JP2003223760A - Information reproducing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an information reproducing device that can make reproduction with less errors even when optimum recording is not made for the recording power or the like. <P>SOLUTION: A comparator 1 outputs a low level when an input signal S1 is higher than a first reference level, but outputs a high level gradually decreasing as the output time increases when the input signal is lower. The output is integrated in an integration circuit 2, and a difference is obtained between a second reference level and a DC component obtained by the integration in a subtraction circuit 3. This difference signal is changed to a second predetermined level -DC component. The comparator 1 is fed back with an input signal S1 AC-coupled with the reproduced signal when the calculated value of the reproduced signal shortest mark amplitude center level - longest mark amplitude center level - offset α1 (α1≥0) is 0 or larger, but when it is not 0 or larger, it is fed back with the input signal S1 AC-coupled, reproduced and reversed in polarity. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a CD-ROM drive, a CD for reproducing information by restoring an HF signal obtained by reading a digital signal recorded on a recording medium by magnetism or light to an original digital signal. -R /
The present invention relates to an information reproducing device such as an RW drive and a DVD drive.

[0002]

2. Description of the Related Art Conventionally, an information reproducing apparatus for an optical recording medium such as a CD or a DVD has used an auto slice circuit for judging original data from a reproduction signal of the recording medium. An example of a conventional auto slice circuit will be described below with reference to the drawings. FIG. 25 is a circuit diagram showing a configuration of a conventional auto slice circuit. This auto slice circuit includes a comparator 11, an integrating circuit 12, and a subtracting circuit 13, and an input signal which is a reproduced signal reproduced from a recording medium by the comparator 11. (HF signal) S11 is input, and its output signal is the comparator output signal S12.
Is input to the integrating circuit 12. The integrating circuit 12 performs integration processing on the comparator output signal S12 and outputs the integrated signal S1.
3 is output to the subtraction circuit 13. Then, the subtraction circuit 13 is configured to feed back the subtraction signal of the DC offset signal S14 and the integration signal S13 which is the output signal from the integration circuit 12 to the comparator 11 as the slice offset signal S15.

Next, the operation of the auto slice circuit shown in FIG. 1 will be described. FIG. 26 is a waveform diagram showing an output signal of each unit of the auto slice circuit shown in FIG. Initially, the slice offset signal S1 of the comparator 11
Assuming that 5 is 0 (V), when an arbitrary input signal (HF signal) S11 having a waveform as shown in (a) of FIG. 26 is input to the comparator 11, the comparator 11 outputs the input signal (H
F signal) S11 is compared with 0 (V), and the input signal is> 0
The comparator output signal S12 having a waveform as shown in FIG. 26B so that the output becomes 0 (V) when (V) and the output becomes +5 (V) when the input signal <0 (V).
Is output.

From the recording medium, a signal in which the voltage of the recording portion (mark portion) is lower than that of the unrecorded portion (space portion) is obtained, and the signal obtained by inverting the polarity of the signal is auto sliced. Assuming that the input signal (HF signal) S11 of the circuit is used, the slice offset signal S
In the determination based on the slice level when the voltage of 15 = 0 (V), the space length is smaller than the mark length. In that case, the comparator output signal S1 shown in FIG.
2 is averaged by the integrating circuit 12 to obtain an integrated signal S1.
As 3, the voltage V1 as shown in FIG. 26 (c) is obtained.

The integrated signal S13 having the voltage V1 is
The subtraction circuit 13 subtracts 1/2 of the high level voltage VR (assumed to be 5 (V) here) of the comparator output signal S12 from the DC offset signal S14 (generally, D
The C offset signal S14 is obtained by the low level voltage + (can be obtained by (high level voltage) − (low level voltage) / 2), and V0 as shown in (d) of FIG.
A slice offset signal S15 of = VR / 2-V1 is obtained. The slice offset signal S15 of V0 = VR / 2−V1 is fed back to the comparator 11, and the comparator 11 compares the input signal (HF signal) S11 with V0, and when the input signal> V0, the output becomes 0 (V). Becomes
When the input signal <V0, the comparator output signal S12 whose output becomes +5 (V) is output. By the feedback operation as described above, as shown in (e) of FIG. 26, the slice level considering V0 is set so that the space length = the mark length is always set, and the original data is reproduced from the reproduction signal of the recording medium. Can be judged.

On the other hand, in a recording apparatus for recording information on a recording medium such as an optical disk, trial writing is performed before recording an actual signal, and the signal quality of the trial writing portion is checked,
Generally, an operation called calibration is performed to obtain an optimum value of the intensity of laser light to be recorded. C
In a D-type or DVD-type recordable recording medium, an area for performing this trial writing is provided in the innermost circumference of the disk, and this area is used as a power calibration area (Power Calibrator).
Ion area (PCA), and the above series of operations is called Optimum Power Control (Optimum).
It is called Power Control (OPC).

As an example, OPC is performed as follows. First, the test signal is recorded on the PCA by changing the laser light intensity in several steps or continuously. Then, the recorded portion is reproduced, the position of the portion where the recording is optimally performed is obtained from the HF signal quality, and the laser light intensity at which the test signal is recorded at that position is set as the optimum value of the laser light intensity. The quality check of the reproduced HF signal is performed by detecting the symmetry (asymmetry) of the HF signal.

Specifically, the reproduced HF signal is cut with a high-pass filter for direct current components (this is referred to as "AC coupling"), and the top peak detection circuit and the bottom peak detection circuit use the HF signal for each recording power. Of the maximum value β1 (β1 is a positive value) on the + (plus) side and the maximum value β2 (β2 is a negative value) on the- (minus) side of
Β = (β1 + β2) / by the asymmetry arithmetic circuit
The asymmetry β for each recording power is calculated from (β1-β2). Then, from among the asymmetry β obtained,
The recording power that gives the asymmetry (generally β = 0) closest to the optimum asymmetry is selected, and this is determined as the optimum recording power. By performing actual recording using the determined optimum recording power, it is possible to perform recording with good reproduction signal quality.

[0009]

In the information reproducing apparatus having the above-mentioned conventional auto slice circuit, an appropriate slice level is automatically set according to the recording state. For example, whether the recording characteristics are good or bad is determined. The jitter, which is an index, shows a great change (deterioration) due to the change of the recording state due to the change of the recording strategy and the recording power. In particular, in the case of an optical recording medium having a thick recording layer, for example, in an optical recording medium having a recording layer made of an organic material, a recording strategy and a recording power setting range in which a jitter equal to or less than a specified value can be achieved are extremely narrow (margin is extremely small). There is a problem of (narrow). Therefore, it is very important to set the recording strategy and the recording power, and a very fine test recording (Optimum Power Control:
OPC) must be performed.

However, in reality, (1) the wavelength of the laser and its fluctuation range depend on each recording device,
The beam shapes, etc. are not the same (thus, even if the optimum recording strategy or recording power stored in advance is read by reading the media code, the optimum recording is not guaranteed) (2) Test recording area on the optical recording medium (3) If the recording strategy and recording power are set finely, the load on the recording device will increase and the cost will increase. (4) Even if the optimum recording conditions are set in the test recording, actual recording will be performed. At times, there is a possibility that detailed test recording before actual recording may be meaningless because of the fact that wavelength changes due to temperature and the recording position also changes.

That is, by performing OPC,
It is not always guaranteed that optimum recording is performed, and only favorable recording conditions are selected within the range selectable by the recording apparatus and at the time of executing the OPC. In particular, as the reproduction characteristic, the jitter is important, but the error rate is the most important. Because the jitter is an error rate expressed by another measurement method and given by the standard deviation of the difference between the theoretical value and the measured value, the existence of a small number of measured values that deviate greatly from the theoretical value is ignored. This is because the magnitude of the error rate greatly depends on the existence of a small number of measured values that are largely deviated from the theoretical value, so that the error rate needs to be more important than the jitter. As described above, in the conventional information reproducing apparatus, there is a problem that the recording portion which is not recorded on the recording medium under the optimum recording condition cannot be read out with good characteristics.

The present invention has been made to solve the above problems, and provides an information reproducing apparatus capable of reproducing with a low error rate even when the recording apparatus does not select an optimum recording condition such as recording power. It is an object of the present invention to realize the above and reduce the load and cost of the recording apparatus.

[0013]

In order to achieve the above object, the present invention provides the following information reproducing apparatus (1) to (16). (1) In an information reproducing apparatus that records original mark information and reproduces the original information by discriminating the original information from the reproduced signal of the recording medium such that the output signal is lower in the recorded portion than in the unrecorded portion, the input signal A is the first If it is higher than the predetermined level value B, a low level signal is output, and if it is lower than the first predetermined level value B, a high level signal is output such that the level value decreases as the output time increases. Comparing means,
It has an integrating means for integrating the output signal outputted by the comparing means, and obtains a difference signal E between the second predetermined level value C and the DC component value D obtained by the integration processing by the integrating means, The auto slicing means is configured to feed back the difference signal E to the comparator means, and the auto slicing means feeds the difference signal E returned to the comparator means (the second predetermined level value C) −
(DC component value D), and the calculated value F of (shortest mark amplitude center level value)-(longest mark amplitude center level value) -offset value α1 (where α1 ≧ 0) is 0 or more (F ≧ In the case of 0), a signal obtained by AC-coupling the reproduction signal is selected as the input signal A. When the calculated value is not 0 or more (F ≦ 0), reproduction is performed by AC-coupling the reproduction signal and inverting the polarity. An information reproducing apparatus in which an inverted signal is selected as the input signal A and is switched and input.

(2) In the information reproducing apparatus for recording the mark length and discriminating the original information from the reproduced signal of the recording medium such that the output signal is lower than that of the unrecorded portion, the input signal A Is higher than the first predetermined level value B, a low level signal is output when it is lower than the first predetermined level value B, and a high level signal whose level value is decreased as the output time is increased. It has a comparator means for outputting each and an integrating means for integrating the output signal output by the comparator means, and a second predetermined level value C and a DC component value D obtained by the integration processing by the integrating means. Of the difference signal E, and the difference signal E is fed back to the comparator means, and the auto slice means returns to the comparator means. The difference signal E is set to (the second predetermined level value C) − (the direct current component value D), and {(plus side amplitude maximum level value) + (minus side amplitude) in the signal obtained by AC coupling the reproduction signal. Maximum level value)} /
{(Plus amplitude maximum level value)-(minus amplitude maximum level value)} + offset value α2 (where α2 ≧
0) when the calculated value G is 0 or less (G ≦ 0), a signal obtained by AC coupling the reproduction signal is selected as the input signal A, and when the calculated value is not 0 or less (G ≧ 0), the above An information reproducing apparatus in which a reproduction inversion signal in which the reproduction signal is AC-coupled and its polarity is inverted is selected as the input signal A and is switched and input.

(3) In the information reproducing apparatus for reproducing the original information by discriminating the original information from the reproduced signal of the recording medium in which the mark length is recorded and the output signal is lower than that of the unrecorded portion, the input signal A Is higher than the first predetermined level value B, a low level signal is output when is lower than the first predetermined level value B, and a high level signal whose level value is decreased as the output time is increased. It has a comparator means for outputting each and an integrating means for integrating the output signal output by the comparator means, and a second predetermined level value C and a DC component value D obtained by the integration processing by the integrating means. Of the difference signal E, and the difference signal E is fed back to the comparator means, which auto-slice means returns to the comparator means. The difference signal E is set to (the second predetermined level value C)-(the DC component value D), and the shortest mark {(plus side maximum amplitude level value) + (minus in the signal obtained by AC coupling the reproduction signal) Side amplitude maximum level value)} / {(plus side amplitude maximum level value)-(minus side amplitude maximum level value)} calculated value H is 0 or more (H
In the case of ≧ 0), a signal obtained by AC-coupling the reproduction signal is selected as the input signal A. When the calculated value is not 0 or more (H ≦ 0), the reproduction signal is AC-coupled to invert the polarity. An information reproducing apparatus in which a reproduction inversion signal is selected as the input signal A and is switched and input.

(4) In the information reproducing apparatus for reproducing the original information by discriminating the original information from the reproduced signal of the recording medium in which the mark length is recorded and the output signal is lower than the unrecorded portion, the input signal A Is higher than the first predetermined level value B, a low level signal is output when it is lower than the first predetermined level value B, and a high level signal whose level value is decreased as the output time is increased. It has a comparator means for outputting each and an integrating means for integrating the output signal output by the comparator means, and a second predetermined level value C and a DC component value D obtained by the integration processing by the integrating means. Of the difference signal E, and the difference signal E is fed back to the comparator means, and the auto slice means returns to the comparator means. The difference signal E is set to (the second predetermined level value C)-(the DC component value D), and the reproduction signal is AC-coupled to maintain its polarity, and the reproduction signal is AC-coupled to change the polarity. Information in which one of the inverted signal and (the second predetermined level value C)-(the direct current component value D) which is 0 or more is selected and input as the input signal A. Playback device.

(5) In the information reproducing apparatus for recording the mark length and discriminating the original information from the reproduced signal of the recording medium such that the output signal increases with respect to the unrecorded portion, the input signal A Is higher than the first predetermined level value B, a low level signal is output when it is lower than the first predetermined level value B, and a high level signal whose level value is decreased as the output time is increased. It has a comparator means for outputting each and an integrating means for integrating the output signal output by the comparator means, and a second predetermined level value C and a DC component value D obtained by the integration processing by the integrating means. Of the difference signal E, and the difference signal E is fed back to the comparator means, and the auto slice means returns to the comparator means. The difference signal E is set to (the second predetermined level value C) − (the DC component value D), and the (shortest mark amplitude center level value) − (longest mark amplitude center level value) + offset value α1 in the reproduction signal. (However, α1 ≧
When the calculated value F of 0) is 0 or less (F ≦ 0), the reproduced inverted signal in which the reproduced signal is AC-coupled and the polarity is inverted is selected as the input signal A, and the calculated value is not 0 or less ( In the case of F ≧ 0), an information reproducing apparatus adapted to select a signal obtained by AC-coupling the reproduced signal as the input signal A and switch and input the signal.

