JPS61214278A - Information reproducing system - Google Patents

Abstract

PURPOSE:To attain reproduction being not influenced by the relative relation change between a reading signal and the threshold value of a digital ratio by detecting signals corresponding to a front and a rear edges of a recording information respectively individually and carrying out a reproduction of a timing signal and a data reproduction by the timing signal respectively individually. CONSTITUTION:Outputs of a rise and a fall edge detecting circuits 20, 30 respectively reproduce a continuous clock corresponding to a rise and a fall of a binary pulse. A detecting circuit 22 decides a data pulse corresponding to a rise edge by the clock formed from the rise edge pulse reproduced by a PLL circuit 21. A detecting circuit 32 carries out a similar processing on the fall edge by the reproducing clock of a PLL circuit 31. A circuit 40 synthesizes processing results of two edge pulses and a decoder 50 demodulates a data from this data system. In such a manner, the front and the rear edges are not influenced by a change of the relative relation between the reading signal and the threshold value of the digital ratio by the respective and individual processing of the corresponding signal, the data can be reproduced.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to an information recording/reproducing device such as an optical disk, and particularly an information recording/reproducing method suitable for high density [Background of the Invention] Information recording using light, magnetism, etc. As a method for recording and reproducing information on a medium, conventional methods have been used to set an appropriate threshold value or detect a peak position in order to convert an analog signal from an information read head into a digital signal such as binarization. . In an information recording/reproducing apparatus using a recording/reproducing principle such as an optical disk, information is recorded by partially changing the optical or magnetic properties of the medium. For example, Philips Technical Rev & - (Ph1l 1ps
technical review) Vol 40
, 1982° No. 6 p157-p164. The regeneration process will be explained with reference to FIG. (1
) indicates information recorded on track l. (b) is an analog signal from the read head moving along the track.

A binarized signal as shown in (c) is obtained using an appropriate threshold value 4, and this is processed to reproduce the information. By the way, the analog signal (b) varies greatly in amplitude, shape, etc. depending on the recording and reproduction conditions. Therefore, if the threshold value 4 is fixed, it will greatly affect the shape of the binarized signal (/→.On the other hand, it is very difficult to change the value between them quickly according to the above fluctuations, and therefore the relative change in the threshold value However, the use is limited to a range where the influence of the noise is negligible.Therefore, there was a problem in that high-density information recording and reproduction was difficult.

[Purpose of the invention]

An object of the present invention is to provide an information recording and reproducing method that does not affect the reproduction of information even if the relative relationship between a read analog signal and a threshold value for converting it into a digital signal by binarizing or multilayering it changes. Our goal is to provide the following.

[Summary of the invention]

The principle of the present invention is that when the analog signal waveform shown in FIG. 1 (b) is examined only its rising and falling parts,
It is based on the fact that they can be expressed in the same form (function).

In other words, the relationship between the threshold value for digitization and the digitized signal reflects the functional form of the waveform, and is therefore regular.Using this fact, it is possible to generate signals corresponding to the leading and trailing edges of recorded information. The present invention is characterized in that each of these signals is detected independently, and a timing signal is independently reproduced from each of these signals, and data is reproduced using the timing signal.

[Embodiments of the invention]

The present invention will be explained in detail below with reference to Examples. FIG. 2 shows a first embodiment of the present invention. FIG. 2 shows a block diagram of a data reproducing circuit implementing the present invention. Reference numeral 10 denotes a read head which outputs an analog signal waveform 3 as shown in FIG. 3(A) according to recorded information on the medium (for example, pits recorded on an optical disk). 11 is a binarization circuit that converts the threshold value 4 and analog waveform 3 shown in Fig. 3 (a) into Fig. 3 (b).
A binarized pulse 5 shown in is output. 20 is a pulse 5-1 corresponding to the rising portion of the binarized pulse 5 (Fig. 3 (c)
), and 30 is a circuit that takes out the pulse 5-2 (shown in FIG. 3) corresponding to the falling portion of the binarized pulse 5. In FIG. 3, 5-1 is a pulse corresponding to the rising edge of the binarized pulse 5, and 5-2 is a pulse corresponding to the falling edge, which will be referred to as edge pulses or data pulses. 21 and 31 are timing regeneration circuits, for example, P L L (Phase L
(locked Loop) circuit.

That is, the outputs of the rising edge detection circuit 2 (l) and the falling edge detection circuit 30 are reproduced as continuous clocks corresponding to the rising timing and falling timing of the binarized pulse 5, respectively. 22 and 32 are data detection circuits. So, P.L.
The presence or absence of a data pulse is determined at each timing of the clock reproduced by the L circuit 21.31. In other words, in the circuit 22, the clock is generated from the rising edge pulse.
Determine the data pulse corresponding to the rising edge.

Circuit 32 performs similar processing for falling edges.

40 is a circuit for synthesizing the processing results of the two edge pulses. This is simply captured with each clock signal,
The output may be a register that can be taken out using one of the above clocks or a third clock. 50 is a decoder that demodulates data from the above data series, and this is not necessarily unique to the present invention. In other words, the same decoder as the conventional device may be used. Specifics of the processing circuit for the above rising edge pulse 5-1 or falling edge pulse 5-2
An example is shown in FIG. 12 is a gate with two positive and two complementary outputs;
22.23 is a flip-flop 42 is an or gate, 41
is a register, and 43 is a clock signal. According to the embodiment shown in FIG. 2 described above, since the rising and falling edge pulses are processed separately, even if the relative relationship between the readout analog signal and the binarization threshold changes, the state of change in each edge pulse remains unchanged. Since continuous recorded information can be considered to be the same, data can be reproduced without being affected by the above fluctuations.

