JPS6011377B2 - optical signal regenerator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical signal reproducing apparatus for reproducing information recorded on a tape-shaped optical recording medium as a group of a plurality of bits (bit groups) in the tape width direction.

Possible reproduction methods for this type of device include a parallel reproduction method in which each bit of one group is detected simultaneously, and a serial reproduction method in which detection is performed by scanning in the width direction of the tape.

Among these, the parallel playback method is simple in principle, but if there is variation in the tape width direction as the tape runs, the light receiving state of the photodetector when detecting the Nth column may be different from time to time. In some cases, the nth item from the top may become the n2th item from the top at time t2.

FIG. 1 illustrates this relationship, where a indicates a group of recorded information bits, b indicates a photodetector array, and c indicates a point of variation in the width direction of the tape. Therefore, in this case, in order to continue reproducing a normal signal, it is necessary to detect the position in the tape width direction that changes from time to time, and to detect the bits from the 1st bit (n,) to the Sth bit (n8). A complex logic circuit is required to determine which photodetector is present. The present invention relates to a serial reproduction method, which is a second method, and uses an optical recording device to record positional information A on a tape-shaped optical recording medium shown in FIG.
This system detects information recorded in correspondence with each other, regardless of the tape running direction or tape position fluctuation, and reproduces the correct time-series signal. For example, as shown in Figure 2, one group of If all bits A are set to "1" at the beginning of bit group D, the time from the time when the first bit is detected to the time when the nth bit is detected will be constant if the frequency at which the sensor is scanned is constant. Since it is a scan,
The position of the n-th bit can be accompanied based on the time when the sensible bit A in the first column is detected. On the other hand, as such a photodetector, a photodiode image sensor or a CC
Technologies such as the D-image sensor have been put into practical use.

However, in this serial reproduction method, it is desirable to start and end sensor scanning when the entire Sekiguchi area of the photodetector is included within the area of the bit. This is because the further away from this condition the more the bit area protrudes from the aperture area of the detector.
This is because the margin for judgment is small compared to the threshold level for judgment of 1", and the S/N of the final signal is therefore poor. Therefore, the signal is placed as close to the center of the bit group as possible. One possible method for scanning a portion is to scan the sesor multiple times within the time it takes for all the bit groups to cross over the sensor by feeding the tape.

However, as the size of the sensor's entrance approaches the size of the bit, and as the information density of a bit group (one group) increases, it is possible to obtain a signal that scans the center of the bit. In order to make a judgment with a large margin, if the number of bits in a bit group (one group) is n, and the scanning time for scanning one bit is t, then the repetition frequency f = poison and earth, which is higher than necessary and extremely high. It is necessary to scan the sensor in frequency, which becomes a bottleneck for the regeneration system. In order to solve this problem, the present invention provides a means for reliably reproducing a time-series signal by scanning the center of one group of bits in one scan, eliminating the drawbacks of the above-mentioned serial reproduction method. The present invention provides an optical signal reproducing device equipped with the following.

The configuration of one embodiment of the present invention will be described below with reference to FIGS. 3, 4, and 5. In this embodiment, an audio signal recorded as a 13-bit PCM signal on an optical recording medium is reproduced.

In Figure 2, B is the opaque area of the tape, C is the translucent area,
D is an amorphous recording material in which information is recorded with one group of 13-bit PCM signals, and A is position information (1-bit recording in the present invention) recorded in correspondence with one group. FIG. 3 is a diagram illustrating an integrated image sensor for detecting a position and an image sensor for detecting bit groups used as an embodiment of the present invention.

Further, FIGS. 4a and 4b show respective scanning line diagrams on the tape surface of each sensor in FIG. 3. FIG. 5 is a block diagram of the apparatus for reproducing the above-mentioned tape.

In Figure 3, 1 is a self-scanning sensor that detects position information (13 in Figures 4 and 5), and 3 is a group of bits (13 in Figures 4 and 5).
A self-scanning sesor that reads out 12) in FIGS. 4 and 5;
2 is a clock pulse generator that drives a self-scanning sensor that detects position information, and 4 is a clock pulse generator that drives a self-scanning sensor 3 that reads out a group of bits.