(6) In the information reproducing apparatus for reproducing the original information by discriminating the original information from the reproduced signal of the recording medium in which the mark length is recorded and the output signal is increased with respect to the unrecorded portion, the input signal A Is higher than the first predetermined level value B, a low level signal is output when is lower than the first predetermined level value B, and a high level signal whose level value is decreased as the output time is increased. It has a comparator means for outputting each and an integrating means for integrating the output signal output by the comparator means, and a second predetermined level value C and a DC component value D obtained by the integration processing by the integrating means. Of the difference signal E, and the difference signal E is fed back to the comparator means, which auto-slice means returns to the comparator means. The difference signal E is set to (the second predetermined level value C) − (the direct current component value D), and {(plus side amplitude maximum level value) + (minus side amplitude) in the signal obtained by AC coupling the reproduction signal. Maximum level value)} /
{(Plus side maximum amplitude level value)-(minus side maximum amplitude level value)}-offset value α2 (where α2 ≧
When the calculated value G of 0) is 0 or more (G ≧ 0), the reproduction inversion signal in which the reproduction signal is AC-coupled and the polarity is inverted is selected as the input signal A, and the calculation value is not 0 or more ( In the case of G ≦ 0), an information reproducing apparatus adapted to select a signal obtained by AC-coupling the reproduced signal as the input signal A and switch and input the signal.

(7) In the information reproducing apparatus for recording the mark length and discriminating the original information from the reproduced signal of the recording medium such that the output signal increases with respect to the unrecorded portion, the input signal A Is higher than the first predetermined level value B, a low level signal is output when is lower than the first predetermined level value B, and a high level signal whose level value is decreased as the output time is increased. It has a comparator means for outputting each and an integrating means for integrating the output signal output by the comparator means, and a second predetermined level value C and a DC component value D obtained by the integration processing by the integrating means. Of the difference signal E, and the difference signal E is fed back to the comparator means, which auto-slice means returns to the comparator means. The difference signal E is set to (the second predetermined level value C)-(the DC component value D), and the shortest mark {(plus side maximum amplitude level value) + (minus in the signal obtained by AC coupling the reproduction signal) Side maximum amplitude level value)} / {(plus side maximum amplitude level value)-(minus side maximum amplitude level value)} calculated value H is 0 or less (H
≤0), the reproduction signal is AC-coupled and the polarity is inverted, and the reproduction inversion signal is selected as the input signal A. When the calculated value is not 0 or less (H≥0), the reproduction signal is AC. An information reproducing apparatus in which a combined signal is selected as the input signal A and switched and input.

(8) In the information reproducing apparatus for recording the mark length and discriminating the original information from the reproduced signal of the recording medium such that the output signal increases with respect to the unrecorded portion, the input signal A Is higher than the first predetermined level value B, a low level signal is output when it is lower than the first predetermined level value B, and a high level signal whose level value is decreased as the output time is increased. It has a comparator means for outputting each and an integrating means for integrating the output signal output by the comparator means, and a second predetermined level value C and a DC component value D obtained by the integration processing by the integrating means. Of the difference signal E, and the difference signal E is fed back to the comparator means, which auto-slice means returns to the comparator means. The difference signal E is set to (the second predetermined level value C)-(the DC component value D), and the reproduction signal is AC-coupled to maintain its polarity, and the reproduction signal is AC-coupled to change the polarity. Information in which one of the inverted signal and (the second predetermined level value C)-(the direct current component value D) which is 0 or more is selected and input as the input signal A. Playback device.

(9) In the information reproducing apparatus which reproduces the original information by discriminating the original information from the reproduced signal of the recording medium in which the mark length is recorded and the output signal is lower than the unrecorded portion, the input signal A Is lower than the first predetermined level value B, a low level signal is output when is higher than the first predetermined level value B, and a high level signal is output when the level value is decreased as the output time increases. It has a comparator means for outputting each and an integrating means for integrating the output signal output by the comparator means, and a second predetermined level value C and a DC component value D obtained by the integration processing by the integrating means. Of the difference signal E, and the difference signal E is fed back to the comparator means, which auto-slice means returns to the comparator means. The difference signal E is set to (the DC component value D)-(the second predetermined level value C), and the (shortest mark amplitude center level value)-(longest mark amplitude center level value) -offset value α1 in the reproduction signal. (However, α1
When the calculated value F of ≧ 0) is 0 or more (F ≧ 0), the reproduction inversion signal obtained by AC coupling the reproduction signal and inverting the polarity is selected as the input signal A, and the calculation value is not 0 or more. In the case of (F ≦ 0), an information reproducing apparatus adapted to select a signal obtained by AC-coupling the reproduced signal as the input signal A and switch and input the signal.

(10) In the information reproducing apparatus which reproduces the original information by discriminating the original information from the reproduced signal of the recording medium in which the mark length is recorded and the output signal is lower than the unrecorded portion, the input signal A Is lower than the first predetermined level value B, a low level signal is output when is higher than the first predetermined level value B, and a high level signal is output when the level value is decreased as the output time increases. It has a comparator means for outputting each and an integrating means for integrating the output signal output by the comparator means, and a second predetermined level value C and a DC component value D obtained by the integration processing by the integrating means. Of the differential signal E, and the differential signal E is fed back to the comparator means, and the automatic slice means is provided to the comparator means. The difference signal E to be returned is set to (the DC component value D)-(the second predetermined level value C), and {(plus side amplitude maximum level value) + (minus side of the reproduced signal is AC-coupled. Maximum amplitude level)} /
{(Plus amplitude maximum level value)-(minus amplitude maximum level value)} + offset value α2 (where α2 ≧
When the calculated value G of 0) is 0 or less (G ≦ 0), a reproduction inversion signal obtained by AC coupling the reproduction signal and inverting the polarity is selected as the input signal A, and the calculated value is not 0 or less ( In the case of G ≧ 0), the information reproducing apparatus is configured such that a signal obtained by AC-coupling the reproduction signal is selected as the input signal A and is switched and input.

(11) In the information reproducing apparatus for reproducing the original information by discriminating the original information from the reproduced signal of the recording medium in which the mark length is recorded and the output signal is lower than the unrecorded portion, the input signal A Is lower than the first predetermined level value B, a low level signal is output when the output level is higher than the first predetermined level value B, and a high level signal is output when the output time is increased. It has a comparator means for outputting each and an integrating means for integrating the output signal output by the comparator means, and a second predetermined level value C and a DC component value D obtained by the integration processing by the integrating means. Of the differential signal E, and the differential signal E is fed back to the comparator means, and the automatic slice means is provided to the comparator means. The difference signal E to be returned is set to (the DC component value D)-(the second predetermined level value C), and the shortest mark {(plus side maximum amplitude level value) + ( If the calculated value H such that the minus maximum amplitude level value)} / {(plus side maximum amplitude level)-(minus side maximum amplitude level)} is 0 or more (H ≧ 0), the above reproduction signal is set. Select the reproduction inversion signal AC-coupled and inverted in polarity as the input signal A,
An information reproducing apparatus in which, when the calculated value is not 0 or more (H ≦ 0), a signal obtained by AC-coupling the reproduced signal is selected as the input signal A and is switched and input.

(12) In the information reproducing apparatus for recording the mark length and discriminating the original information from the reproduced signal of the recording medium such that the output signal is lower than that of the unrecorded portion, the input signal A Is lower than the first predetermined level value B, a low level signal is output when the output level is higher than the first predetermined level value B, and a high level signal is output when the output time is increased. It has a comparator means for outputting each and an integrating means for integrating the output signal output by the comparator means, and a second predetermined level value C and a DC component value D obtained by the integration processing by the integrating means. Of the differential signal E, and the differential signal E is fed back to the comparator means, and the automatic slice means is provided to the comparator means. The difference signal E to be returned is set to (the DC component value D)-(the second predetermined level value C), and the reproduction signal is AC-coupled so as not to change the polarity, and the reproduction signal is AC-coupled and the polarity is changed. Of either of the signals obtained by inverting the above, the one in which (the above-mentioned DC component value D)-(the above-mentioned second predetermined level value C) becomes 0 or less is selected and inputted as the above-mentioned input signal A. Information reproduction device.

(13) In the information reproducing apparatus for reproducing the original information by discriminating the original information from the reproduced signal of the recording medium in which the mark length is recorded and the output signal is increased with respect to the unrecorded portion, the input signal A Is lower than the first predetermined level value B, a low level signal is output when is higher than the first predetermined level value B, and a high level signal is output when the level value is decreased as the output time increases. It has a comparator means for outputting each and an integrating means for integrating the output signal output by the comparator means, and a second predetermined level value C and a DC component value D obtained by the integration processing by the integrating means. Of the differential signal E, and the differential signal E is fed back to the comparator means, and the automatic slice means is provided to the comparator means. The difference signal E to be returned is set to (the DC component value D)-(the second predetermined level value C), and the (shortest mark amplitude center level value)-(longest mark amplitude center level value) + offset value in the reproduction signal. α1 (however, α1
When the calculated value F of ≧ 0) is 0 or less (F ≦ 0), a signal obtained by AC coupling the reproduction signal is selected as the input signal A. When the calculated value is not 0 or less (F ≧ 0), An information reproducing apparatus in which a reproduction inversion signal in which the reproduction signal is AC-coupled and the polarity of which is inverted is selected as the input signal A and is switched and input.

(14) In the information reproducing apparatus for reproducing the original information by discriminating the original information from the reproduced signal of the recording medium in which the mark length is recorded and the output signal is increased with respect to the unrecorded portion, the input signal A Is lower than the first predetermined level value B, a low level signal is output when the output level is higher than the first predetermined level value B, and a high level signal is output when the output time is increased. It has a comparator means for outputting each and an integrating means for integrating the output signal output by the comparator means, and a second predetermined level value C and a DC component value D obtained by the integration processing by the integrating means. The auto slicing means configured to obtain the difference signal E of the above and feed back the difference signal E to the comparing means. The difference signal E to be returned is set to (the DC component value D)-(the second predetermined level value C), and {(plus side amplitude maximum level value) + (minus side of the reproduced signal is AC-coupled. Maximum amplitude level)} /
{(Plus side maximum amplitude level value)-(minus side maximum amplitude level value)}-offset value α2 (where α2 ≧
When the calculated value G of 0) is 0 or more (G ≧ 0), a signal obtained by AC coupling the reproduction signal is selected as the input signal A, and when it is not 0 or more (G ≦ 0), the reproduction signal is AC.
The reproduction inversion signal in which the polarity is combined and the polarity is inverted is used as the input signal A.
An information reproducing apparatus which is selected as and is switched and input.

(15) In the information reproducing apparatus for recording the mark length and reproducing the original information by discriminating the original information from the reproduced signal of the recording medium such that the output signal increases with respect to the unrecorded portion, the input signal A Is lower than the first predetermined level value B, a low level signal is output when is higher than the first predetermined level value B, and a high level signal is output when the level value is decreased as the output time increases. It has a comparator means for outputting each and an integrating means for integrating the output signal output by the comparator means, and a second predetermined level value C and a DC component value D obtained by the integration processing by the integrating means. Of the differential signal E, and the differential signal E is fed back to the comparator means, and the automatic slice means is provided to the comparator means. The difference signal E to be returned is set to (the DC component value D) − (the second predetermined level value C), and the shortest mark {(plus side maximum amplitude level value) + ( If the calculated value H such that the negative maximum amplitude level value)} / {(the positive maximum amplitude value)-(the negative maximum amplitude value)} is 0 or less (H ≦ 0), the reproduction signal is An AC-coupled signal is selected as the input signal A, and when the calculated value is not 0 or less (H ≧ 0), a reproduction inversion signal obtained by AC-coupling the reproduction signal and inverting the polarity is selected as the input signal A. Then, the information reproducing apparatus is adapted to switch and input respectively.

(16) In the information reproducing apparatus for reproducing the original information by discriminating the original information from the reproduced signal of the recording medium in which the mark length is recorded and the output signal is increased with respect to the unrecorded portion, the input signal A Is lower than the first predetermined level value B, a low level signal is output when is higher than the first predetermined level value B, and a high level signal is output when the level value is decreased as the output time increases. It has a comparator means for outputting each and an integrating means for integrating the output signal output by the comparator means, and a second predetermined level value C and a DC component value D obtained by the integration processing by the integrating means. Of the differential signal E, and the differential signal E is fed back to the comparator means. The difference signal E to be returned is set to (the DC component value D)-(the second predetermined level value C), and the reproduction signal is AC-coupled so as not to change the polarity, and the reproduction signal is AC-coupled to the polarity. One of the inverted signal and the (DC component value D) − (second predetermined level value C) which becomes 0 or less is selected and input as the input signal A. Information reproducing device.

In the information reproducing apparatus of the above (1), when the mark length is recorded and the recording portion discriminates the original information from the reproduction signal of the recording medium in which the output signal is lower than that of the unrecorded portion, reproduction is performed. , If the input signal A is lower than the first predetermined level value B, a low level signal is output. Conversely, if the input signal A is lower than the first predetermined level value B, the level value is increased as the output time increases. Output a high level signal, and integrate the output signal to obtain the difference between the second predetermined level value C and the DC component value D obtained by the integration, and obtain the difference signal E Is fed back to the comparator means, the difference signal E is taken as C-D, and ((shortest mark amplitude center level value)-(longest mark amplitude center level value))-in the reproduction signal of the recording medium on which the mark length is recorded. Calculation of α1 (where α1 ≧ 0) When the value F is F ≧ 0, the AC-coupled reproduction signal from the recording medium on which the mark length is recorded is selected as the input signal A, and when F ≦ 0, the AC from the recording medium on which the mark length is recorded is selected. A reproduction inversion signal obtained by inverting the polarity of the combined reproduction signal is selected as the input signal A and is switched and input.

In the information reproducing apparatus of the above (2), when the mark length is recorded and the recording portion discriminates the original information from the reproduction signal of the recording medium such that the output signal is lower than that of the unrecorded portion, the information is reproduced. , If the input signal A is higher than the first predetermined level value B, the low level signal is output. Conversely, if the input signal A is lower than the first predetermined level value B, the level value is decreased with the increase of the output time. Such a high level signal is output, the output signal is integrated, the difference between the second predetermined level value C and the DC component value D obtained by the above integration is obtained, and the difference signal E is fed back to the comparator means. The difference signal E is C-D
In the signal obtained by AC coupling the reproduction signal of the recording medium on which the mark length is recorded, {(the maximum amplitude level value on the plus side)
+ (Minus-side amplitude maximum level value)} / {(plus-side amplitude maximum level value)-(minus-side amplitude maximum level value)} + α2 (however, α2 ≧ 0), the calculated value G is G ≦ 0
In the case of, the AC-coupled reproduction signal from the recording medium in which the mark length is recorded is selected as the input signal A, and in the case of G ≧ 0, the AC-coupled reproduction signal from the recording medium in which the mark length is recorded is selected. Playback inversion signal with inverted polarity is input signal A
Select as and switch input.