A second embodiment of the invention is shown in FIG. This embodiment differs from the embodiment shown in FIG. 2 in that a data decoder is provided independently for each of the rising edge and the falling edge. That is, in FIG. 5, 51 and 52 are decoders, respectively. The other parts are the same as in the case of FIG. A feature of this embodiment is that since rising and falling edges are processed independently, each can be regarded as an independent data channel. In other words, this is equivalent to multiplexing a channel consisting of rising edges and a channel consisting of falling edges.

Therefore, these two channels can be used either independently or in conjunction.

Next, a third embodiment of the present invention will be described. This is the embodiment shown in FIG. 5, which takes advantage of the property that two independent channels can be obtained. Signals such as synchronization signals and various marks are recorded along with the data, and data reproduction processing is performed based on these signals. FIG. 6 is an explanatory diagram of an embodiment in which the present invention is applied to a synchronization signal reproduction process. Assume that synchronization information is recorded along track l as 2-1.2-2.2-3, . The signal to be read out is binarized, and from the rising edge of the binarized pulse shown in (0), the edge pulse train 5-11°5-12.・
. . , the edge pulse train 5-21.5-22. It is possible to obtain synchronizing signal pulses by considering each pulse train of 0 (c), ni) as one piece of synchronization information. In this case (ha), to)
Since synchronization information can be obtained from either of the above, the synchronization signal is isometrically written twice, and high reliability of the synchronization signal can be achieved. Note that although the detection signals from the pulse trains in (c) and 2) may include a certain time difference, certain recorded information, such as the edge pulse from 2-1, the relationship between 5-11 and 5-21 may be disturbed. Because it never happens.

No contradiction will occur due to the above-mentioned time difference.

In addition, in the pattern (a) of Figure 6, 2-1.2-2,...
If all of the . . . and . . . The specific circuit configuration of this embodiment may be the same as that shown in FIG. However, the decoders 51 and 52 are used as synchronization signal detection circuits. A specific example of the synchronization signal pattern and a specific example of the detection method are the same as in, for example, Japanese Patent Application No. 57-51229.

Next, the fourth embodiment of the present invention will be described. As mentioned above, by treating rising edges and falling edges independently, each can be regarded as an independent data channel. Therefore, an information recording method that takes advantage of this property is described below. exists and vines. That is, to explain using the example of FIG. 6, the pulse train (/→to) is regarded as an independent data train. For example, 5-21 is the falling edge of recording information 2-1, and 5-12 is the falling edge of recording information 2-1. This is the rising edge of recorded information 2-2. Therefore, it is impossible for 5-12 to be earlier than 5-21.If the interval between the two becomes less than a certain value, it is no longer possible to extract them as two signals due to the resolution conditions of the read head. Therefore, the two channels are independent within the range that satisfies the resolution conditions of the read head. There are many solutions that satisfy this condition. For example, the above-mentioned patent application No. 57-51
It is also possible to use a code pattern of H.229 (normally modulated and recorded in a form called NRZ i).

Furthermore, the present invention can be applied to the detection of specific marks as shown in Japanese Patent Application No. 57-51230.

〔Effect of the invention〕

As explained above, according to the present invention, signals corresponding to the leading edge and trailing edge (rising edge, falling edge) of a read signal from information recorded on an information recording medium are extracted, and a self-clocking method (recorded data Since the above-mentioned two signals are processed independently in the data reproducing device using the method of regenerating the clock for reproduction from itself, the relative relationship between the read signal and the threshold value for digitization fluctuates. However, data can be played back without being affected by it.
A high-density data recording and reproducing system can be realized. Maintaining a constant relationship between the readout signal and the threshold value is an extremely difficult problem in devices such as optical disks where recording/reproducing conditions vary widely, and therefore the present invention cannot be applied to these devices. The effect of 0 is huge.
Furthermore, by processing the data as two independent data channels, it becomes possible to achieve high reliability of recorded information and to employ a unique modulation method.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the process of information reproduction, FIG. 2 is a block diagram showing the first embodiment of the present invention, FIG. 3 is an explanatory diagram showing the operation of FIG. 5 is a block diagram showing the second embodiment of the present invention, and FIG. 6 is an explanatory diagram showing the third embodiment of the present invention. lnidrack, 2: Recorded information, 3: Read analog waveform,
4: threshold value, 5: digitized output, 10: read head,
ii: Digitization circuit, 20°30 two-way detection circuit, 21, 31: PLL. 22.32: Data detection circuit, 40: Data synthesis circuit%
50, 51.52: Decoder. 7th eye 2nd eye 3rd eye

Claims (1)

[Claims] In an information reproduction method that reproduces data using signals from each edge of information recorded on a recording medium, signals corresponding to the leading and trailing edges of information recorded on the recorded information are detected and these signals are An information reproducing method characterized in that a timing signal is independently reproduced from each of the timing signals, and data is reproduced based on the timing signal.