and equalizes the waveforms against both waveform interference in the longitudinal direction of the track and waveform interference from adjacent tracks; A waveform equalization device comprising: a sign determiner that detects a sign; and a coefficient control circuit that changes characteristics of the waveform equalizer so as to reduce an error between the output of the waveform equalizer and the output of the sign determiner. (5) an analog-to-digital converter that samples and quantizes an input signal from a disk-shaped recording medium and outputs the same; a memory for storing a plurality of tracks of signal sequences output from the analog-to-digital converter; a waveform equalizer that simultaneously reads the signal strings of the tracks and equalizes the waveforms against both waveform interference in the longitudinal direction of the track and waveform interference from adjacent tracks; a sign determiner for detecting a sign; an FIR low-pass filter for low-pass filtering and outputting the output of the sign determiner; and reducing an error between the output of the waveform equalizer and the output of the FIR low-pass filter. and a coefficient control circuit that changes the characteristics of the waveform equalizer. (6) The waveform equalization device according to claim (3), (4) or (5), wherein the sampling rate of the analog-to-digital converter is equal to the channel bit rate of the input signal. (7) The waveform equalization device according to claim (5), wherein the sampling rate of the analog-to-digital converter is equal to twice the channel bit rate of the input signal.