In the information reproducing apparatus of the above (3), when the mark length is recorded and the recording portion discriminates the original information from the reproduction signal of the recording medium such that the output signal is lower than that of the unrecorded portion, the information is reproduced. , A low level signal when the input signal A is higher than the first predetermined level value B, and a high level which decreases when the input signal is lower than the predetermined level value B as the output time increases. A signal is output, the output signal is integrated, the difference between the second predetermined level value C and the DC component value D obtained by the above integration is obtained, and when the difference signal E is fed back to the comparator means, The difference signal E is C-D, and the reproduction signal of the recording medium on which the mark length is recorded is AC-coupled and the shortest mark {(plus side amplitude maximum level value) + (minus side amplitude maximum level value)} / {(Plus maximum amplitude level Value) − (maximum amplitude level value on the minus side)} when H ≧ 0, the AC-coupled reproduction signal from the recording medium on which the mark length is recorded is selected as the input signal A, and H ≦ In the case of 0, a reproduction inversion signal obtained by inverting the polarity of the AC-coupled reproduction signal from the recording medium on which the mark length is recorded is selected as the input signal A, and is switched and input.

In the information reproducing apparatus of the above (4), when the mark length is recorded and the recording portion discriminates the original information from the reproduction signal of the recording medium such that the output signal is lower than that of the unrecorded portion, the information is reproduced. , If the input signal A is higher than the first predetermined level value B, the low level signal is output. Conversely, if the input signal A is lower than the first predetermined level value B, the level value is decreased with the increase of the output time. Such a high level signal is output, the output signal is integrated, the difference between the second predetermined level value C and the DC component value D obtained by the above integration is obtained, and the difference signal E is fed back to the comparator means. In this case, the difference signal E is set to CD, and the AC-coupled reproduction signal from the recording medium on which the mark length is recorded is set as the input signal A without changing the polarity, and the polarity is inverted to the input signal A. , And the slice offset signal Selectively inputting ≧ 0 and becomes better as the input signal A.

In the information reproducing apparatus of the above (5), when the mark length is recorded and the recording portion discriminates the original information from the reproduction signal of the recording medium such that the output signal increases with respect to the unrecorded portion, the information is reproduced. , If the input signal A is higher than the first predetermined level value B, the low level signal is output. Conversely, if the input signal A is lower than the first predetermined level value B, the level value is decreased with the increase of the output time. Such a high level signal is output, the output signal is integrated, the difference between the second predetermined level value C and the DC component value D obtained by the above integration is obtained, and the difference signal E is fed back to the comparator means. At that time, the difference signal E is set to CD, and (shortest mark amplitude center level value)-(longest mark amplitude center level value) + α1 (where α1 ≧ 0) in the reproduction signal of the recording medium on which the mark length is recorded. If the calculated value F is F ≦ 0, A from the recording medium recorded
A reproduction inversion signal obtained by inverting the polarity of the C-coupled reproduction signal is selected as the input signal A, and when F ≧ 0, an AC-coupled reproduction signal from the recording medium on which the mark length is recorded is selected as the input signal A. Then switch input.

In the information reproducing apparatus of the above (6), when the mark length is recorded and the recording portion discriminates the original information from the reproduction signal of the recording medium such that the output signal increases with respect to the unrecorded portion, the information is reproduced. , If the input signal A is higher than the first predetermined level value B, the low level signal is output. Conversely, if the input signal A is lower than the first predetermined level value B, the level value is decreased with the increase of the output time. Such a high level signal is output, the output signal is integrated, the difference between the second predetermined level value C and the DC component value D obtained by the above integration is obtained, and the difference signal E is fed back to the comparator means. The difference signal E is
In the signal obtained by AC coupling the reproduction signal of the recording medium on which the mark length is recorded, {(the maximum amplitude level value on the plus side)
+ (Minus-side amplitude maximum level value)} / {(plus-side amplitude maximum level value)-(minus-side amplitude maximum level value)}-α2 (however, α2 ≧ 0), the calculated value G is G ≧ 0
In the case of G, the reproduction inversion signal in which the polarity of the AC-coupled reproduction signal from the recording medium in which the mark length is recorded is inverted is selected as the input signal A, and in the case of G ≦ 0, the reproduction signal from the recording medium in which the mark length is recorded is selected. The AC-coupled reproduction signal of the input signal A
Select as and switch input.

In the information reproducing apparatus of the above (7), when the mark length is recorded and the recording section discriminates the original information from the reproduction signal of the recording medium such that the output signal increases with respect to the unrecorded section, reproduction is performed. , If the input signal A is higher than the first predetermined level value B, the low level signal is output. Conversely, if the input signal A is lower than the first predetermined level value B, the level value is decreased with the increase of the output time. Such a high level signal is output, the output signal is integrated, the difference between the second predetermined level value C and the DC component value D obtained by the above integration is obtained, and the difference signal E is fed back to the comparator means. In this case, the difference signal E is set to C−D, and {(plus side maximum amplitude level value) + (minus side maximum amplitude level) of the shortest mark in the signal obtained by AC coupling the reproduction signal of the recording medium on which the mark length is recorded. value)}/
If the calculated value H of {(amplitude maximum level value on the plus side) − (amplitude maximum level value on the minus side)} is H ≦ 0, the polarity of the AC-coupled reproduction signal from the recording medium on which the mark length is recorded. Is selected as the input signal A, and when H ≧ 0, the AC-coupled reproduction signal from the recording medium on which the mark length is recorded is selected as the input signal A and switched and input.

In the information reproducing apparatus of the above (8), when the mark length is recorded and the recording portion discriminates the original information from the reproduction signal of the recording medium such that the output signal increases with respect to the unrecorded portion, reproduction is performed. , If the input signal A is higher than the first predetermined level value B, the low level signal is output. Conversely, if the input signal A is lower than the first predetermined level value B, the level value is decreased with the increase of the output time. Such a high level signal is output, the output signal is integrated, the difference between the second predetermined level value C and the DC component value D obtained by the above integration is obtained, and the difference signal E is fed back to the comparator means. In this case, the difference signal E is set to CD, and the AC-coupled reproduction signal from the recording medium on which the mark length is recorded is set as the input signal A without changing the polarity, and the polarity is inverted to the input signal A. , And the slice offset signal Selectively inputting ≧ 0 and becomes better as the input signal A.

In the information reproducing apparatus of the above (9), when the mark length is recorded and the recording section discriminates the original information from the reproduction signal of the recording medium such that the output signal is lower than that of the unrecorded section, reproduction is performed. , If the input signal A is lower than the first predetermined level value B, the low level signal is output. Conversely, if the input signal A is higher than the first predetermined level value B, the level value is decreased with the increase of the output time. Such a high level signal is output, the output signal is integrated, the difference between the second predetermined level value C and the DC component value D obtained by the above integration is obtained, and the difference signal E is fed back to the comparator means. At that time, the difference signal E is set to D-C, and (shortest mark amplitude center level value)-(longest mark amplitude center level value) -α1 (where α1 ≧ 0) in the reproduction signal of the recording medium on which the mark length is recorded. When the calculated value F is F ≧ 0, A from the recording medium recorded
A reproduction inversion signal obtained by inverting the polarity of the C-coupled reproduction signal is selected as the input signal A, and when F ≦ 0, an AC-coupled reproduction signal from the recording medium on which the mark length is recorded is selected as the input signal A. Then switch input.

In the information reproducing apparatus of the above (10), when the mark length is recorded and the recording portion discriminates the original information from the reproduction signal of the recording medium such that the output signal is lower than that of the unrecorded portion, the information is reproduced. , If the input signal A is lower than the first predetermined level value B, the low level signal is output. Conversely, if the input signal A is higher than the first predetermined level value B, the level value is decreased with the increase of the output time. Such a high level signal is output, the output signal is integrated, the difference between the second predetermined level value C and the DC component value D obtained by the above integration is obtained, and the difference signal E is fed back to the comparator means. The difference signal E is D-C
In the signal obtained by AC coupling the reproduction signal of the recording medium on which the mark length is recorded, {(the maximum amplitude level value on the plus side)
+ (Minus-side amplitude maximum level value)} / {(plus-side amplitude maximum level value)-(minus-side amplitude maximum level value)} + α2 (however, α2 ≧ 0), the calculated value G is G ≦ 0
In the case of, the reproduction inversion signal in which the polarity of the AC-coupled reproduction signal from the recording medium in which the mark length is recorded is inverted is selected as the input signal A, and in the case of G ≧ 0, the reproduction signal from the recording medium in which the mark length is recorded is selected. The AC-coupled reproduction signal of the input signal A
Select as and switch input.

In the information reproducing apparatus of the above (11), when the mark length is recorded and the recording section discriminates the original information from the reproduction signal of the recording medium such that the output signal is lower than that of the unrecorded section, reproduction is performed. , If the input signal A is lower than the first predetermined level value B, the low level signal is output. Conversely, if the input signal A is higher than the first predetermined level value B, the level value is decreased with the increase of the output time. Such a high level signal is output, the output signal is integrated, the difference between the second predetermined level value C and the DC component value D obtained by the above integration is obtained, and the difference signal E is fed back to the comparator means. The difference signal E is D-C
And {(amplitude maximum amplitude level value on the plus side) + (amplitude maximum amplitude level value on the minus side)} / of the shortest mark in the signal obtained by AC coupling the reproduction signal of the recording medium on which the mark length is recorded.
When the calculated value H of {(plus side amplitude maximum level value) − (minus side amplitude maximum level value)} is H ≧ 0, the polarity of the AC-coupled reproduction signal from the recording medium on which the mark length is recorded Is selected as the input signal A, and when H ≦ 0, the AC-coupled reproduced signal from the recording medium on which the mark length is recorded is selected as the input signal A and input for switching.

In the information reproducing apparatus of the above (12), when the mark length is recorded and the recording section discriminates the original information from the reproduction signal of the recording medium such that the output signal is lower than that of the unrecorded section, reproduction is performed. , If the input signal A is lower than the first predetermined level value B, the low level signal is output. Conversely, if the input signal A is higher than the first predetermined level value B, the level value is decreased with the increase of the output time. Such a high level signal is output, the output signal is integrated, the difference between the second predetermined level value C and the DC component value D obtained by the above integration is obtained, and the difference signal E is fed back to the comparator means. The difference signal E is D-C
And the case where the AC-coupled reproduction signal from the recording medium on which the mark length is recorded is used as the input signal A without changing the polarity,
The case where the polarity is inverted and the input signal A is switched is switched, and the one where the slice offset signal is ≦ 0 is selectively input as the input signal A.

In the information reproducing apparatus of the above (13), when the mark length is recorded and the recording portion discriminates the original information from the reproduction signal of the recording medium such that the output signal increases with respect to the unrecorded portion, the information is reproduced. , If the input signal A is lower than the first predetermined level value B, the low level signal is output. Conversely, if the input signal A is higher than the first predetermined level value B, the level value is decreased with the increase of the output time. Such a high level signal is output, the output signal is integrated, the difference between the second predetermined level value C and the DC component value D obtained by the above integration is obtained, and the difference signal E is fed back to the comparator means. The difference signal E is D-C
When the calculated value F of (shortest mark amplitude center level value) − (longest mark amplitude center level value) + α1 (where α1 ≧ 0) in the reproduction signal of the recording medium on which the mark length is recorded is F ≦ 0, A from the recording medium on which the mark length is recorded
The C-coupled reproduction signal is selected as the input signal A, and F ≧
In the case of 0, a reproduction inversion signal obtained by inverting the polarity of the AC-coupled reproduction signal from the recording medium in which the mark length is recorded is selected as the input signal A and is switched and input.

In the information reproducing apparatus of the above (14), when the mark length is recorded and the recording portion discriminates the original information from the reproduction signal of the recording medium such that the output signal increases with respect to the unrecorded portion, reproduction is performed. , If the input signal A is lower than the first predetermined level value B, the low level signal is output. Conversely, if the input signal A is higher than the first predetermined level value B, the level value is decreased with the increase of the output time. Such a high level signal is output, the output signal is integrated, the difference between the second predetermined level value C and the DC component value D obtained by the above integration is obtained, and the difference signal E is fed back to the comparator means. The difference signal E is D-C
In the signal obtained by AC coupling the reproduction signal of the recording medium on which the mark length is recorded, {(the maximum amplitude level value on the plus side)
+ (Minus-side amplitude maximum level value)} / {(plus-side amplitude maximum level value)-(minus-side amplitude maximum level value)}-α2 (however, α2 ≧ 0), the calculated value G is G ≧ 0
In the case of, the AC-coupled reproduction signal from the recording medium in which the mark length is recorded is selected as the input signal A. In the case of G ≦ 0, the AC-coupled reproduction signal from the recording medium in which the mark length is recorded is selected. Playback inversion signal with inverted polarity is input signal A
Select as and switch input.

In the information reproducing apparatus of the above (15), when the mark length is recorded and the recording portion discriminates the original information from the reproduction signal of the recording medium such that the output signal increases with respect to the unrecorded portion, the information is reproduced. , If the input signal A is lower than the first predetermined level value B, the low level signal is output. Conversely, if the input signal A is higher than the first predetermined level value B, the level value is decreased with the increase of the output time. Such a high level signal is output, the output signal is integrated, the difference between the second predetermined level value C and the DC component value D obtained by the above integration is obtained, and the difference signal E is fed back to the comparator means. The difference signal E is D-C
And {(amplitude maximum amplitude level value on the plus side) + (amplitude maximum amplitude level value on the minus side)} / of the shortest mark in the signal obtained by AC coupling the reproduction signal of the recording medium on which the mark length is recorded.
When the calculated value H of {(amplitude maximum level value on the plus side)-(amplitude maximum level value on the minus side)} is H≤0, an AC-coupled reproduction signal from the recording medium on which the mark length is recorded is input. When the signal A is selected and H ≧ 0, a reproduction inversion signal obtained by inverting the polarity of the AC-coupled reproduction signal from the recording medium on which the mark length is recorded is selected as the input signal A and input for switching.

In the information reproducing apparatus of the above (16), when the mark length is recorded and the recording section discriminates the original information from the reproduction signal of the recording medium such that the output signal increases with respect to the unrecorded section, reproduction is performed. , If the input signal A is lower than the first predetermined level value B, the low level signal is output. Conversely, if the input signal A is higher than the first predetermined level value B, the level value is decreased with the increase of the output time. Such a high level signal is output, the output signal is integrated, the difference between the second predetermined level value C and the DC component value D obtained by the above integration is obtained, and the difference signal E is fed back to the comparator means. The difference signal E is D-C
And the case where the AC-coupled reproduction signal from the recording medium on which the mark length is recorded is used as the input signal A without changing the polarity,
The case where the polarity is inverted and the input signal A is switched is switched, and the one where the slice offset signal is ≦ 0 is selectively input as the input signal A.

