JPS59188874A - Retrieving device for target track position - Google Patents

Abstract

PURPOSE:To shift a carriage holding a pickup in the opposite direction to that of a quick traversing mode in case a light spot stops at an area where no program is recorded after the rough retrieval and to attain the subsequent fine retrieval for a video disk player, etc. CONSTITUTION:In case a light spot stops at an area where no program is recorded after the rough retrieval, the contents of both frame information memory 9 and address information memory 10 are reset and kept as they are since both frame and address information are not inserted at a prescribed horizontal scan position. A microcomputer 15 reads the contents of the memory 9 or 10 out of the vertical synchronizing signal after a fixed period of time. It is decided whether the program is recorded or not by checking whether the contents of memories 9 and 10 are reset and kept as they are. Then a carriage 4 holding a pickup 3 is shifted in the opposite direction as that of a quick traversing mode and reset to a program record area after detecting that the rough retrieval stop position is coincident with the area where no program is recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a high-speed search for a target track position on a rotating disk in a video disk player, etc. This is related to preventing the impossibility of secret searches.

[Prior art]

2. Description of the Related Art There is a playback device such as an optical video disc player, which records a video or audio signal in high quality on a recording medium and plays back the signal from the trace (hereinafter abbreviated as a track) of the recorded signal. This device focuses a light spot generated from a light source onto a disk-shaped rotating recording medium (hereinafter abbreviated as disk), and the light spot is located on a track recorded concentrically or spirally on the disk. The light reflected from the disk at the optical spot is detected by a photodetector and the signal is read. In the above playback device, it is easy to move the reading unit in the radial direction of the disc, and this movement can change the progress of the program.
By recording the address information serving as the address in each information track, each information track can be searched independently by specifying an arbitrary address. - Target track # can be randomly accessed. The entire conventional control circuit is shown in FIG. In the figure, 1 is equipped with a disk, 2 is a motor for rotating the disk, 6 is a pickup that irradiates a focused spot of laser light onto the disk 1 and obtains an electric signal from the reflected light, 4 is equipped with a pick amplifier 6, The disk 1 is transferred under the control of the transfer control circuit 14.
5 is an amplifier circuit, 6 is a video signal demodulation circuit, and 71 is a lead-in of a disc recorded in a predetermined horizontal scanning position during the vertical blanking period of a video signal using a phase modulation method according to the code standard. A code demodulation circuit is used to extract and modulate frame information such as lead-out and address information, 8 is a pattern check circuit for determining whether the demodulated code is frame information or address information, and 9 is a demodulated code demodulation circuit. 1. A frame information memory 10 is used to store demodulated address information, and an address information memory 11 is used to separate a synchronization signal from a reproduced video signal. 121d is an address information memory 10. 13 is a tracking control circuit for controlling the light spot to follow the information recording trunk deflection due to eccentricity of the disk; 14 is a disk; a transfer control circuit 1 for controlling the transfer of a gear ridge equipped with a pickup in the radial direction of the disk according to playback;
5 is a microcomputer that controls the entire system;
Reference numeral 16 denotes a track crossing detection circuit for detecting the number of track crossings in the high speed feed mode during a search. When searching in this system, K (r-1,
First, the current playback address is read from the address information memory 10 into the microcomputer 15, and, although not shown here, the microcomputer 15 calculates the difference from the target address specified by the operation console, and also determines the search direction. After the determination, the tracking control circuit is turned off and the carriage 4 carrying the pick amplifier 3 is transported at high speed to perform a rough search. At this time, a sine wave signal as shown in FIG. 2(3) is obtained from the tracking control circuit 13 every time the light spot crosses the track. Therefore, the number of this sine wave signal indicates the number of tracks crossed by the light spot.The track crossing detection circuit 16 shapes the waveform of this sine wave signal into a rectangular wave as shown in FIG. 2(b). The converted data is input to the microcomputer 15.

