JPS6396738A - Information reproducing method - Google Patents

Abstract

PURPOSE:To improve detecting accuracy for the start position of an information area, by outputting a prescribed signal at time of detecting an identification area, detecting a start bit by using an outputted signal, deciding the start posi tion of the information area, and reproducing information in the information area in order. CONSTITUTION:A binary-digitized signal at time of ON-track is represented as (a) in figure, and signals 21'-24', 30', and 31' correspond to a preamble area 21, the identification area 22, the information area 23, an end bit 24, the start bit 30, and an information part 30, respectively, and are the signals obtained from respective area. When a level of '1' within a gate shown as (c) in figure is detected, it is discriminated as the start bit, and the next bit can be discriminated as a bit representing the start of the information, and the information can be reproduced in order. In this way, since the information signal, and the signal which represents the start position of the information area pass the same system 112', and are inputted to an information fetch circuit 106', it is possible to make a delay circuit which matches the phases of both signals unnecessary, and to improve the accuracy to recognize the start position of the information area.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for reproducing information from an information recording carrier having a plurality of information tracks arranged.

[Prior Art] Conventionally, Q411! is used to record information using a light beam and to reproduce the recorded information using a light beam. Various body shapes are known, such as card, disk, and tape shapes. Among them,
Optical information recording carriers formed in the form of cards (hereinafter referred to as "optical cards") are expected to be in great demand as recording media that are easy to manufacture, highly portable, and have good accessibility.

An example of the recording format of such an optical card is shown in the schematic plan view of FIG.

In the figure, the optical cart 11- is provided with a recording area 2, and the recording area 2 is formed by arranging a plurality of hunts 3 in a plurality of rows. A large number of information tracks 4 are arranged in these hands 3, and each track 4 has an information amount of about several tens to 100 bits. Each track has a preamble area that creates a synchronization clock for information reproduction and separates the track from other tracks.1. It is composed of an identification area for identifying W, an information area in which information modulated by MFM modulation or the like is recorded, and an end bit area indicating the end of information.

Note that arrow A indicates the moving direction of the optical cart 1 during reproduction, and arrow C indicates the information reading scanning direction of the optical head during reproduction.

FIG. 6 shows a schematic configuration diagram of a device used for recording and reproducing the optical card as described above.

In the figure, an optical card 1 can be moved back and forth in the direction of the arrow by a rotation mechanism 6. Information recorded on the optical card 1 is read and reproduced track by track by the optical card 11. Light from a light source 7 such as an LED is focused by a lens system 8 and illuminates the optical card l. This track image of the optical card l is formed by an imaging optical system 9 onto a one-dimensional sensor array lO. Thus, an electrical signal corresponding to the information recorded on the track 4 is output from the sensor array IO.

The operation of reading the information track by the sensor array 10 will be described below.

Figure 7 shows the recording of the optical card l shown in Figure 5.
It is a partially enlarged schematic diagram. However, the shoulder line part in the figure shows a low reflectance part and represents information "1", and the blank part shows a high reflectance part and represents information "0".

In the figure, 12-a, 12-b, and 12-c are three information tracks that are continuous in the direction of the arrow on the optical card l, and 13 is an identification area.

The identification area specifies the minimum pit width in the optical cart 1.
In this case, it has hatched parts 17, 20 on both sides, IT blank parts 18, 19 from both sides toward the center, and a 4T hatched part 14 in the center. However, the hatched part 14 in the center is in the track alignment direction (toward direction).
or 1/2 the width of the information track (e.g. 12-a)
fQ approximately at the center of the width direction of the information track.
-It is placed.

FIGS. 8(a) and (b) show identification area 1 in FIG.
3 is a binary code written as a result of modulating the above-mentioned minimum bit width IT in correspondence with the minimum inversion interval of the signal. However, the 81st %1 (8'I) is the sensor array l
This is a binary code when the read position of O is on track, that is, corresponds to the position shown by the thick line 15, and FIG. 8(b) shows the read position of the sensor array IO or adjacent information. This is a binary code when the signal straddles tracks, for example, when it straddles information tracks 12-b and 12-c. As shown in the figure, when the reading position of the sensor array IO is at the position indicated by the thick line 15 in FIG. 7, the detected signal has a maximum inversion interval of 4T (FIG. ff58 (a)). Further, when the reading position t of the sensor array 10 is at the position indicated by the bold line 16, the detected signal has a maximum inversion interval of 6T (FIG. 8(b)).

However, when a signal having such inversion intervals of 4T and 6T is recorded in the information area using the MFM modulation method, for example, the information area has IT and 1.5T.

Since only a 2T width signal is obtained, it can be clearly distinguished from the signal in the information area.

