JPS5883369A - Information reproduction method and apparatus - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention generally relates to a device for reproducing information recorded on a selected target track on a recording disk by moving the information reproducing device at high speed.

In conventional configurations, a reading light beam is directed onto a selected one of a plurality of substantially circular and concentric recording tracks on a rotatable recording disk. The intensity of the beam is modulated by the information being recorded. This information includes unique address signals for each track. A device detects the modulated beam and generates a playback signal representing the recorded information.

The search style compares the current address with the target address,
A device applies drive signals in a predetermined order to the carriage motor depending on the remaining distance to the target track. The speed of the carriage motor is such that the reading beam is
When the predetermined distance threshold is reached, it is lowered step by step one after another. During the final stages of carriage communication, a movable mirror steps the beam radially one track distance during each revolution of the disk, thus causing it to enter the target track in the regenerated state.

When the device described above has no indication of the trunk currently being scanned and therefore no indication of the remaining radial distance to the target track, the device optimally directs the reading beam towards the target track. There is a risk that it will not drive. Accordingly, it is appreciated that there is a need for a device that provides a more accurate indication of the current position of an information reproducing device relative to a target track, allowing the device to move faster in the direction of the target track without overshoot. Good morning. This invention meets this need.

The present invention is implemented as an apparatus and related method for reproducing information from a selected target track among a plurality of substantially circular concentric recording tracks on a rotatable recording disk. The information is reproduced by an information reproduction device. This information reproducing device operates while the disc rotates in a predetermined manner.
Scan a selected radius of the disk. The recorded information may include, for example, a video signal, along with a unique address identifying each video frame.

The device is then operative to play back the selected target video frame recorded on the target track.

Separate video frames can be recorded on each track. In this case - the disk is rotated with a constant angular velocity, regardless of the radius of the scanned track. In return, the video signal can be recorded with a more uniform recording density. In this case, the 7 tracks recorded on each track
The number of frames is variable and the disk is rotated at an angular velocity that is inversely proportional to the radius of the track. In this way, the disk
All track radii are passed through the information reproducing device at the same linear speed. In the former case, the entire target track is recording the target video frame, while in the latter case, only a portion of the target track is recording the target frame.

The apparatus includes coarse positioning means for moving the information reproducing apparatus at a predetermined radial speed relative to the disk in the direction of the target track, and the coarse positioning means moves the information reproducing apparatus to the vicinity of the target track. and fine positioning means operative to move the apparatus incrementally from track to trunk until the target track is reached. During each rotation, the information reproducing device t
- incrementally move across a predetermined plurality of tracks; This greatly reduces the time required to move the device to a position where information recorded on the target track can be reproduced.

Other aspects and advantages of the invention will become apparent from the following description of a preferred embodiment. FIG.
An apparatus is shown for reproducing information from nine selected target tracks on a disk with radial movement relative to the disk. The disk has a plurality of closely spaced, generally circular, concentric recording tracks, each track recording a video signal representing one video frame, and each vertical period having a unique frame or track address. Signals are provided. (That is, there are two address signals per track.) The device uses a spindle motor 15 to rotate the recording disk 13 at a predetermined constant angular velocity, and a read beam 11 to a selected track of the rotating disk. Focusing optical device f1
17 and an objective lens 19. The read beam is reflected by the disk producing a reflected beam 21 whose intensity is modulated according to the information being recorded. An objective lens and optics direct this reflected beam to a detector 23, which detects and demodulates the modulated intensity of the beam to generate a baseband-video signal g corresponding to the information being recorded. . This video signal is coupled via line 25 to both the monitor 2T and the address reproduction and estimating circuit 29. The monitor displays the video signal reproduced from the target track in real time, and the address recovery circuit detects address signals within successive vertical periods of the video signal using conventional methods. Thereafter, the address recovery circuit updates address register 30 with each detected track address signal.

The apparatus further includes a coarse positioner and a fine positioner for controllably moving the reading beam 11 radially relative to the disk 13 toward selected target tracks on the disk. A coarse positioner is configured to move the beam t- at one of two relatively high radial velocities (e.g., 100 and 500 tracks per revolution of the disk).
A fine positioning device comprising a carriage motor 31 and suitable gearing for moving the optical system 17 is provided within the optical system 17 to move the carriage over a relatively small area (e.g. about 50 tracks in either direction). Includes a movable mirror (not shown) for controllably adjusting the point of incidence of the beam on the disk. When a user wishes to reproduce information recorded on a selected target track on the disk 130, the address of the target track is A special target address code signal representing the target address code is input to 135. Function generator 3T compares this target address signal with the address signal currently stored in address register 30. According to a predetermined algorithm, which will be explained later, a function generator determines the radial separation between the current track and the target track and outputs appropriate control signals to control the carriage motor 31 and the original track. The movable mirror 17 is controllably driven to move the reading beam 11 toward the target track. These control signals are sequenced such that the beam reaches the target track in a much shorter time than with conventional devices of this type.