[0045]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of an auto slice circuit which is an embodiment of the information reproducing apparatus of the present invention. This auto slice circuit
It comprises a comparator 1, an integrating circuit 2 and a subtracting circuit 3. The basic operation is to input an input signal (HF signal) S1 which is a reproduced signal reproduced from a recording medium to the comparator 1 and to output a comparator output signal S2 which is its output signal. Is input to the integrating circuit 2. The integrating circuit 2 outputs the comparator output signal S2
Is subjected to integration processing, and the integrated signal S3 is output to the subtraction circuit 3. Then, in the subtraction circuit 3, the DC offset signal S4 and the integration signal S3 which is the output signal from the integration circuit 2
The subtracted signal of and is fed back to the comparator 1 as the slice offset signal S5.

In this auto slicing circuit, the comparator output signal S2 from the comparator 1 is not a perfect rectangular wave, but its high level value is changed by the decrease of the frequency of the input signal S1 (increase of the output time of the comparator 1). Even if the recording state is deviated from the optimum state by setting to decrease and inverting the polarity of the input signal S1 input to the comparator 1 in accordance with the recording state judged from the reproduction signal, The error rate can be suppressed low.

For this purpose, the voltage magnitude relationship between the recorded portion (mark portion) and the unrecorded portion (space portion) of the reproduced signal obtained from the recording medium, the polarity of the signal from the recording medium input to the auto slice circuit, or the comparator. The polarity of 1 (the input signal (HF signal) S1 and the slice offset signal S5 are compared, and when the input signal> the slice offset signal, the output is a low level value, and when the input signal <the slice offset signal, the output is the high level value. Or
Alternatively, when the input signal> the slice offset signal, the output has a high level value, and when the input signal <the slice offset signal, the output has a low level value, or the polarity in the subtraction circuit 3 (the slice offset signal S5 is the DC offset signal S4)-(integration signal S3) or a combination of (integration signal S3)-(DC offset signal S4)) is used for classification. This is because the combination of the above makes the polarity of the input signal S1 of the comparator 1 and the determination criteria (eg, F,
This is because the directions of the inequality signs (G, H) are different.

For easy understanding of the description, the voltage magnitude relationship between the recorded portion (mark portion) and the unrecorded portion (space portion) of the input (HF signal: reproduced signal) S1 obtained from the recording medium is represented by A, and the recording portion AA indicates that the (mark part) has a voltage lower than that of the unrecorded part (space part), and conversely, the recorded part (mark part) has a signal whose voltage increases more than that of the unrecorded part (space part). The case is represented by AB. The polarity of the input signal S1 from the recording medium input to the auto slice circuit is represented by B, and when the polarity of the AC-coupled reproduction signal obtained from the recording medium is inverted to be the input signal to the auto slice circuit, BA, Conversely, when the AC-coupled reproduction signal obtained from the recording medium is directly used as the input signal to the auto slice circuit, it is represented by BB. The input signal to the auto slicing circuit may be the signal itself obtained from S1, the recording medium, or the signal after processing such as waveform equalization.

The polarity of the comparator 1 is represented by C, and the input signal (HF signal) S1 is compared with the slice offset signal S5. When the input signal> the slice offset signal, the output is a low level value, and when the input signal <the slice offset signal, CA when the output has a high level value, conversely, when the input signal> the slice offset signal, the output has a high level value,
When the input signal is smaller than the slice offset signal and the output has a low level value, it is represented by CB. The polarity in the subtraction circuit 3 is represented by D, and DA when the slice offset signal S5 is (DC offset signal S4)-(integration signal S3),
Conversely, DB is used when (integral signal S3)-(DC offset signal S4). According to this notation, the combination of A, B, C, and D, which is significant as an auto slice circuit, is the combination shown in FIG.

The combinations according to claims 1 to 4 of the present invention are AA-BX (X represents A or B) -CA-D.
In the case of A, when reproducing a recording portion recorded with a high recording power, X is set to A (combination No. 1 in FIG. 2),
When reproducing the recording portion recorded with the low recording power, X is set to B (combination No. 2 in FIG. 2). Further, the combination according to claims 5 to 8 of the present invention is AB-BX (X
Represents A or B) -CA-DA, and when reproducing a recording portion recorded with high recording power, X is set to B (combination No. 6 in FIG. 2) and recording is performed with low recording power. When reproducing the recorded portion, X is set to A (combination No. 5 in FIG. 2).

Further, the combinations according to claims 9 to 12 of the present invention are AA-BX (X represents A or B).
In the case of -CB-DB, when reproducing a recording portion recorded with high recording power, X is set to B (combination N in FIG.
o. 4) When reproducing the recording portion recorded with the low recording power, X is set to A (combination No. 3 in FIG. 2). Furthermore, the combinations according to claims 13 to 16 of the present invention are AB-BX (X represents A or B) -CB-D.
In the case of B, when reproducing the recording portion recorded with high recording power, X is set to A (combination No. 7 in FIG. 2),
When reproducing the recording portion recorded with the low recording power, X is set to B (combination No. 8 in FIG. 2).

As a function according to claim 1 of the present invention, the auto slicing circuit records the mark length, and the recording portion reproduces the original signal from the reproduction signal of the recording medium such that the output signal is lower than that of the unrecorded portion. As an auto slice circuit of an information reproducing apparatus for discriminating and reproducing information of
Is higher than the first predetermined level value B, a low level signal is output when it is lower than the first predetermined level value B, and a high level signal whose level value is decreased as the output time is increased. A comparator 1 that functions as a comparator that outputs the respective signals, an integrating circuit 2 that functions as an integrating unit that integrates the output signal output by the comparator 1, and a second predetermined level value C and an integration process by the integrating circuit 2. The subtraction circuit 3 having a function of obtaining a difference signal E from the DC component value D obtained by
Is fed back to the comparator 1. The difference signal E fed back to the comparator 1 is set to (the second predetermined level value C)-(the DC component value D), and the difference signal E Center level value)-(longest mark amplitude center level value) -Offset value α1 (where α1 ≧
When the calculated value F of 0) is 0 or more (F ≧ 0), a signal obtained by AC coupling the reproduction signal is selected as the input signal A, and when it is not 0 or more (F ≦ 0), the reproduction signal is AC.
The reproduction inversion signal in which the polarity is combined and the polarity is inverted is used as the input signal A.
Is selected and input is switched for each.

Further, as a function according to claim 2 of the present invention, the auto slice circuit records mark length,
The recording section is an auto-slice circuit of an information reproducing apparatus which discriminates the original information from the reproduction signal of the recording medium such that the output signal is lower than that of the unrecorded section and reproduces the original information. When it is higher than B, a low level signal is output, and when it is lower than the first predetermined level value B, a high level signal is output so that the level value decreases as the output time increases. Comparator 1 having a function, integrating circuit 2 having a function of integrating means for integrating an output signal output from comparator 1, second predetermined level value C and a DC component value obtained by integration processing by integrating circuit 2. The subtraction circuit 3 has a function of obtaining a difference signal E from D, and is configured to feed back the difference signal E to the comparator 1 and feed back to the comparator 1. The signal E (the second predetermined level value C) - to (the DC component value D), the reproduced signal A
In the C-coupled signal, {(plus amplitude maximum level value) + (minus amplitude maximum level value)} / {(plus amplitude maximum level value) − (minus amplitude maximum level value)} + offset When the calculated value G having the value α2 (where α2 ≧ 0) is 0 or less (G ≦ 0), the reproduction signal is AC.
The combined signal is selected as the input signal A, and when it is not 0 or less (G ≧ 0), the reproduction inversion signal in which the reproduction signal is AC-coupled and the polarity is inverted is selected as the input signal A, and each of them is switched and input. It is something that is done.

Further, as a function according to claim 3 of the present invention, in the auto slice circuit, the mark length is recorded, and the recording portion reproduces the original signal from the reproduction signal of the recording medium in which the output signal is lower than that of the unrecorded portion. As an auto slice circuit of an information reproducing apparatus for discriminating and reproducing information of
Is higher than the first predetermined level value B, a low level signal is output when it is lower than the first predetermined level value B, and a high level signal whose level value is decreased as the output time is increased. A comparator 1 that functions as a comparator that outputs the respective signals, an integrating circuit 2 that functions as an integrating unit that integrates the output signal output by the comparator 1, and a second predetermined level value C and an integration process by the integrating circuit 2. The subtraction circuit 3 having a function of obtaining a difference signal E from the DC component value D obtained by
Is fed back to the comparator 1, the difference signal E fed back to the comparator 1 is set to (the second predetermined level value C) − (the DC component value D), and the reproduction signal is AC-coupled. Calculated value of the shortest mark in {(plus side amplitude maximum level value) + (minus side amplitude maximum level value)} / {(plus side amplitude maximum level value) − (minus side amplitude maximum level value)} H is 0 or more (H
In the case of ≧ 0, a signal obtained by AC coupling the reproduction signal is selected as the input signal A. When it is not 0 or more (H ≦ 0), a reproduction inversion signal obtained by AC coupling the reproduction signal and inverting the polarity is selected. The input signal A is selected and switched for input.

As a function according to claim 4 of the present invention, the auto slice circuit records mark length,
The recording section is an auto-slice circuit of an information reproducing apparatus which discriminates the original information from the reproduction signal of the recording medium such that the output signal is lower than that of the unrecorded section and reproduces the original information. When it is higher than B, a low level signal is output, and when it is lower than the first predetermined level value B, a high level signal is output so that the level value decreases as the output time increases. Comparator 1 having a function, integrating circuit 2 having a function of integrating means for integrating an output signal output from comparator 1, second predetermined level value C and a DC component value obtained by integration processing by integrating circuit 2. The subtraction circuit 3 has a function of obtaining a difference signal E from D, and is configured to feed back the difference signal E to the comparator 1 and feed back to the comparator 1. The signal E (the second predetermined level value C) - to (the DC component value D), the reproduced signal A
The signal that does not change the polarity by C-coupling and the reproduced signal is AC
Of either one of the combined and inverted polarity signals (the second predetermined level value C) − (the DC component value D)
The input signal A is selected so that the input signal becomes 0 or more and is input.

Further, as a function according to claim 5 of the present invention, the auto slicing circuit records the mark length, and the recording portion reproduces the original signal from the reproduction signal of the recording medium such that the output signal increases with respect to the unrecorded portion. As an auto slice circuit of an information reproducing apparatus for discriminating and reproducing information of
Is higher than the first predetermined level value B, a low level signal is output when it is lower than the first predetermined level value B, and a high level signal whose level value is decreased as the output time is increased. A comparator 1 that functions as a comparator that outputs the respective signals, an integrating circuit 2 that functions as an integrating unit that integrates the output signal output by the comparator 1, and a second predetermined level value C and an integration process by the integrating circuit 2. The subtraction circuit 3 having a function of obtaining a difference signal E from the DC component value D obtained by
Is fed back to the comparator 1. The difference signal E fed back to the comparator 1 is set to (the second predetermined level value C)-(the DC component value D), and the difference signal E (Center level value)-(longest mark amplitude center level value) + offset value α1 (where α1 ≧
When the calculated value F of 0) is 0 or less (F ≦ 0), the reproduction inversion signal obtained by AC coupling the reproduction signal and inverting the polarity is selected as the input signal A, and is not 0 or less (F ≧ 0). In this case, a signal obtained by AC-coupling the reproduction signal is selected as the input signal A and is switched and input.

As a function according to claim 6 of the present invention, the auto slice circuit records mark length,
The recording unit is an auto-slice circuit of an information reproducing apparatus that discriminates and reproduces original information from a reproduction signal of a recording medium such that an output signal increases with respect to an unrecorded portion, and the input signal A is a first predetermined level value. When it is higher than B, a low level signal is output, and when it is lower than the first predetermined level value B, a high level signal is output so that the level value decreases as the output time increases. Comparator 1 having a function, integrating circuit 2 having a function of integrating means for integrating an output signal output from comparator 1, second predetermined level value C and a DC component value obtained by integration processing by integrating circuit 2. The subtraction circuit 3 has a function of obtaining a difference signal E from D, and is configured to feed back the difference signal E to the comparator 1 and feed back to the comparator 1. The signal E (the second predetermined level value C) - to (the DC component value D), the reproduced signal A
{(Plus amplitude maximum level value) + (minus amplitude maximum level value)} / {(plus amplitude maximum level value) − (minus amplitude maximum level value)} − offset in C-coupled signal When the calculated value G having the value α2 (where α2 ≧ 0) is 0 or more (G ≧ 0), the reproduction signal is AC.
The reproduction inversion signal in which the polarity is combined and the polarity is inverted is used as the input signal A.
If it is not 0 or more (G ≦ 0), a signal obtained by AC-coupling the reproduction signal is selected as the input signal A and is switched and input.

Further, as a function according to claim 7 of the present invention, in the auto slice circuit, the mark length is recorded, and the recording portion reproduces an original signal from a reproduction signal of a recording medium in which an output signal is increased with respect to an unrecorded portion. As an auto slice circuit of an information reproducing apparatus for discriminating and reproducing information of
Is higher than the first predetermined level value B, a low level signal is output when it is lower than the first predetermined level value B, and a high level signal whose level value is decreased as the output time is increased. A comparator 1 that functions as a comparator that outputs the respective signals, an integrating circuit 2 that functions as an integrating unit that integrates the output signal output by the comparator 1, and a second predetermined level value C and an integration process by the integrating circuit 2. The subtraction circuit 3 having a function of obtaining a difference signal E from the DC component value D obtained by
Is fed back to the comparator 1, the difference signal E fed back to the comparator 1 is set to (the second predetermined level value C) − (the DC component value D), and the reproduction signal is AC-coupled. Calculated value of the shortest mark in {(plus side amplitude maximum level value) + (minus side amplitude maximum level value)} / {(plus side amplitude maximum level value) − (minus side amplitude maximum level value)} H is 0 or less (H
In the case of ≦ 0), a reproduction inversion signal in which the reproduction signal is AC-coupled and the polarity is inverted is selected as the input signal A. When it is not 0 or less (H ≧ 0), a signal in which the reproduction signal is AC-coupled is selected. The input signal A is selected and switched for input.