Thus, by scanning the sensor array lO, the image shown in FIG.
) is detected, it is identified that the reading position of the sensor array 10 is on track, and after the signal pattern of FIG. 8(b) is detected, the signal pattern 8I3 is detected again.
If the signal pattern (a) is detected, the sensor array 10
It is possible to identify that the reading position of the track has been moved to a new track.

Further, the reading operation of the information track by the sensor array 10 is started by detecting the signal shown in FIG. 8(a).

(Dark Problems to be Solved by the Invention) FIG. 9 is a block diagram of a circuit for detecting the recording signal of the information track as described above.

As shown in the figure, the sensor array 10 is driven by a control signal 108 from the sensor array driver 101.

Then, from the sensor array 10, an analog waveform signal 107 corresponding to the image of the track on the optical card projected by the optical system enters the sensor array driver 101.
Furthermore, it enters the binarization circuit 102 as a signal 109. The signal 110 digitized by the circuit is sent to an identification area detection circuit 103, an information demodulation circuit 104 . The end bit detection circuit 105 is entered. The identification area detection circuit 103 detects the signals shown in FIGS. 8(a) and 8(b), and outputs a signal indicating the on-track state, a signal indicating moving to a new track, and a signal indicating the starting position of the information area. Ill is sent to the information acquisition circuit. The information demodulation circuit 104 demodulates the signal lt modulated by MFM modulation, for example, and sends it to the information acquisition circuit 106 as an information signal 112. The end bit circuit 105 detects the end bit and sends a signal indicating the end of the information and a signal 113 indicating moving to a new track to the information acquisition circuit 106. The information acquisition circuit 106 determines based on the signals 111, 112, and 113, and acquires a correct signal once from among the signals obtained by scanning the sensor array 10 or one track jIAi several times.

However, in such conventional methods, the information signal 112
Since the signal 111 indicating the starting position of the information area comes in from a separate system, a delay circuit or the like is required to match the phase of the two, which makes the circuit itself complicated and reduces the accuracy of knowing the starting position of the information area. The problem was that the information could be misread.

(Means for Solving the Problem) The problem with the prior art as described above is that the information area in which the information of the present invention is recorded is separated from other tracks by an identification area and at the beginning of the information area. When reproducing information from an information track having a start bit arranged, a predetermined signal is output when the identification area is detected, and the start position of the information area is determined by detecting the start bit using the output signal. This problem is solved by an information reproducing method characterized in that the information in the information area is sequentially reproduced based on the determined information.

(Function) - In the information reproducing method of the present invention as described above, when the start bit information is detected after the information in the identification area is detected, the next information is determined to be the first information in the information area. be able to.

Moreover, by using a combination of the on-track detection signal of the identification area and the detection signal of the start bit provided in the information area, a complex delay is required to match the phase of the signal indicating the position of the information area and the information signal. The accuracy of detecting the starting position of the information area is improved without the need to use a circuit.

(Example) The present invention will be described in detail below with reference to one drawing. In addition, in this example, information record #! The explanation is based on an optical card as a carrier.

FIG. 1 is an enlarged schematic diagram of the recording format of the information recording carrier according to the present invention.

FIG. 2 is a partially enlarged schematic diagram of an information track in the recording format shown in FIG. 1.

In FIG. 1, reference numeral 4 indicates one information track, and the information track is formed from a preamble area 21, an identification area 22, an information area 23, and an end bit 24. However, as shown in FIG.
o, and the information area 23 is formed from the start bit 3o and an information section of several bytes.
3 is modulated using the MFM modulation method. The preamble area 21 is provided for taking out a clock for information reproduction. As shown in FIG. 1, the end bits 24 are provided with information "01" and information "lo" alternately for each information track 4. Identification area 22
7, has a length of b bits in the C direction, and has information "l" at the left end in the C direction with 5 arrows.
O", the information "ot" is located at the right end, and the 4 bits in the center are strip-like information "1", which is approximately 1/2 the width of one bit or the width in the direction of arrow A. , information "1011110" having a reversal interval of 4T in the direction of arrow C.
An identification area of 1'' is formed.

Therefore, when the optical cart is played back as described above using the playback device shown in 6th U; , the reading position of the sensor array lO is on track! E is identified. Further, after information other than the information "10111101", that is, the information "tooooooi" obtained when the reading position of the sensor array 10 straddles two consecutive information tracks, is detected, the information "
10111101'' is detected, the sensor array lO
It is identified that the reading position has moved to a new information track. Furthermore, as described above, since the information "10" and "01" of the end bit 24 are provided in each information track at alternating pressure, the reading position of the sensor array 10 is continuously moved to a new information track. can be determined.

Moreover, in this embodiment, since the start bit 30 of the information "l" is provided at the beginning of the recording area 23, that is, immediately after the L identification area 22, the information "1otttt" is provided.
By detecting the information "1" after "ot" is detected, it is determined that it is the start bit 30, and the next detected information can be detected as the first information in the information area 23. can.