The microcomputer 15 detects, for example, rising edges of this input signal, counts the number of rising edges, and calculates the number of crossed tracks. When the difference in the number of tracks crossing the target value reaches, for example, within 50 tracks, the tracking control circuit 13 is turned on, which does not stop high-speed feeding.

Thereafter, the address information inserted into the vertical retrace period of the reproduced video signal is read by the IE microcomputer 15.

The number N of tracks up to the target address is determined from this address information, and N track skip pulses are applied to the tracking control circuit 13 to move the light spot to perform a fine search. Thereafter, it is determined whether or not the target address has been reached, and this process is repeated every time the target address is reached.

By the way, the number of tracks on which programs are recorded differs depending on each disc, and areas where no programs are recorded have a black level video signal, address information,
There are various types of tenosques, such as those in which only black level video signals are recorded. Therefore, on a disc where only black level video signals are recorded in areas where programs are not recorded, if you try to search all addresses that are greater than or equal to the number of tracks in which BLJ-grams are recorded,
For example, if you try to search for 40,000 addresses on a TisF where programs are only recorded up to 30,000 addresses, the problem will occur, and after a rough search, the light spot will stop in the area where no programs are recorded, but after that, the address information Since it is not possible to obtain the following information, it is not possible to proceed to the next dense search operation, and subsequent operations become impossible.

If a search is performed near the boundary between an area where a program has been recorded and an area where a program has not yet been recorded, the stop position of the light spot after the rough search may be shifted by several hundred tracks due to the inertia of the carriage 4 on which the pickup 3 is mounted, and the program may be lost. If the vehicle stops in an unrecorded area, there is a problem in that address information cannot be obtained and the target address cannot be searched.

[Purpose of the invention]

The present invention has been made in order to solve the problems of the prior art as described above, and therefore, the purpose of the present invention is to solve the following problems: Another object of the present invention is to provide a target track position retrieval device that enables subsequent detailed retrieval.

[Summary of the invention]

Therefore, in the present invention, after detecting that the rough search stop position is in an area where no program is recorded,
A method was adopted in which the carriage 4 carrying the pickup filter was transported in the opposite direction to the direction in which it was fed at high speed and returned to the 7' program recording area.

Embodiment Hereinafter, an embodiment of the present invention will be described and explained with reference to the Bronch diagram of FIG. 3. In FIG.

The frame information memory 9 and address information memory 10 are
Frame information inserted at a predetermined horizontal scanning position after being reset by a vertical synchronization signal.

Detect address information 1. It is set and held at the next vertical synchronization signal switch. However, on a disc in which only a black level video signal is recorded in an area where no program is recorded, if the light spot stops in the area where no program is recorded after a rough search, the light spot may be moved to a predetermined horizontal scanning position. Since frame information and address information are not inserted into the frame information memory 9 and address information memory 10, the contents of the frame information memory 9 and address information memory 10 remain reset. By reading the contents of information memory 10 and detecting whether the contents of memory 9 and memory 10 remain reset, it can be determined whether a program is recorded.

FIG. 4 shows a flowchart of the control algorithm at the time of search in the embodiment of the present invention shown in FIG. When performing a search, the difference between the current address and the target address is determined, the search direction is determined, and this is stored in the search direction memory 17. After that, tracking control circuit 1
The carriage 4 carrying the pickup 6 is transported at high speed with the filter turned off, and the number of crossed tracks is calculated from the rectangular wave obtained from the track crossing detection circuit 16. When the difference in the number of tracks crossing the target value reaches within 50 tracks, the tracking control circuit 13 is turned on to perform normal reproduction. At this time, the microcomputer 15 determines that if the contents of the frame information memory 9 or the address information memory 10 are up to 1, which is reset, the program is outside the recorded range. According to the search direction stored in the search strategy memory 17, the carriage 4 is searched from the inner circumference to the outer circumference, from the outer circumference to the inner circumference (or, when the carriage 4 is searched from the outer circumference to the inner circumference,
1. The information is transferred from the inner circumference to the outer circumference until the contents of the frame information memory 9 or the address information memory 10 are set. When the address information memory 10 is set in the frame information memory 9 or j, the microcomputer 15 detects that the program has reached the area where the program is recorded, and in the normal playback mode, the vertical blanking line 1 of each track is set. After reading the address information inserted in the corresponding part, output the trunk jump pulse if according to the difference between the address information at this time and the target address, and then read the address information @ in normal playback mode and move to the target address. 1. Determine whether it is correct or not. If the target address exists, IC+4 is reached, and this operation is repeated until the target address is reached. On the other hand, if the number of tracks exceeds the number of tracks in which the program is recorded, the frame information memory
Alternatively, the address information memory 1o is reset. At this time, the microcomputer 15 determines that the target address does not exist, and moves the carriage 4 again in the direction stored in the search direction memory 17 and in the opposite direction until the frame information memory 9 or Id address information memory 10 is set. After the character signal generation circuit 1
2, the fact that the target address does not exist is displayed on the bibliography screen to notify the user.