Further, as a function according to claim 8 of the present invention, the auto slice circuit records mark length,
The recording unit is an auto-slice circuit of an information reproducing apparatus that discriminates and reproduces original information from a reproduction signal of a recording medium such that an output signal increases with respect to an unrecorded portion, and the input signal A is a first predetermined level value. When it is higher than B, a low level signal is output, and when it is lower than the first predetermined level value B, a high level signal is output so that the level value decreases as the output time increases. Comparator 1 having a function, integrating circuit 2 having a function of integrating means for integrating an output signal output from comparator 1, second predetermined level value C and a DC component value obtained by integration processing by integrating circuit 2. The subtraction circuit 3 has a function of obtaining a difference signal E from D, and is configured to feed back the difference signal E to the comparator 1 and feed back to the comparator 1. The signal E (the second predetermined level value C) - to (the DC component value D), the reproduced signal A
The signal that does not change the polarity by C-coupling and the reproduced signal is AC
Of either one of the combined and inverted polarity signals (the second predetermined level value C) − (the DC component value D)
The input signal A is selected so that the input signal becomes 0 or more and is input.

Further, as a function according to claim 9 of the present invention, the auto slicing circuit records the mark length, and the recording portion reproduces the original signal from the reproduction signal of the recording medium such that the output signal is lower than that of the unrecorded portion. As an auto slice circuit of an information reproducing apparatus for discriminating and reproducing information of
Is lower than the first predetermined level value B, a low level signal is output when the output level is higher than the first predetermined level value B, and a high level signal is output when the output time is increased. A comparator 1 that functions as a comparator that outputs the respective signals, an integrating circuit 2 that functions as an integrating unit that integrates the output signal output by the comparator 1, and a second predetermined level value C and an integration process by the integrating circuit 2. The subtraction circuit 3 having a function of obtaining a difference signal E from the DC component value D obtained by
Is fed back to the comparator 1, and the difference signal E fed back to the comparator 1 (the DC component value D)
-(The second predetermined level value C), (the shortest mark amplitude center level value)-(the longest mark amplitude center level value) -the offset value α1 (where α1 ≧
When the calculated value F of 0) is 0 or more (F ≧ 0), the reproduction inversion signal in which the reproduction signal is AC-coupled and the polarity is inverted is selected as the input signal A, and is not 0 or more (F ≦ 0). In this case, a signal obtained by AC-coupling the reproduced signal is selected as the input signal A and is switched and input.

Further, as a function according to claim 10 of the present invention, in the auto slice circuit, the mark length is recorded, and the recording portion is reproduced from the reproduction signal of the recording medium such that the output signal is lower than that of the unrecorded portion. As an auto slice circuit of an information reproducing apparatus for discriminating and reproducing information of
Is lower than the first predetermined level value B, a low level signal is output when the output level is higher than the first predetermined level value B, and a high level signal is output when the output time is increased. A comparator 1 that functions as a comparator that outputs the respective signals, an integrating circuit 2 that functions as an integrating unit that integrates the output signal output by the comparator 1, and a second predetermined level value C and an integration process by the integrating circuit 2. The subtraction circuit 3 having a function of obtaining a difference signal E from the DC component value D obtained by
Is fed back to the comparator 1, and the difference signal E fed back to the comparator 1 (the DC component value D)
-(The second predetermined level value C), and {(plus amplitude maximum level value on the plus side) + (minus amplitude maximum level value)} / {(amplitude on the plus side in the signal obtained by AC coupling the reproduced signal (Maximum level value) − (minus side amplitude maximum level value)} + offset value α2 (where α2 ≧ 0) When the calculated value G is 0 or less (G ≦ 0), the reproduction signal is A
A reproduction inversion signal in which the polarity is inverted by C coupling is selected as the input signal A, and when it is not 0 or less (G ≧ 0), a signal obtained by AC coupling the reproduction signal is selected as the input signal A and switched. It is the one that is input.

Further, as a function according to an eleventh aspect of the present invention, the auto slicing circuit records the mark length, and the recorded portion is reproduced from the reproduction signal of the recording medium whose output signal is lower than that of the unrecorded portion. As an auto slice circuit of an information reproducing apparatus for discriminating and reproducing information of
Is lower than the first predetermined level value B, a low level signal is output when the output level is higher than the first predetermined level value B, and a high level signal is output when the output time is increased. A comparator 1 that functions as a comparator that outputs the respective signals, an integrating circuit 2 that functions as an integrating unit that integrates the output signal output by the comparator 1, and a second predetermined level value C and an integration process by the integrating circuit 2. The subtraction circuit 3 having a function of obtaining a difference signal E from the DC component value D obtained by
Are fed back to the comparator means, the difference signal E fed back to the comparator 1 is set to (the DC component value D)-(the second predetermined level value C), and the reproduction signal is AC-coupled. Of the shortest mark in the generated signal {(plus side maximum amplitude level value) + (minus side maximum amplitude level value)} / {(plus side maximum amplitude level value)-
(The maximum amplitude level value on the minus side)} is 0.
In the above case (H ≧ 0), the reproduction signal is AC-coupled and the polarity is inverted, and the reproduction inversion signal is selected as the input signal A. When it is not 0 or more (H ≦ 0), the reproduction signal is AC.
The combined signal is selected as the input signal A and switched and input.

According to a twelfth aspect of the present invention, the auto slicing circuit records the mark length, and the recording portion reproduces the original signal from the reproduction signal of the recording medium in which the output signal is lower than that of the unrecorded portion. As an auto slice circuit of an information reproducing apparatus for discriminating and reproducing information of
Is lower than the first predetermined level value B, a low level signal is output when the output level is higher than the first predetermined level value B, and a high level signal is output when the output time is increased. A comparator 1 that functions as a comparator that outputs the respective signals, an integrating circuit 2 that functions as an integrating unit that integrates the output signal output by the comparator 1, and a second predetermined level value C and an integration process by the integrating circuit 2. The subtraction circuit 3 having a function of obtaining a difference signal E from the DC component value D obtained by
Is fed back to the comparator 1, and the difference signal E fed back to the comparator 1 (the DC component value D)
-(The second predetermined level value C), the reproduction signal is AC-coupled and the polarity is not changed, and the reproduction signal is A
Of either of the signal which is C-coupled and whose polarity is inverted (the above DC component value D)-(the above second predetermined level value C)
The input signal A is selected so that the input signal becomes 0 or less and is input.

Further, as a function according to a thirteenth aspect of the present invention, the auto slicing circuit records the mark length, and the recording portion is reproduced from the reproduction signal of the recording medium in which the output signal is increased with respect to the unrecorded portion. As an auto slice circuit of an information reproducing apparatus for discriminating and reproducing information of
Is lower than the first predetermined level value B, a low level signal is output when the output level is higher than the first predetermined level value B, and a high level signal is output when the output time is increased. A comparator 1 that functions as a comparator that outputs the respective signals, an integrating circuit 2 that functions as an integrating unit that integrates the output signal output by the comparator 1, and a second predetermined level value C and an integration process by the integrating circuit 2. The subtraction circuit 3 having a function of obtaining a difference signal E from the DC component value D obtained by
Is fed back to the comparator 1, and the difference signal E fed back to the comparator 1 (the DC component value D)
-(The second predetermined level value C), and the (shortest mark amplitude center level value)-(longest mark amplitude center level value) + offset value α1 (where α1 ≧
When the calculated value F of 0) is 0 or less (F ≦ 0), the signal obtained by AC-coupling the reproduction signal is selected as the input signal A, and when it is not 0 or less (F ≧ 0), the reproduction signal is AC.
The reproduction inversion signal in which the polarity is combined and the polarity is inverted is used as the input signal A.
Is selected and input is switched for each.

As a function according to a fourteenth aspect of the present invention, the auto slicing circuit records the mark length, and the recording portion is reproduced from the reproduction signal of the recording medium in which the output signal is increased with respect to the unrecorded portion. As an auto slice circuit of an information reproducing apparatus for discriminating and reproducing information of
Is lower than the first predetermined level value B, a low level signal is output when the output level is higher than the first predetermined level value B, and a high level signal is output when the output time is increased. A comparator 1 that functions as a comparator that outputs the respective signals, an integrating circuit 2 that functions as an integrating unit that integrates the output signal output by the comparator 1, and a second predetermined level value C and an integration process by the integrating circuit 2. The subtraction circuit 3 having a function of obtaining a difference signal E from the DC component value D obtained by
Is fed back to the comparator 1, and the difference signal E fed back to the comparator 1 (the DC component value D)
-(The second predetermined level value C), and {(amplitude maximum amplitude level value on the plus side) + (minus amplitude maximum level value)} / {(amplitude on the plus side) in the signal obtained by AC coupling the reproduction signal Maximum level value)-(minus side amplitude maximum level value)}-offset value α2 (where α2 ≧ 0) when the calculated value G is 0 or more (G ≧ 0), the reproduction signal is set to A
The C-coupled signal is selected as the input signal A, and when it is not 0 or more (G ≦ 0), the reproduction inversion signal in which the reproduction signal is AC-coupled and the polarity is inverted is selected as the input signal A and switched. It is the one that is input.

Further, as a function according to a fifteenth aspect of the present invention, in the auto slice circuit, the mark length is recorded, and the recording portion reproduces from the reproduction signal of the recording medium such that the output signal increases with respect to the unrecorded portion. As an auto slice circuit of an information reproducing apparatus for discriminating and reproducing information of
Is lower than the first predetermined level value B, a low level signal is output when the output level is higher than the first predetermined level value B, and a high level signal is output when the output time is increased. Comparator 1 that performs the function of the comparator unit that outputs the respective signals, and integration circuit 2 that performs the function of the integration unit that integrates the output signal output by the comparator 1, the second predetermined level value C and the integration by the integration circuit 2. Difference signal E from DC component value D obtained by processing
And a subtraction circuit 3 that performs the function of obtaining the difference signal E, and is configured to feed back the difference signal E to the comparator 1. The difference signal E fed back to the comparator 1 is (the DC component value D) − (the above-mentioned 2) and the reproduction signal is AC-coupled and the shortest mark {(plus side amplitude maximum level value) + (minus side amplitude maximum level value)} / {(plus side amplitude maximum) Level value)-(maximum amplitude level value on the minus side)} When the calculated value H is 0 or less (H≤0), the signal obtained by AC coupling the above reproduction signal is selected as the input signal A and is not 0 or less. (H ≧ 0)
In this case, the reproduction inversion signal in which the reproduction signal is AC-coupled and the polarity is inverted is selected as the input signal A and is switched and input.

Furthermore, as a function according to a sixteenth aspect of the present invention, the auto slicing circuit records the mark length, and the recording portion reproduces the reproduction signal of the recording medium such that the output signal increases with respect to the unrecorded portion. As an auto slice circuit of an information reproducing apparatus for discriminating and reproducing original information, when an input signal A is lower than a first predetermined level value B, a low level signal is higher than the first predetermined level value B. In this case, the comparator 1 functions as a comparator that outputs a high-level signal whose level value decreases as the output time increases, and the function of an integrator that integrates the output signal output by the comparator 1. And the function of obtaining the difference signal E between the second predetermined level value C and the DC component value D obtained by the integration processing by the integration circuit 2. Plus and a subtraction circuit 3, and configured to return the difference signal E to the comparator 1,
The difference signal E fed back to the comparator 1 is set to (the DC component value D) − (the second predetermined level value C), and the reproduction signal is AC-coupled so as not to change the polarity, and the reproduction signal is AC-coupled. Of the signals whose polarity has been inverted, the one in which (the above-mentioned DC component value D)-(the above-mentioned second predetermined level value C) becomes 0 or less is selected and input as the above-mentioned input signal A. It is something that is done.

Next, the comparator output signal S2 from the comparator 1 in this auto slicing circuit is not a perfect rectangular wave, but its high (High) due to the decrease of the frequency of the input signal S1 (increase of the output time of the comparator 1).
h) The operation when the level value is set to decrease will be described. In the following description, as the configuration of the auto slice circuit, in the case of AA-BA-CA-DA, that is, from the recording medium, the voltage of the recorded portion (mark portion) is higher than that of the unrecorded portion (space portion). A signal that decreases is obtained, and the polarity inversion signal of the AC-coupled signal from the recording medium is used as the input signal (HF signal) S1 of the comparator 1,
The slice offset signal S5 (DC offset signal S
4)-(integrated signal S2), the comparator 1 compares the input signal (HF signal) S1 with the slice offset signal S5, and when the input signal> the slice offset signal, the output is a low level value (for example, 0 (V)). , When the input signal <slice offset signal, the output is a high level value (for example, +
A case of outputting an output signal of 5 (V) will be described.

FIG. 3 is a waveform diagram showing signals of respective parts in the auto slice circuit shown in FIG. In the figure, since the high level value of the comparator output signal S2 output from the comparator 1 is considered to be VR and the low level value is 0 (V), the value of the DC offset signal S4 is equal to the low level voltage value + ((high level voltage Value)-(low level voltage value)) /
2 = VR / 2. FIG. 4 is a waveform diagram of the comparator output signal output from the comparator 1 shown in FIG.

Assuming that a signal as shown in FIG. 3A is an input signal (HF signal) S1, the comparator output signal S2 from the comparator 1 is not a perfect rectangular wave, but as shown in FIG. Then, a signal whose high level value decreases according to the frequency (input signal time) of the input signal S1 is output. It should be noted that the comparator output signal S2 from the comparator 1 referred to here is not a perfect rectangular wave, and its high level value decreases depending on the frequency of the input signal S1 (input signal time), as shown in FIG. Indicates that the high level value decreases with the signal time (however,
After the level value decreases to a certain level, it shows a constant value).

The integrating circuit 2 integrates (averages) the comparator output signal S2 shown in FIG. 3B.
Then, as shown in (c) of FIG. 3, a value V11 lower than the integrated value V1 obtained when the comparator output signal S2 from the comparator 1 is a complete rectangular wave with a constant high level voltage value VR (( However, when compared with the same slice offset voltage). The difference between the integrated values V1 and V11 is
When the input signal frequency is high (the input signal time is short), it increases as the input signal frequency becomes lower (the input signal time increases). While the slice level is set so that the lengths of the space part (unrecorded part) are almost equal, the input signal frequency is low frequency (input signal time is long)
In this case, the slice level is set so that the lengths of the mark portion (recording portion) and the space portion (unrecorded portion) recorded as the same length are greatly different (the output signal from the comparator 1 is the high level voltage value). In the case of a completely rectangular wave with a constant VR, such a slice level change due to the input signal frequency does not occur).

