JPS5921101B2 - Information signal reproducing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an information signal reproducing device, in which a scanner for picking up and reproducing a recorded information signal on a spiral or concentric information track is arranged in a direction perpendicular to the running direction of the information track. Random access or search operation can be enhanced by switching the number of reproduction address signals indicating the same track number, which is necessary to determine whether the reproduced track number is correct or incorrect, depending on the movement speed. It is an object of the present invention to provide an information signal reproducing device that can perform high-quality and high-speed reproduction.

A disc-shaped or cylindrical information recording medium (hereinafter referred to as a disk) on which an information signal such as a video signal is recorded by forming a spiral or concentric information track as a geometric shape change, or a magnetic When reproducing a recorded magnetic recording medium such as a magnetic sheet, in an apparatus that reproduces the magnetic recording medium or an apparatus that reproduces data without contacting the disk (by changing the intensity of light) with a scanner that scans the disk, The absence of track grooves allows the scanning element to traverse freely from one track to another.

Furthermore, in a device for reproducing recorded information signals by detecting, for example, changes in capacitance when a scanning element that scans the disk comes into contact with the disk, the applicant of the present application previously filed a patent application filed in 1986-3.
When playing back a disc in which a tracking control reference signal is recorded approximately in the middle between tracks of adjacent information signals, as proposed in JP-A No. 8809/1988-123205, Since there are no track grooves, the scanning element can move across the tracks from one track to another without damaging the disk.

Therefore, in each of the above devices, reproduction output can always be obtained even when the scanner is moved to a desired predetermined position. When the above-mentioned scanner is moved in the track scanning direction, which is a direction perpendicular to the disk surface, faster than during normal playback, the recorded information will not be continuously played back, and there will be parts that can be read and parts that cannot. The higher the transfer speed, the more areas that cannot be read. Therefore,
As the speed increases, the number of cases in which the number indicating each track recorded in advance together with the information signal, that is, the track number, cannot be read increases. On the other hand, since the track number read may not show the correct value due to noise or dropout, it is more reliable to read the same number two or more times in order to read the correct value. FIG. 1 is a partially cut-away plan view of an example of a disk-shaped information recording medium. On the disk, an address signal indicating a track number is recorded at a position indicated by 2 superimposed on a part of an information track 1. In this example, four identical track numbers are recorded for one rotation of the disk.

The track number is set so that its value increases by one each time an information track enters the inner track, and the track number of the outermost track is set to 0. When playing at normal speed, four tracks with the same number will be played. When the speed is twice the normal speed (when the disk rotates at the same number of rotations as normal and the scanner is sent at twice the normal speed), the inner circumference or Since it is necessary to jump the scanning element to the outer periphery, it is necessary to jump up the same track number to the outer periphery, so it depends on which part you want to jump to the inner periphery or the outer periphery.
Can read more than one. In addition, when the rotation speed is the same as the rotation speed during normal disk playback, and the scanning element feed speed is set to 5 times the speed during normal playback (during 5x speed playback), one track is transferred four times per disk rotation. Since it is necessary to move the scanning element up to the inner or outer circumference, it becomes impossible to read two or more of the same track numbers. If the speed is increased further, it will not be possible to read the numbers of all the tracks, so it is necessary to read the track numbers every few tracks, or at least scan the same track while the disk rotates half a revolution. It is necessary to jump the track to the inner or outer circumference and keep tracking for at least half a rotation of the disk so that two or more identical track numbers can be read. However, according to this method, the faster the scanner moves in the direction perpendicular to the information track scanning direction (disk radial direction), the better the tracking performance (which is necessary for high-speed random access). The drawback was that the circuit was complicated and expensive. The present invention eliminates the above-mentioned drawbacks, and an embodiment thereof will be described below with reference to FIG.

FIG. 2 shows a block system diagram of an embodiment of the apparatus of the present invention. In the figure, 3 is a pick-up (scanner), and the signal reproduced from a disk (not shown) by this is demodulated by a demodulator 4 to obtain a video signal! It will be done. During the vertical blanking period of this video signal, a coded address signal representing a track number is inserted in advance and recorded on the disk, so the demodulated video signal is supplied to the data demodulator 5, where the address signal is only is retrieved and added to memory 6. The memory 6 records data until the next data is input, and when the next data is input, the stored data is transferred to the memory 7. Memory 7 stores the data until the next data is added from memory 6. A comparator 8 compares the contents of the memories 6 and 7, and when both have the same contents, opens the gate 9 and supplies the contents of the memory 6 to the comparator 10.