The self-scanning sensor 1 that detects position information is configured with only the number of bits sufficient to compensate for fluctuations in the tape in the direction perpendicular to the tape running direction, and the number of bits sufficient to reproduce the bit group as described above. Fast repetition is possible without the need for Therefore, the sensor 1 that detects position information can be repeatedly scanned several times faster than the sensor 3 that detects bit groups. Figure 4a shows the sensor 1 in Figure 3,
3 shows the scanning state of each sensor on the tape in detail. Also, in Figure 5, 8 is 1
Position information 13 recorded in correspondence with bit group 12 of a group and recorded tape recorded as bit group 12 of one group (audio signal recorded as a PCM signal with 13 bits), 11 is Caesar, 10 9 is a spherical lens, 9 is a cylindrical lens, 7 is an enlarged projection lens, and 14 is an image sensor shown in FIG.

In the above configuration, the parallel laser beam emitted from the laser 11 is converted into an elliptical beam containing one group of bits 12 and position information 13 recorded on the recorded tape 8 by the combination of the spherical lens 10 and the cylindrical lens 9. The tape 8 is irradiated with spot light.

One group of bits 12 and position information 13 obtained by the irradiation are irradiated onto the surface of the image sensor 13 as an enlarged projected image via the enlarged projection lens 7 due to the transmittance of the tape 8. At this time, in order to reliably read information even if the tape 8 fluctuates in the width direction of the tape 8, the position information 13 and the bit group 12 of one group are set relative to the center of the fluctuation of the tape 8 in the width direction. It is important to set (adjust) in advance the image sensor 1 that detects the information 13 and the image sensor 3 that detects one group of bits 12 at the center of the direction in which the photo sensors are arranged. 2 is a clock pulse generator that drives the position information detection sensor 1 as described above, and 5 is a threshold so as to output a positive output only when the position information 13 of the tape 8 crosses the position information detection sensor 1. The comparator 4 is a clock pulse generator that starts scanning when it receives a positive signal from the comparator 5 and drives the sensor 3 that detects one group of bits 12.

The position information detection sensor 1 starts detecting at a repeating high speed by the clock pulse generator 2, and when the output of the comparator 5 appears, the sensor 3 is operated via the clock pulse generator 4.

Therefore, when the output of the comparator 5 appears, the image of one group of bits 12 recorded on the tape 8 is displayed on the bit group detection image sensor 3.
Since the image is projected with the center of the aperture group aligned with the center of the tape running direction, when the sensor 3 starts scanning at that moment, the output of the sensor 3 will be such that the center position of the bit group and the closed surface of the sensor 3 are aligned. An ideal output at the time of coincidence is obtained at the output terminal 6.

The above explanation is an example in which position information is provided at the tip of one group shown in FIG. 2, but as shown in FIG. It can be detected in the same way even if the position information sensor 1 is recorded in parallel, and it can be detected if the position information mark is included in at least one of the arrayed photo sensors. .

In addition, as shown in FIG. 6, the size of the sensor for detecting position information is made large enough to compensate for the fluctuation of the tape 8 in the tape width direction. It is also possible to detect position information 13.

Here, 15 is a comparator that shapes the output from the position information detection sensor 1, and 16 is a clock pulse and start pulse generator that operates the bit group readout sensor 3 when the output of the comparator 15 appears. be. Note that the output of the bit group reading sensor 3 is output to the output terminal 17. As described above, according to the optical signal reproducing apparatus according to the present invention, the position where the signal bit exists can be detected regardless of the vertical movement associated with tape running, so that the image sensor is always detected at the center of the signal bit. Since scanning is performed only once for a portion where one signal exists, there is no problem with the repetition frequency of the sensor due to an increase in the number of bits, and signal processing is also simple.

[Brief explanation of the drawing]

FIG. 1 is a diagram for explaining problems in the parallel optical signal reproduction system, FIG. 2 is a diagram showing the configuration of a recorded tape used in an optical signal reproduction device according to an embodiment of the present invention, and FIG. A configuration diagram of an image sensor used as an embodiment of the present invention, FIGS. 4a and 4b are scanning line diagrams of the image sensor shown in FIG. 3 in tape form, and FIG. 5 is an overall configuration diagram of an apparatus according to the present invention , FIG. 6 is a diagram showing the main parts of another embodiment of the same device. 1... Sensor for position information detection, 2, 4...
...Clock pulse generator, 3...Bit group detection sensor, 5...Comparator, 12...
...1 group of bits, 13...Position information. Figure 6 Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] 1. A tape-shaped optical recording medium having one group of information recorded as a line of information in a direction perpendicular to the tape running direction and positional information recorded corresponding to this one group of information, and a tape-shaped optical recording medium having A corresponding position information detector that performs high-speed repetitive scanning and an information detector that reproduces the information of the one group as a time series signal are provided, and the information detector is driven by the detection output of the position information detector. An optical signal reproducing device having means.