Next, the information reproducing method of this embodiment with the above configuration will be described in further detail.

FIG. 3 is a block diagram (C) of a detection circuit used in the information reproducing method of this embodiment. (In Figure 111, the binarization circuit 102
The process up to the signal 11O, which is digitized into binary data, is the same as that described in the prior art, but in this embodiment, the identification area detection circuit 103' uses the signal shown in FIG.
The signal shown in FIG. 3(b) is detected using a shift register, and a signal indicating on-track and a signal ttt' indicating moving to a new track are sent to the information acquisition circuit 106', and - the above-mentioned signal indicating on-track 114 to the information demodulation circuit. Next, the signal demodulated by the information demodulation circuit 104' and the signal 112' indicating the starting position of the information area are sent to the information acquisition circuit 106'. The end bit detection circuit 105 and signal 113 are similar to those shown in the prior art, and the second detection circuit 105 detects the end bit and outputs a signal indicating the end of information and a signal 113 indicating that the track has moved to a new track. The information is sent to the information acquisition circuit 106. In the information acquisition circuit 106, 111'.

Judging from the signals 112' and 113, the sensor array 10 is scanned multiple times for one track, and a correct signal is taken in once among the signals obtained.

Furthermore, a method for detecting the starting position of the information area in the above-mentioned recording format will be explained based on FIG. 4.

In FIG. 4, (a) shows a binary digitized signal at the time of on-track. In addition, the signals 21' and 2 in the figure
2', 23', 24', 30' and 31' are the respective areas in the information track 4 in FIGS. 1 and 2, that is,
preamble area 21, identification area 22, information area 23,
End bit 24. Start Beud 30. These signals correspond to the information portions 30 and are obtained from each region.

Moreover, the signal shown in (b) is the identification area detection circuit 103'.
This is a signal indicating on-track detected by. (C
) is a gate signal indicating the gate created by the on-track signal shown in (b). The signal shown in (d) is an information signal demodulated by the information demodulation circuit 104'.

When a "1" level is detected for the first time in the gate shown in (C) using the signal obtained as described above, it is determined as a start bit, and the next bit is the beginning of information. The information can be identified as the indicated bit, and the information can be sequentially reproduced.

As described above, in this embodiment, since the information signal and the signal indicating the starting position of the information area pass through the same system 112' and enter the information acquisition circuit 106', a delay circuit is used to match the phases of the two. The accuracy of knowing the starting position of the information area is also improved without the need for .

In this embodiment, the start bit to be provided at the beginning of the information area is information "1" consisting of 1 bit, but the present invention is not limited to this, and may be set to 2 bits or more. However, it may also have an inverted signal, such as information "101".

Further, the present invention cannot be applied to the reproduction of information from a record carrier such as a magneto-optical record carrier in which the direction of magnetization is reversed or a record carrier with concave and convex bits.

(58, Effect of Brightness) As explained above, according to the information reproducing method of tree 21j1, the accuracy of detecting the starting position of the information area is improved without using a complicated delay circuit or the like. Moreover, when a slow speed circuit or the like is used as in the past, the circuit itself becomes complicated and the accuracy of detecting information signals deteriorates.According to the present invention, such drawbacks are eliminated and the accuracy of detecting information signals is improved. It is effective in improving

[Brief explanation of the drawing]

FIG. 1 is a schematic partial enlarged view of the recording format of the optical card according to the present invention, FIG. 2 is a diagram for explaining the information area of the recording format shown in FIG. 1, and FIG. 3 is the L recording format. Block diagram of a circuit for detecting a signal of
The figure shows a binary signal to explain the method of detecting the starting position of the information area, Figure 5 is a schematic diagram showing the recording format of a conventional optical cart, and Figure 6 is a diagram of the optical card playback device. Schematic structure r & diagram, Figure 7 is a diagram for explaining the principle of reading the identification area, Figure 8 is a diagram showing a binarized signal corresponding to the identification area shown in Figure 7, and Figure 9 is the diagram shown in Figure 5. FIG. 2 is a block diagram showing a circuit for detecting signals from the information track of the nine carts shown in FIG. 1... Optical card, 4... Information track, 21...
Preamble area, 22... Identification area, 23... Information area, 24... End bit, 30... Start bit, 31... Information section. Agent Patent Attorney Yama 11'' Minoru Plan 1 Figure 2 Figure 4 Figure 5 Figure 4 - Sue Figure 6 Figure 7 Figure 8 Figure 1i-

Claims (1)

[Claims] When reproducing information from an information track that has an information area where information is recorded, an identification area for separating and identifying it from other tracks, and a start bit placed at the beginning of the information area, when the identification area is detected. An information reproducing method comprising: outputting a predetermined signal, detecting the start bit using the output signal to determine the start position of the information area, and sequentially reproducing information within the information area.