The comparator 10 compares the memory contents of the memory 6 with the memory contents of the memory 6, which stores the specified address representing the desired truck number specified by the keyboard 11, and calculates the difference (address difference). A corresponding signal is applied to the control circuit 13. The control circuit 13 sends a control signal to the pickup 3 to move the pickup 3 in the radial direction of the disk. At this time, when the address difference in the comparator 10 is large, the pick-up 3 is moved quickly, and when the address difference is small, the pick-up 3 is moved at a slow speed. When the control circuit 13 is sending out a control signal to move the pickup 3 quickly, the memory 6 and the memory 7 are sent to the comparator 8.
The control circuit 13 is configured to output a control signal to open the gate 9 even if the contents do not match. In other words, when the difference between the designated address and the reproduced address is large and the pick-up 3 moves quickly to find the designated address position to be scanned, the reproduced address signal is passed through the comparator 10 in one go. It is compared with the designated address signal, but when the pick-up 3 approaches the designated track and the speed of the pick-up 3 in the disk radial direction is slow, the gate 9 will not open unless the address signal representing the same track number is reproduced two or more times. First, when an address signal with the same track number is reproduced twice or more, it is assigned a regular track number, and the comparator 8 increases the number of input address signals according to the above value, and , control can be performed to generate a signal that opens the gate 9 when the number of address signals to be compared indicates the same track number.

As described above, the information signal reproducing apparatus according to the present invention includes means for inputting a designated address signal indicating a desired information track position, a demodulator for demodulating a recorded address signal from a reproduced signal from a scanner, and A memory circuit to which a demodulated address signal from a demodulator is sequentially supplied, stores a plurality of demodulated address signals, and whose stored contents are sequentially updated each time the recorded address signal is reproduced, and each of the memory circuits. a comparison circuit that is supplied with storage address signals, compares at least the value of the latest demodulated address signal stored in the memory circuit with the value of the specified address signal, and outputs a signal representing the difference between the two values; When a signal is supplied from the circuit and the value is greater than a certain value, a signal is generated to move the scanning element at a high speed, and when the above value is smaller than the certain value, a signal is generated and output according to the value. generates a signal for moving the scanning element at a low speed, and causes the comparison circuit to increase the number of comparisons of input demodulated address signals in accordance with the above value, so that the number of address signals to be compared are on the same track. When indicating a track number, the address signal is compared with the designated address signal, and a signal of the value obtained is output from the comparison circuit, and when the same track number is not indicated, the address signal and the designated address signal are compared. Because it is constructed with a control circuit that controls the suspension of the track number, it is possible to read the track number more efficiently than before. Therefore, random access operations and search operations can be performed with high quality and high speed, the circuit configuration can be simplified compared to the conventional one, and two or more address signals indicating the same track number can be reproduced in succession. When the track number is determined to be correct when the track number is correct, if two or more address signals indicating the same track number cannot be read in a row, the moving speed of the scanner is further slowed down or stopped. It has several features, such as being able to actively read the track number, improving track search accuracy, and suppressing unnecessary movement of the scanner due to misreading of the track number.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway plan view of an example of a general information recording medium that can be used in the apparatus of the present invention, and FIG. 2 is a block diagram of an embodiment of the apparatus of the present invention. 2... Address signal recording position indicating track number, 3... Pick up, 8, 10...
-Comparator, 9...gate, 13...control circuit.

Claims (1)

[Scope of Claims] 1. On a spiral or concentric information track, there are i address signals representing a predetermined track number for each information track together with the information signal (however, i is 2 or more). When searching for a desired information track position on a recording medium on which information is recorded (natural number), a scanner for picking up and reproducing a recorded signal is relatively scanned on the information recording track in a direction perpendicular to the information track scanning direction. An information signal reproducing apparatus that moves to a location includes means for inputting a designated address signal indicating a desired information track position, a demodulator for demodulating a recorded address signal from a reproduced signal from the scanner, and a means for inputting a designated address signal indicating a desired information track position; A memory circuit to which a demodulated address signal is sequentially supplied, stores a plurality of demodulated address signals, and whose stored contents are sequentially updated each time the recorded address signal is reproduced, and each stored address signal of the memory circuit. a comparison circuit which compares at least the value of the latest demodulated address signal stored in the memory circuit with the value of the specified address signal and outputs a signal representing the difference between the two values; When a signal is supplied and the value is greater than a certain value, a signal is generated to move the scanning element at a high speed, and when the above value is smaller than the certain value, a signal is generated and outputted that causes the scanning element to move at a low speed corresponding to that value. generates a signal for moving the scanning element, and at the same time causes the comparison circuit to increase the number of input demodulated address signals to be compared in accordance with the above value, so that the number of address signals to be compared indicates the same track number. Sometimes, the comparison circuit outputs a signal with a value obtained by comparing the address signal with the specified address signal, and when the same track number is not indicated, the comparison between the address signal and the specified address signal is stopped. 1. An information signal reproducing device comprising: a control circuit that performs control. 2 In the above recording medium, address signals indicating the same track number are recorded n times (however, n≧2) at equal angular intervals on one information track per revolution, and the above control circuit is connected to the above comparison circuit. The moving speed of the scanning element when the value of the output signal of is greater than the constant value is set to be at least n+1 times the moving speed during normal reproduction, and the value of the output signal of the comparator circuit is the constant value. 2. The information signal reproducing apparatus according to claim 1, wherein the moving speed of the scanning element is set to be less than n+1 times the moving speed during normal reproduction. 3. When the value of the output signal of the comparator circuit is smaller than the constant value, the control circuit detects that two or more address signals indicating the same track number cannot be read in succession by the comparator circuit; Claims 1 or 2 are characterized in that the scanner is configured to generate and output a signal to further reduce or stop the moving speed of the scanner.
The information signal reproducing device described in Section 1.