FIG. 5 shows another embodiment of the invention. In FIG. 5, a program area determination circuit 18 is a circuit for determining whether a light spot is in a program area, and is composed of a line selector and an R-S flip-flop.
A reproduced video signal as shown in FIG. 61(a) is input from the demodulation circuit 6. The vertical retrace stroke of the reproduced video signal [...in which,
Frame information such as lead-in information indicating the playback start position of the disc and address information are inserted in a predetermined horizontal scanning period.The line selector in the program area discrimination circuit 18 inserts this information in the playback video signal. The horizontal scanning position is selected and data is extracted. At the rising edge of this data signal, an R, -8 flip-flop is set, and this output is input to the microcomputer 15iC as a program area discrimination signal.

The microcomputer 15 determines whether the program area discrimination signal is at a high level after a certain period of time from the vertical synchronization signal.
By reading whether the level is low, it is determined whether information is recorded at a predetermined horizontal scanning position. )V-mu information is also 1. Since the address information is inserted every other field, in order to determine that the program is outside the area where the program is recorded, it is detected that the program area discrimination signal is at a low level for more than two fields. to make the determination.

FIG. 7 is a flowchart showing the control algorithm at the time of search in the embodiment shown in FIG. Even in an unrecorded area, the pickup means can be reliably positioned on a track in which designated address information is recorded,
Even when the number of information recording tracks is exceeded, the user can be informed of this, and the search accuracy and operability can be improved.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a control circuit of a conventional target track position search device, FIG. 2 is a waveform diagram showing input and output waveforms of a track crossing detection circuit, and FIG. 1 is a block diagram showing an embodiment of the present invention. 4 is a flowchart showing the control algorithm of the embodiment shown in FIG. 5, FIG. 5 is a block diagram showing another embodiment of the present invention, and FIG. FIG. 7 is a flowchart showing the control algorithm of the embodiment of FIG. 1.Disc 2.Motor 3.Pickup
4 Carriage 7...Data demodulation circuit 8...Pattern check circuit 9.Frame information memory 10...
Address transition memory 11...Synchronization separation circuit 12...
・Character signal generation circuit 13...Tracking control circuit 14...Transfer control circuit 15 Microcomputer 16...Trunk intersection detection circuit 17...Search direction memory 1 day...Program area discrimination circuit

Claims (1)

[Claims] 1) a signal reproducing means for reproducing a signal from an information track recorded on a rotating disk; a moving means for moving the reproducing means in a direction across the information track on the rotating disk; A means for detecting and counting the number of times the reproducing means traverses the information track from the reproducing output, and comparing a given target position signal representing the target track position with the counted value by the counting means, so that the two are in a predetermined relationship. 7. In the target track position search device, the target track position search device has means for stopping the movement of the reproduction means by the moving means when the target track position is reached, and performs a rough search for the target track position. Means is provided for determining from the playback output whether or not the stop position is in a non-program area where trunk address information is not recorded, and when the stop position is in the non-program area, the playback means is moved by the moving means. 1. A target track position retrieval device characterized in that the target track position retrieval device is configured to return in the opposite direction.