Therefore, this auto slice circuit is
The difference between the actual slice level and the original slice level depending on the frequency of the input signal, that is, the length of the mark or space, causes the error rate to be extremely high on the recording power side, which is higher than the recording power that minimizes jitter. Is low and the error rate fluctuation due to recording power fluctuation is small (playback has a wide recording power margin), or the error rate is extremely low on the recording power side lower than the recording power that minimizes jitter and recording Playback with a small error rate variation due to power variation (wide recording power margin of error rate) is possible.

Next, the above phenomenon will be described. In the case of an input signal composed of a plurality of mark lengths and space lengths, for example, EFM signals and D used in CD optical discs
In the case of 8-16 modulation used in a VD optical disk, microscopically, there are portions where many short marks are present in the input signal and portions where many short marks are not present in the input signal. Now, consider a case where a reproduction signal of a CD optical disk or a DVD optical disk is input to a conventional auto slice circuit. However, the configuration of the auto slice circuit is AA-
This will be described as BA-CA-DA.

FIG. 5 is a diagram schematically showing an eye pattern of a portion recorded with a recording power slightly lower than the optimum recording power, and FIG. 6 is a schematic diagram of an eye pattern of a portion recorded with the optimum recording power. FIG. 7 and FIG. 7 are diagrams schematically showing an eye pattern of a portion recorded with a recording power slightly higher than the optimum recording power. In addition, in FIGS. 5 to 7, the upper part of the drawing is a mark portion (indicating a high voltage value),
The lower part is drawn as a space part (showing a low voltage value). In each figure, the amplitude of the shortest mark, the average mark amplitude macroscopically, and the longest mark amplitude are shown. The macroscopic average mark is the average mark length (mark type) determined by the modulation method.
It means a value obtained by sequentially adding the lengths of marks that appear in a sufficiently long time observation and dividing it by the total number of marks that appeared. As an input signal, a region where many shortest marks are present (region A) and a region where few shortest marks are present (region B) are microscopically present (during a short time).

In FIG. 5, in a region where there are many shortest marks (region A), the microscopic average mark length in the region is almost equal to the macroscopic average mark length. A slice level value is set at the amplitude center of the average mark (slice level value A is set so that c = d). The microscopic average mark length is the average mark length (mark type) determined by the modulation method, and the mark lengths that appear during a finite short time observation are sequentially added, and Means the value divided by the total number of marks that appeared. On the other hand, in the area with the shortest mark (area B), the microscopic average mark length in that area is longer than the macroscopic average mark length, so the slice level value moves toward the center of amplitude of the longest mark. However, a slice level value B higher than the slice level value A is set.

However, since the microscopic average mark length becomes long in the area B, the slice level value actually set by the operation of the slice level value described above (the integrated value of the comparator output signal S2 decreases). , The slice level value C is higher than the slice level value B. Jitter is considered to have the minimum symmetry with respect to the slice level value of the shortest mark and the average mark having the highest frequency of occurrence when they are closest (that is, a = b and c = d). Area A (slice level value A) in FIG.
In the area B (slice level value C) in which the jitter level is slightly deteriorated and the slice level value for the shortest mark is largely deviated from the optimum state, the jitter is extremely deteriorated.

The error rate is particularly high in frequency of occurrence, and if the symmetry of the shortest mark having a narrow allowable slice level value range is greatly deviated from the slice level value (a> b, or b <a), it deteriorates. In the area A (slice level value A) in FIG. 5 where the slice level value for the shortest mark is slightly deviated from the optimum state, the error rate is slightly deteriorated, and the slice level value for the shortest mark is greatly deviated from the optimum state B (slice level value A). In C), the error rate will be greatly deteriorated.

In FIG. 6, in a region where there are many shortest marks (region A), the microscopic average mark length in the region is almost equal to the macroscopic average mark length. A slice level value is set at the amplitude center of the average mark (slice level value A is set so that c = d). On the other hand, the area with few shortest marks (area B)
Then, the microscopic average mark length in that area is longer than the macroscopically seen average mark length, but since the amplitude center of the average mark and the amplitude center of the longest mark are almost equal, it is equivalent to the slice level value A. The slice level value B is set. However, since the microscopic average mark length becomes long in this area B, the slice level value that is actually set is the slice level value that is actually set by the above-described operation of the slice level value (the integrated value of the comparator output signal S2 decreases). The slice level value C is higher than B.

Jitter is considered to have the minimum symmetry with respect to the slice level value of the shortest mark having the highest appearance frequency and the average mark when they are closest (that is, a = b and c = d). In the area A (slice level A) in which the slice level value is close to the optimum state, the jitter shows the minimum value, and in the area B (slice level value C) where the slice level values for the shortest mark and the average mark are slightly deviated from the optimum state. The jitter will be a little worse (but overall, it shows a good value).

The error rate has the highest frequency of occurrence, and if the symmetry of the shortest mark having a narrow allowable slice level value range is greatly deviated from the symmetry (a
> B or b <a), the error rate is very low (the error is very small) in the area A (slice level value A) of FIG. 6 where the slice level value for the shortest mark is close to the optimum state. In the area B (slice level value C) in which the slice level value for V is slightly deviated from the optimum state, the error rate is slightly deteriorated. Therefore, in this state, although the jitter shows the minimum value, the error rate does not show the minimum value.

In FIG. 7, in a region where there are many shortest marks (region A), the microscopic average mark length in the region is almost equal to the macroscopic average mark length, and therefore, the macroscopically viewed mark is used. A slice level value is set at the amplitude center of the average mark (slice level value A is set so that c = d). On the other hand, the area with few shortest marks (area B)
Then, since the microscopic average mark length in this area is longer than the macroscopic average mark length, the slice level value moves toward the center of the amplitude of the longest mark, and the slice level value lower than the slice level value A. The value B is set.

However, since the microscopic average mark length becomes long in this area B, the slice level value actually set by the above-described operation of the slice level value (the integrated value of the comparator output signal S2 decreases) is: The slice level value C is higher than the slice level value B, and the slice level value C is close to the slice level value A. Jitter is considered to have the minimum symmetry with respect to the slice level value of the shortest mark having the highest appearance frequency and the average mark when they are closest (that is, a = b and c = d). The jitter is slightly deteriorated in the area A (slice level value A) of FIG. 7 which is slightly deviated from the optimum state, and the jitter is slightly deteriorated even in the area B (slice level value C) of which the slice level value for the shortest mark is slightly deviated from the optimum state. become.

Further, the error rate is particularly high in the frequency of occurrence, and if the symmetry of the shortest mark having a narrow slice level value variation allowable range with respect to the slice level value is significantly deviated (a> b or b <a), the error rate deteriorates. , Area A in FIG. 7 in which the slice level value for the shortest mark is close to the optimum state
In (slice level value A), the error rate is low, and the slice level value for the shortest mark is near the optimum state in area B.
Even with (slice level value C), the error rate becomes low. Therefore, in this state, the jitter does not show the minimum value, but the error rate shows a low value. Due to the phenomenon that the slice level value difference between the area A and the area B becomes small on the high recording power side, the error rate becomes low even if the recording power fluctuates, and the jitter is deteriorated by the fluctuation of the recording power, but the error rate Remains low (this phenomenon does not occur when the comparator output signal S2 is a constant rectangular wave with a high level voltage value VR).

On the other hand, on the low recording power side, the slice level shift for the short mark in the area B shifts in a more inappropriate direction due to the attenuating property of the high level value output from the comparator 1. The rate rapidly deteriorates as the recording power decreases. In short, the phenomenon that the error rate does not increase due to recording power fluctuation is that the slice level value A in the area A is different from the area B in the area B.
Although the slice level value B in FIG. 2 shifts, the slice level value C (this slice level Value becomes the slice level value in area B).

In the above description based on FIGS. 5 to 7, it is on the high recording power side that the slice level value C shifts in the opposite direction to the direction in which the slice level value B shifts with respect to the slice level value A. It was Therefore, in the auto slicing circuit of this embodiment, the polarity C of the comparator 1 determines the slice level shift direction due to the attenuating property of the high level output voltage of the comparator 1, so that the shift direction and the entire slice level value are made to match. To That is, if the polarity of the input signal S1 of the comparator 1 is changed, the slice level value C shifts in the direction opposite to the slice level value B shift with respect to the slice level value A only on the low recording power side. You can

More specifically, AA-BX-CA-
In the case of DA, the slice level shift direction due to the attenuating property of the high-level output voltage of the comparator 1 is the plus direction as shown by the broken lines in FIGS. 8 and 9 (however, in FIGS. It is the figure which showed typically only the amplitude of the shortest mark and the long mark (= longest mark) which has the maximum amplitude in the signal which AC-coupled the reproduction signal. Therefore, it is necessary to set the overall slice level value to the plus side (that is, set the slice offset voltage ≧ 0).

In the case where BX is BA and the state is as shown in FIG. 8, the overall slice level value (indicated by the alternate long and short dash line in the figure) is on the minus side, and the overall slice level value and the comparator 1 Although the direction of the slice level shift value is different due to the attenuating property of the high level output voltage from, the polarity of the input signal S1 is inverted and BX is set to BB, so that the overall slice level value is changed as shown in FIG. By setting (indicated by a one-dot chain line in the figure) to the plus side, the direction of the overall slice level value and the slice level shift value due to the attenuation of the high level output voltage by the comparator 1 can be matched. As described above, a portion recorded with a recording power lower than the vicinity of the recording power at which the jitter becomes the minimum value has a low error rate, and even if the recording power changes, the error rate can be read in a low state.

Therefore, in the auto slice circuit of this embodiment, the polarity of the input signal of the comparator 1 is switched according to the state of the reproduced signal. In this way
Even in a portion recorded with a recording power higher than the recording power near the minimum jitter value, the error rate is low, and even if the recording power changes, the error rate can be read in a low error state, and the jitter minimum value The error rate is low even in a portion recorded with a recording power lower than the vicinity of the recording power
Even if the recording power changes, the data can be read with a low error rate. That is, when this auto slice circuit is used, the recording power margin at the time of recording can be substantially increased and the determination and control of the recording power for actual recording can be simplified.

The polarity of the input signal S1 of the comparator 1 is switched according to the state of the reproduced signal, and specifically, the following methods (1) to (2) are performed. The calculated value F of ((shortest mark amplitude center level value)-(longest mark amplitude center level value)) ± α1 (where α1 ≧ 0) in the reproduction signal of the recording medium on which the mark length is recorded is F ≧ 0. Or whether F ≦ 0 holds. For example, FIG. 10 is a waveform diagram for explaining the calculated value F, and in this case, the calculated value F = (((SH + S
L) / 2)-((LH + LL) / 2)) ± α1.

[(Plus maximum amplitude level value) + (Minus amplitude maximum level value)] / in the signal obtained by AC coupling the reproduction signal of the recording medium on which the mark length is recorded
{(Amplitude maximum level value on the plus side) − (amplitude maximum level value on the minus side)} ± α2 (where α2 ≧ 0), depending on whether the calculated value G is G ≦ 0 or G ≧ 0 Switch over. For example, FIG. 11 is a waveform diagram for explaining the calculated value G, and in this case, the calculated value G = (β1 + β
2) / (β1-β2).

[(Amplitude maximum level value on the plus side) + (Amplitude maximum level value on the minus side)} / {(Amplitude on the plus side) Maximum level value) − (amplitude maximum level value on the minus side)}, the calculated value H is H ≧ 0
Or H ≦ 0 is switched. For example, FIG. 11 is a waveform diagram for explaining the calculated value H, and in this case, the calculated value H = (β1S + β2S) / (β1
S-β2S).

A from the recording medium on which the mark length is recorded
The C-coupled reproduction signal is switched between the case where the polarity is not changed to the input signal A and the case where the polarity is inverted to become the input signal A, and the maximum value of the slice offset signal S5 is ≧ 0.
Is selected (in the case of AX-BX-CA-DA) or the maximum value is ≦ 0 (in the case of AX-BX-CB-DB) as the input signal A.

This is because the vicinity where the value defined by is zero is considered to be the recording state (near the optimum recording power) where the minimum jitter value is obtained. Since the jitter shows a minimum value when the slice level value is set near the amplitude center of the shortest mark, from the definition of H, H = 0 is guaranteed to be near the jitter minimum value. On the other hand, from the amplitude of the long mark (longest mark), the deviation of the recording power from the minimum jitter value (whether the deviation is toward the low recording power side,
F, G trying to know if it is deviated to the high recording power side)
Is a very easy method in terms of sampling, but since it is a method of indirectly evaluating the state of short marks, offset may occur.

Therefore, by introducing the offsets ± α1 and ± α2, it is guaranteed that F = 0 or G = 0 is near the recording power at which the jitter minimum value is reached. The polarity of the input signal S1 is switched by the positive / negative judgment of F, G, H, but the direction of the inequality sign of F, G, H is (whether ≦ or ≧).
It depends on the polarity of the signal from the recording medium. That is,
In the case of a recording medium in which the output signal is lower than that of the unrecorded portion, F ≧ 0, G ≦ 0, and H ≧ 0 are recorded at a low recording power with respect to the recording power at which the jitter minimum value is obtained. The opposite state is the state in which the recording is performed with a high recording power with respect to the recording power with the minimum jitter value. On the other hand, in the case of a recording medium in which the output signal increases with respect to the unrecorded portion, F ≦ 0, G ≧ 0, and H ≦ 0 are low recording powers with respect to the recording power at which the jitter minimum value is obtained. The recording state is the recording state, and the opposite is the recording state with a high recording power with respect to the recording power at which the jitter minimum value is obtained.

On the other hand, in the method 1, the AC-coupled reproduction signal from the recording medium on which the mark length is recorded is used as the input signal S1 of the comparator 1 without changing the polarity and the polarity is inverted. It is to determine which is the region where the error rate can be suppressed, and the switching determination of the input signal S1 of the comparator 1 is a theoretically clear method (F,
In the judgment by G, the values of the offsets ± α1 and ± α2 cannot be theoretically obtained, and may change under recording conditions such as the recording linear velocity).

In the case of the combination of AX-BX-CA-DA, the shift of the slice level value (shift direction of the slice level value C) due to the high level output attenuation of the comparator 1 occurs in the positive direction, so that the error rate is reduced. To achieve this, the entire slice level value (slice level value viewed macroscopically) may be set to the plus side of the input signal S1 of the comparator 1, which means that the voltage of the slice offset signal S5 is ≧ 0. Is to become. That is, the fact that the voltage of the slice offset signal S5 is ≧ 0 guarantees that the reduction of the error rate based on the high level output attenuation of the comparator 1 is effective.

When the voltage of the slice offset signal S5 is ≤0 in the initial polarity of the input signal S1, the voltage of the slice offset signal S5 is ≥0 by inverting the polarity of the input signal S1. It is guaranteed that the error rate reduction based on the high level output attenuation property of 1 is effective. On the other hand, in the case of the combination of AX-BX-CB-DB, the shift of the slice level value (shift direction of the slice level value C) due to the high level output attenuation of the comparator 1 occurs in the negative direction, so that the error rate is reduced. To achieve this, the entire slice level value (slice level value viewed macroscopically) may be set to the minus side of the input signal of the comparator 1, which makes the voltage of the slice offset signal S5 ≦ 0. Is to be. That is, the fact that the voltage of the slice offset signal S5 becomes ≦ 0 guarantees that the reduction of the error rate based on the high level output attenuation of the comparator 1 is effective.

When the voltage of the slice offset signal S5 is ≧ 0 with the initial polarity of the input signal S1, the voltage of the slice offset signal S5 becomes ≦ 0 by inverting the polarity of the input signal S1. It is guaranteed that the error rate reduction based on the high level output attenuation property of 1 is effective. The determination based on the slice offset signal S5 can use any of the average value, the minimum value, and the maximum value of the slice offset signal S5. However, the maximum value of the slice offset signal S5 referred to here indicates an average level of the maximum value, and does not indicate a signal that is significantly larger than the others. Similarly, the minimum value of the slice offset signal S5 referred to here indicates an average level of the minimum value, and does not indicate a signal which is significantly smaller than the others.

Next, the operation confirmation in this auto slice circuit will be described. In the following description, unless otherwise specified, AA-BX (X is A or B) -CA-DA.
That is, from the recording medium, a signal such that the recording portion (mark portion) has a voltage lower than that of the unrecorded portion (space portion) is obtained, and the slice offset signal S5 is (DC offset signal S4)- (Integrated signal S3),
The comparator 1 compares the input signal (HF signal) S1 with the slice offset signal S5, and when the input signal> the slice offset signal, the output is a low level value (for example, 0).
(V)), when the input signal is smaller than the slice offset signal, a case where the comparator output signal S2 whose output becomes a high level value (for example, +5 (V)) is output will be described. However, the comparator output signal S2 of the comparator 10 is
As shown in FIG. 4, the high level value is configured to decrease (decrease) with the output time.

(Confirmation 1 of Operation of Auto Slice Circuit) FIGS. 12 to 18 are diagrams showing signal waveforms at the time of confirming the operation of the auto slice circuit shown in FIG. Wavelength 66
Using a 0 nm, NA 0.65 optical pickup, a 14T single pattern was recorded on a commercially available DVD-R disc by changing the recording clock frequency.
Playback was performed with an optical pickup of 50 nm and NA of 0.60, and the operation of this auto slice circuit was examined. Note that here, BX is BA (the polarity inversion signal of the signal from the recording medium is the input signal (HF signal) S1 of the comparator 1).
And).

Input signal S1 input to comparator 1
Then, the slice offset signal S5 fed back to the comparator 1 and further the comparator output signal S2 were examined. As a result, as shown in FIGS. 12 to 18, when the frequency of the input signal S1 is high (see, for example, FIG.
2 to FIG. 15), the comparator output signal S is almost equal to
2 has a high level time TH and a low level time TL due to a decrease in the frequency of the input signal S1 (see, for example, FIGS.
8) It was confirmed that TH> TL. As shown in FIGS. 12 to 18, this is because the high-level voltage of the comparator output signal S2 gradually decreases due to the decrease in the frequency of the input signal S1, and the voltage value of the slice offset signal S5 fed back to the comparator 1 is set. It can be seen that this is due to the rise.

FIG. 19 is a diagram showing the relationship between the frequency of the input signal S1 and the voltage value of the slice offset signal S5 fed back to the comparator 1. FIG. 20 shows the input signal S
It is a diagram which shows the relationship of the frequency of 1 and the high level time and low level time of the final binary signal. As shown in FIG. 19, the result is that the voltage value of the slice offset signal S5 fed back to the comparator 1 increases due to the decrease in the frequency of the input signal S1, and as described with reference to FIG. 11, within the range of a certain recording state. It can be confirmed that the deterioration of the error rate can be suppressed by. The final binarized signal (a signal obtained by binarizing the reproduced signal from the recording medium) becomes the comparator output signal S2.

Then, when the frequency of the input signal S1 and the relationship between the high level time (corresponding to the space length) and the low level time (corresponding to the mark length) of the final binarized signal are measured, the result is shown in FIG. As shown in FIG. 20, the high level time (space length) and the low level time (mark length), which are almost equal when the frequency of the input signal is high, are reduced by the decrease of the frequency of the input signal S1 (for example, the frequency of the input signal). Was confirmed to be 40 (MHz or less)) space length> mark length. The tendency is exactly the same as the results of FIGS. 12 to 19, and it was confirmed that the portion recorded with the recording power higher than the optimum recording power can be reproduced while suppressing the deterioration of the error rate (the reason is , [Means for Solving the Invention].

(Confirmation 2 of Operation of Auto Slice Circuit) FIG. 21 is a diagram showing the relationship between the jitter and the error rate in the auto slice circuit shown in FIG. Wavelength 6
Using an optical pickup of 60 nm and NA of 0.65, a random pattern was recorded on a commercially available DVD-R disc while changing the recording power, and the jitter (σ / Tw) was measured. Here, BX is BA (the polarity inversion signal of the signal from the recording medium is the input signal (HF signal) S1 of the comparator 1). Further, the portion recorded as described above was reproduced by an optical pickup having a wavelength of 650 nm and NA of 0.60, and the jitter (σ / Tw) and the error rate (average PI error number of 8 ECC blocks) were measured. As a result, as shown in FIG. 21, the error rate becomes extremely small in the area recorded on the recording power side higher than the recording power at which the jitter becomes the minimum value, and the error rate also increases as the recording power increases. It was confirmed that it did not increase.

(Confirmation 3 of the reproducing apparatus operation of the present invention) FIG.
FIG. 23 is a diagram showing the relationship between the error rate and G in the auto slice circuit shown in FIG. 1, and FIG. 23 is a diagram showing the relationship between the error rate and the average voltage of the slice offset signal.
FIG. 24 is a diagram showing a relationship between another jitter and an error rate in the auto slice circuit shown in FIG. Similarly to the above, an optical pickup having a wavelength of 660 nm and an NA of 0.65 was used to record a random pattern on a commercially available DVD-R disc while changing the recording power. At that time, BX to B
Jitter (σ / T) when A is set (the polarity inversion signal of the signal from the recording medium is set as the input signal S1 of the comparator 1)
w) is as shown in FIG. 21, and the optimum recording power is about 14.0 (mw), and it is confirmed that if the recording power is deviated from the optimum recording power, the jitter is significantly deteriorated. It was

Next, for the portion recorded by changing the recording power, the error rate and G (= β + 0) when BX is set to BA (the polarity inversion signal of the signal from the recording medium is used as the input signal of the comparator) 1) and the relationship between the error rate and the average voltage of the slice offset signal were investigated. The results are shown in FIGS. 22 and 23. From this result, in the region where G = (β + 0.1) ≧ 0 or the maximum value of the slice offset signal S5 is 0 (V) or more, when BX is set to BA, the error rate can be reduced. It turns out that there is a guarantee.

Then, when G = (β + 0.1) ≦ 0, or when the maximum value of the slice offset signal S5 becomes ≦ 0 (V), BX is switched from BA to BB. The result is as shown in FIG. 24 (however, the recording power side higher than about 14.0 mw is the value when BX is BA), and recording is performed by switching BX by G or the slice offset signal. It was confirmed that the information could be reproduced with a low error rate even if the recording was not performed with the optimum recording power.

In this way, the effectiveness of the method of switching the polarity of the input signal (switching BX) by the G or slice offset signal could be confirmed. In addition,
Since F and H have almost the same curve as G, the effect is exactly the same (F, G, and H are different only in the measuring method and the expressing method). In the above, the operation of the reproducing apparatus of the present invention and the effectiveness thereof have been shown in the case of AA-BX-CA-DA, but in other cases, the polarity of determination is different and the operation is exactly the same. is there.

In this way, the auto slice circuit of this embodiment, whether recording is performed with a recording power lower than the optimum recording power or conversely with a high recording power,
Even if the amount of deviation from the optimum recording power is large to some extent, information can be reproduced with low jitter and a low error rate, and the reliability of reproduction can be greatly improved. Also, due to the improvement in the reliability of reproduction, it becomes possible to greatly relax the recording condition at the time of recording (that is, the allowable range of the setting condition at the time of recording can be increased).
The load on the recording device can be reduced. Further, since the configuration is almost the same as that of the conventional auto slice circuit, the productivity is also excellent.

[0110]

As described above, according to the information reproducing apparatus of the present invention, even if the recording apparatus does not select the optimum recording condition such as the recording power, the information reproducing apparatus can reproduce the information with a low error rate. The device can be realized, and the load and cost of the recording device can be reduced.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an auto slice circuit which is an embodiment of an information reproducing apparatus of the present invention.

2 is a list of combinations of states of signals and the like according to each claim of the present invention of the auto slice circuit shown in FIG.

FIG. 3 is a waveform diagram showing signals of respective parts in the auto slice circuit shown in FIG.

FIG. 4 is a waveform diagram of a comparator output signal output from the comparator 1 shown in FIG.

FIG. 5 is a diagram schematically showing an eye pattern of a portion recorded with a recording power slightly lower than the optimum recording power.

FIG. 6 is a diagram schematically showing an eye pattern of a portion recorded with an optimum recording power.

FIG. 7 is a diagram schematically showing an eye pattern of a portion recorded with a recording power slightly higher than the optimum recording power.

8 is an explanatory diagram of a slice level shift direction due to the attenuation of the high level output voltage of the comparator 1 shown in FIG.

9 is an explanatory diagram of a slice level shift direction due to the attenuating property of the high level output voltage of the comparator 1 shown in FIG.

10 is a waveform diagram for explaining a calculation value F in the auto slice circuit shown in FIG.

11 is a waveform diagram for explaining a calculated value G in the auto slice circuit shown in FIG.

FIG. 12 is a diagram showing a signal waveform when the operation of the auto slice circuit shown in FIG. 1 is confirmed.

13 is a diagram showing a signal waveform when the operation of the auto slice circuit shown in FIG. 1 is confirmed.

FIG. 14 is a diagram showing a signal waveform when the operation of the auto slice circuit shown in FIG. 1 is confirmed.

15 is a diagram showing a signal waveform when the operation of the auto slice circuit shown in FIG. 1 is confirmed.

16 is a diagram showing a signal waveform when the operation of the auto slice circuit shown in FIG. 1 is confirmed.

17 is a diagram showing a signal waveform when the operation of the auto slice circuit shown in FIG. 1 is confirmed.

18 is a diagram showing a signal waveform when the operation of the auto slice circuit shown in FIG. 1 is confirmed.

19 is a diagram showing the relationship between the frequency of the input signal S1 shown in FIG. 1 and the voltage value of the slice offset signal S5 fed back to the comparator 1. FIG.

20 is a diagram showing the relationship between the frequency of the input signal S1 shown in FIG. 1 and the high level time and low level time of the final binarized signal.

21 is a diagram showing the relationship between jitter and error rate in the auto slice circuit shown in FIG. 1. FIG.

22 is a diagram showing a relationship between an error rate and G in the auto slice circuit shown in FIG.

23 is a diagram showing the relationship between the error rate shown in FIG. 1 and the average voltage of the slice offset signal.

FIG. 24 is a diagram showing a relationship between another jitter and an error rate in the auto slice circuit shown in FIG.

FIG. 25 is a circuit diagram showing a configuration of a conventional auto slice circuit.

FIG. 26 is a waveform diagram showing output signals of respective parts of the auto slice circuit shown in FIG.

[Explanation of symbols]

1,11: Comparator 2, 12: Integrator circuit 3:13: Subtraction circuit

Claims (16)

[Claims] 1. An information reproducing apparatus for discriminating the original information from a reproduced signal of a recording medium in which a mark length is recorded and a recorded portion has an output signal lower than that of an unrecorded portion and reproducing the original information. A comparator which outputs a low level signal when the level value is higher than a predetermined level value of 1, and a high level signal which decreases when the output level is lower than the first predetermined level value as the output time increases. A difference means between the second predetermined level value and the direct current component value obtained by the integration processing by the integration means. , An auto-slicing means configured to return the difference signal to the comparing means, the auto-slicing means supplying the difference signal returning to the comparing means (the first Of the predetermined level value)-(the DC component value), and the calculated value of (shortest mark amplitude center level value)-(longest mark amplitude center level value) -offset value α1 (where α1 ≧ 0) in the reproduction signal is 0. In the above case, a signal obtained by AC coupling the reproduction signal is selected as the input signal. When the calculated value is not 0 or more, the reproduction inversion signal obtained by AC coupling the reproduction signal and inverting the polarity is used as the input signal. An information reproducing apparatus characterized in that it is selected and input is switched respectively. 2. An information reproducing apparatus for recording the mark length and discriminating the original information from the reproduction signal of the recording medium such that the output signal of the recording section is lower than that of the unrecorded section, and reproducing the original information. A comparator which outputs a low level signal when the level value is higher than a predetermined level value of 1, and a high level signal which decreases when the output level is lower than the first predetermined level value as the output time increases. A difference means between the second predetermined level value and the direct current component value obtained by the integration processing by the integration means. , An auto-slicing means configured to return the difference signal to the comparing means, the auto-slicing means supplying the difference signal returning to the comparing means (the first Of the predetermined level value)-(the DC component value) and {(plus side amplitude maximum level value) + (minus side amplitude maximum level value)} / {(plus side If the calculated value of (amplitude maximum level value)-(minus side amplitude maximum level value)} + offset value α2 (where α2 ≧ 0) is 0 or less, a signal obtained by AC coupling the reproduction signal is selected as the input signal. When the calculated value is not 0 or less, the reproduction signal is AC-coupled and the reproduction inversion signal in which the polarity is inverted is selected as the input signal, and the input signal is switched and input. 3. An information reproducing apparatus for discriminating and reproducing original information from a reproduced signal of a recording medium in which a mark length is recorded and a recorded portion has an output signal lower than that of an unrecorded portion. A comparator which outputs a low level signal when the level value is higher than a predetermined level value of 1, and a high level signal which decreases when the output level is lower than the first predetermined level value as the output time increases. A difference means between the second predetermined level value and the direct current component value obtained by the integration processing by the integration means. , An auto-slicing means configured to return the difference signal to the comparing means, the auto-slicing means supplying the difference signal returning to the comparing means (the first Predetermined level value) of - (the the DC component value), the maximum amplitude level value of {(the positive side of the shortest mark in a signal of the reproduced signal AC-coupled) +
When the calculated value of ((minus side amplitude maximum level value)) / {(plus side amplitude maximum level value)-(minus side amplitude maximum level value)} is 0 or more, the reproduction signal is AC.
The combined signal is selected as the input signal, and when the calculated value is not 0 or more, the reproduction inversion signal in which the reproduction signal is AC-coupled and the polarity is inverted is selected as the input signal and each of them is switched and input. An information reproducing apparatus characterized by the above. 4. An information reproducing apparatus for reproducing original information by discriminating original information from a reproduced signal of a recording medium in which a mark length is recorded and a recorded portion has an output signal lower than that of an unrecorded portion. A comparator which outputs a low level signal when the level value is higher than a predetermined level value of 1, and a high level signal which decreases when the output level is lower than the first predetermined level value as the output time increases. A difference means between the second predetermined level value and the direct current component value obtained by the integration processing by the integration means. , An auto-slicing means configured to return the difference signal to the comparing means, the auto-slicing means supplying the difference signal returning to the comparing means (the first Of the predetermined level value)-(the direct current component value), and the reproduction signal is AC-coupled and the polarity is not changed, or the reproduction signal is AC-coupled and the polarity is inverted. An information reproducing apparatus characterized in that (the second predetermined level value)-(the direct current component value) which is 0 or more is selected and inputted as the input signal. 5. An information reproducing apparatus for reproducing original information from a reproduced signal of a recording medium in which a mark length is recorded and a recorded portion has an output signal increased with respect to an unrecorded portion. A comparator which outputs a low level signal when the level value is higher than a predetermined level value of 1, and a high level signal which decreases when the output level is lower than the first predetermined level value as the output time increases. A rate difference means and an integrator means for integrating the output signal outputted by the comparator means are provided, and a difference signal E between the second predetermined level value and the DC component value obtained by the integration processing by the integration means is provided. The auto slicing means is configured to return the difference signal to the comparator means, and the auto slicing means returns the difference signal to the comparator means (the above-mentioned 2 (predetermined level value) − (the DC component value), and the calculated value of (shortest mark amplitude center level value) − (longest mark amplitude center level value) + offset value α1 (where α1 ≧ 0) in the reproduction signal When it is 0 or less, a reproduction inversion signal obtained by AC coupling the reproduction signal and inverting the polarity is selected as the input signal, and the calculated value is 0.
In the case where the following is not true, an information reproducing apparatus characterized in that a signal obtained by AC-coupling the reproduced signal is selected as the input signal and each of them is switched and input. 6. An information reproducing apparatus for reproducing original information from a reproduced signal of a recording medium in which a mark length is recorded and a recorded portion has an output signal increased with respect to an unrecorded portion. A comparator which outputs a low level signal when the level value is higher than a predetermined level value of 1, and a high level signal which decreases when the output level is lower than the first predetermined level value as the output time increases. A rate difference means and an integrator means for integrating the output signal outputted by the comparator means are provided, and a difference signal E between the second predetermined level value and the DC component value obtained by the integration processing by the integration means is provided. The auto slicing means is configured to return the difference signal to the comparator means, and the auto slicing means returns the difference signal to the comparator means (the above-mentioned 2 (predetermined level value) − (the DC component value), and {(plus side amplitude maximum level value) + (minus side amplitude maximum level value)} / {(plus side in the signal obtained by AC coupling the reproduction signal Amplitude maximum level value)-(minus side amplitude maximum level value)}-offset value α2 (where α2 ≧ 0) when the calculated value is 0 or more, the reproduction signal is AC-coupled and the polarity is inverted. A signal is selected as the input signal, and when the calculated value is not 0 or more, a signal obtained by AC-coupling the reproduction signal is selected as the input signal A, and each of them is switched and input. apparatus. 7. An information reproducing apparatus which records original mark information and reproduces it by discriminating the original information from the reproduced signal of the recording medium such that the output signal increases with respect to the unrecorded portion in the recorded portion. A comparator which outputs a low level signal when the level value is higher than a predetermined level value of 1, and a high level signal which decreases when the output level is lower than the first predetermined level value as the output time increases. A difference means between the second predetermined level value and the direct current component value obtained by the integration processing by the integration means. , An auto-slicing means configured to return the difference signal to the comparing means, the auto-slicing means supplying the difference signal returning to the comparing means (the first Predetermined level value) of - (the the DC component value), the maximum amplitude level value of {(the positive side of the shortest mark in a signal of the reproduced signal AC-coupled) +
When the calculated value of ((minus side amplitude maximum level value)) / {(plus side amplitude maximum level value)-(minus side amplitude maximum level value) is 0 or less, the reproduced signal is AC.
A reproduction inversion signal that is coupled and inverted in polarity is selected as the input signal, and if the calculated value is not 0 or less, a signal obtained by AC coupling the reproduction signal is selected as the input signal and each is input for switching. An information reproducing apparatus characterized by the above. 8. An information reproducing apparatus for reproducing original information by discriminating original information from a reproduced signal of a recording medium in which a mark length is recorded and a recorded portion has an output signal increased with respect to an unrecorded portion. A comparator which outputs a low level signal when the level value is higher than a predetermined level value of 1, and a high level signal which decreases when the output level is lower than the first predetermined level value as the output time increases. A difference means between the second predetermined level value and the direct current component value obtained by the integration processing by the integration means. , An auto-slicing means configured to return the difference signal to the comparing means, the auto-slicing means supplying the difference signal returning to the comparing means (the first Of the predetermined level value)-(the direct current component value), and the reproduction signal is AC-coupled and the polarity is not changed, or the reproduction signal is AC-coupled and the polarity is inverted. An information reproducing apparatus characterized in that (the second predetermined level value)-(the direct current component value) which is 0 or more is selected and inputted as the input signal. 9. An information reproducing apparatus for reproducing original information by discriminating original information from a reproduced signal of a recording medium in which a mark length is recorded and a recorded portion has an output signal lower than that of an unrecorded portion. A comparator which outputs a low level signal when the level value is lower than a predetermined level value of 1, and a high level signal which decreases when the output level is higher than the first predetermined level value as the output time increases. A difference means between the second predetermined level value and the direct current component value obtained by the integration processing by the integration means. , An auto-slicing means configured to return the difference signal to the comparator means, the auto-slicing means including the difference signal (the direct signal) being returned to the comparator means. Component value)-(the second predetermined level value), and the calculated value of (shortest mark amplitude center level value)-(longest mark amplitude center level value) -offset value α1 (where α1 ≧ 0) in the reproduction signal is obtained. When it is 0 or more, a reproduction inversion signal obtained by AC coupling the reproduction signal and inverting the polarity is selected as the input signal, and the calculated value is 0.
If not, the information reproducing apparatus is characterized in that a signal obtained by AC-coupling the reproduced signal is selected as the input signal and is switched and input. 10. An information reproducing apparatus which records original mark information and reproduces it by discriminating original information from a reproduced signal of a recording medium in which a recorded portion has an output signal lower than that of an unrecorded portion. A comparator which outputs a low level signal when the level value is lower than a predetermined level value of 1, and a high level signal which decreases when the output level is higher than the first predetermined level value as the output time increases. A difference means between the second predetermined level value and the direct current component value obtained by the integration processing by the integration means. , Auto-slicing means configured to return the difference signal to the comparing means, wherein the auto-slicing means returns the difference signal to the comparing means (the Flow component value) − (the second predetermined level value), and {(plus amplitude maximum level value on the plus side) + (minus amplitude maximum level value)} / {(plus on the signal obtained by AC coupling the reproduction signal). Side amplitude maximum level value)-(minus side amplitude maximum level value)} + offset value α2 (where α2 ≧ 0) when the calculated value is 0 or less, the reproduction signal is AC-coupled to reproduce the polarity inverted. Information reproduction, characterized in that an inverted signal is selected as the input signal, and when the calculated value is not 0 or less, a signal obtained by AC coupling the reproduction signal is selected as the input signal and each of them is switched and input. apparatus. 11. An information reproducing apparatus which records original mark information and reproduces it by discriminating original information from a reproduced signal of a recording medium in which a recorded portion has an output signal lower than that of an unrecorded portion. A comparator which outputs a low level signal when the level value is lower than a predetermined level value of 1, and a high level signal which decreases when the output level is higher than the first predetermined level value as the output time increases. A difference means between the second predetermined level value and the direct current component value obtained by the integration processing by the integration means. , Auto-slicing means configured to return the difference signal to the comparing means, wherein the auto-slicing means returns the difference signal to the comparing means (the Flow component values) - (the second and the predetermined level value), the maximum amplitude level value of {(the plus side shortest mark in a signal of the reproduced signal AC-coupled) +
When the calculated value of ((minus side amplitude maximum level value)) / {(plus side amplitude maximum level value)-(minus side amplitude maximum level value)} is 0 or more, the reproduction signal is AC.
A reproduction inversion signal that is coupled and inverted in polarity is selected as the input signal, and if the calculated value is not 0 or more, a signal obtained by AC coupling the reproduction signal is selected as the input signal and each is input for switching. An information reproducing apparatus characterized by the above. 12. An information reproducing apparatus for reproducing original information by discriminating original information from a reproduced signal of a recording medium in which a mark length is recorded and a recorded portion has an output signal lower than that of an unrecorded portion. A comparator which outputs a low level signal when the level value is lower than a predetermined level value of 1, and a high level signal which decreases when the output level is higher than the first predetermined level value as the output time increases. A difference means between the second predetermined level value and the direct current component value obtained by the integration processing by the integration means. , Auto-slicing means configured to return the difference signal to the comparing means, wherein the auto-slicing means returns the difference signal to the comparing means (the Flow component value)-(the second predetermined level value), and the reproduction signal is AC-coupled and the polarity is not changed, or the reproduction signal is AC-coupled and the polarity is inverted. (The DC component value) −
An information reproducing apparatus characterized in that the one having the (second predetermined level value) of 0 or less is selected and inputted as the input signal. 13. An information reproducing apparatus for recording the mark length, wherein the recording section discriminates the original information from the reproduction signal of the recording medium such that the output signal increases with respect to the unrecorded section, and reproduces the original information. A comparator which outputs a low level signal when the level value is lower than a predetermined level value of 1, and a high level signal which decreases when the output level is higher than the first predetermined level value as the output time increases. A difference means between the second predetermined level value and the direct current component value obtained by the integration processing by the integration means. , Auto-slicing means configured to return the difference signal to the comparing means, wherein the auto-slicing means returns the difference signal to the comparing means (the Flow component value)-(the second predetermined level value), and the calculated value of (shortest mark amplitude center level value)-(longest mark amplitude center level value) + offset value α1 (where α1 ≧ 0) in the reproduction signal. Is 0 or less, a signal obtained by AC coupling the reproduction signal is selected as the input signal, and when the calculated value is not 0 or less, the reproduction inversion signal obtained by AC coupling the reproduction signal and inverting the polarity is input to the input. An information reproducing apparatus characterized in that it is selected as a signal and is switched and inputted respectively. 14. An information reproducing apparatus for reproducing original information by discriminating original information from a reproduced signal of a recording medium in which a mark length is recorded and a recorded portion has an output signal increased with respect to an unrecorded portion. A comparator which outputs a low level signal when the level value is lower than a predetermined level value of 1, and a high level signal which decreases when the output level is higher than the first predetermined level value as the output time increases. A difference means between the second predetermined level value and the direct current component value obtained by the integration processing by the integration means. , Auto-slicing means configured to return the difference signal to the comparing means, wherein the auto-slicing means returns the difference signal to the comparing means (the Flow component value) − (the second predetermined level value), and {(plus amplitude maximum level value on the plus side) + (minus amplitude maximum level value)} / {(plus on the signal obtained by AC coupling the reproduction signal). Side amplitude maximum level value)-(minus side amplitude maximum level value)}-offset value α2 (where α2 ≧ 0) when the calculated value is 0 or more, a signal obtained by AC coupling the reproduction signal is used as the input signal. When the calculated value is not equal to or more than 0, the reproduced signal is AC-coupled and the reproduced inverted signal in which the polarity is inverted is selected as the input signal, and the input signal is switched and input. apparatus. 15. An information reproducing apparatus for reproducing original information by discriminating original information from a reproduced signal of a recording medium in which a mark length is recorded and a recorded portion has an output signal increased with respect to an unrecorded portion. A comparator which outputs a low level signal when the level value is lower than a predetermined level value of 1, and a high level signal which decreases when the output level is higher than the first predetermined level value as the output time increases. A difference means between the second predetermined level value and the direct current component value obtained by the integration processing by the integration means. , Auto-slicing means configured to return the difference signal to the comparing means, wherein the auto-slicing means returns the difference signal to the comparing means (the Flow component values) - (the second and the predetermined level value), the maximum amplitude level value of {(the plus side shortest mark in a signal of the reproduced signal AC-coupled) +
When the calculated value of ((minus side amplitude maximum level value)) / {(plus side amplitude maximum level value)-(minus side amplitude maximum level value) is 0 or less, the reproduced signal is AC.
A combined signal is selected as the input signal, and when the calculated value is not 0 or less, the reproduction inversion signal in which the reproduction signal is AC-coupled and the polarity is inverted is selected as the input signal and each of them is switched and input. An information reproducing apparatus characterized by the above. 16. An information reproducing apparatus for reproducing original information by discriminating original information from a reproduced signal of a recording medium in which a mark length is recorded and a recorded portion has an output signal increased with respect to an unrecorded portion. A comparator which outputs a low level signal when the level value is lower than a predetermined level value of 1, and a high level signal which decreases when the output level is higher than the first predetermined level value as the output time increases. A difference means between the second predetermined level value and the direct current component value obtained by the integration processing by the integration means. , Auto-slicing means configured to return the difference signal to the comparing means, wherein the auto-slicing means returns the difference signal to the comparing means (the Flow component value)-(the second predetermined level value), and the reproduction signal is AC-coupled and the polarity is not changed, or the reproduction signal is AC-coupled and the polarity is inverted. Of (the aforementioned DC component value)
An information reproducing apparatus characterized in that the one in which (the second predetermined level value) becomes 0 or less is selected and input as the input signal.