In the present invention, the carriage motor 31 is driven at a predetermined speed (or sequence of speeds) until the reading beam 11 has moved within a predetermined number of tracks from the target track, and after reaching this range, Optical equipment ft17 revisited @!
For each half rotation of the disk 13, the beam is
Jump incrementally from one track to the next multiple times. By moving the beam radially relative to the disk in this manner, and in particular by moving it incrementally a predetermined number of times during each half-rotation of the disk, the target track is reached and recorded thereon. The nominal time required to ascertain the information contained in the system is significantly reduced.

More specifically, the coarse positioning device includes a daughter 41 that controllably drives the carriage motor 31 in a predetermined manner. The function generator 3T sends a
43 m to 43 d, a plurality of speed commands are output. This speed command controllably adjusts the DC drive signal coupled to the carriage motor via @45. The tachometer returns a carriage tachometer signal, representative of the angular velocity of the carriage motor, to the track scan driver via @47 to facilitate this speed control operation. Additionally, a DC tracking error signal is coupled via line 49 to the track scanning driver to controllably move the carriage motor to reduce any steady state runout of the movable mirror of the optical system iT. let

Track scanning driver 39 is shown in detail in FIG. It receives speed commands from function generator 37 via lines 943 and 43d and converts these signals into suitable DC drive signals which are coupled to carriage motor 31 via line 45. The driver includes a speed control digital-to-analog (D/A) converter 51 that converts the two speed commands received from lines 43 & and 43i into corresponding DC voltage signals, and converts this DC signal from a function generator. Forward direction l according to forward and reverse direction signals received via lines 43c and 43d.
! i! 55 or an analog switch 53 pointing in the opposite direction @57. A first inverting amplifier 59 connects the reverse direction line 5
If there is a signal on line 49, that signal is added to the DC tracking error signal supplied from line 49. If there is a signal in the forward direction @SS, the second inverting amplifier 61 transfers that signal to the first
amplifier 59 as well as the carriage tachometer signal supplied via line 47 from tachometer 41.

The output of second amplifier 61 is coupled via +1i63 to power amplifier 65, which generates a carriage motor drive signal that is output via +1145.

Referring again to FIG. 1, the fine positioning device
It includes a tracking controller 6T which generates a radial correction signal which is coupled via line 69 to the movable mirror of the optics [17]. Depending on the mode of operation of the device, this signal is transmitted to the reading beam 11.
the beam remains aligned with a selected target track, or the beam incrementally jumps from track to track while approaching the target track. A tracking controller receives the tracking error signal from the function generator 37 via lines 71, 73 .
A plurality of track jump commands are received via 75.

When the system is operating in a manner that is to keep the reading beam 11 aligned with the selected track, the tracking controller 6T actively amplifies the tracking error signal and directs it to the movable mirror of the optical system 17. directly coupled to form a conventional closed-loop tracking servo for controllably aligning the beam with the track. On the other hand, when the device is in search mode and the beam is to be moved incrementally from track to track, the tracking error signal is decoupled from the movable mirror and a predetermined sequence of pulses is coupled in its place.

The tracking controller also outputs a DC tracking error signal which is coupled to the track scan driver 39 via line 49 to adjust the steady state state of the movable mirror by moving the carriage motor 31 in the appropriate orientation. Reduces exposure.

Tracking controller 67 is shown in detail in FIG. This is the inactive circuit or switch circuit 79° amplifier 81
．． and an innate directional bias signal coupled via +W69 to amplify the tracking error signal provided on line 7T and use it to controllably position the movable mirror (FIG. 1) of optical device 17. It includes a power driver 83 that outputs as .

The tracking error signal is
Always tied to inactive circuits. The output of the inactive circuit is coupled via line 85 to the negative input terminal of the amplifier, and the output of this amplifier is coupled via a87 to the power driver.

The power driver outputs a radial correction signal. The signal output from the inactive circuit at 985 is also coupled to a low-pass F wave generator 89 to generate a DC tracking error signal which is coupled via line 49 to track scan driver 39 (FIG. 1).

At the beginning of each search mode, the carriage motor 31
As the read beam 11' moves rapidly towards the target track, the tracking error signal changes in width. FIG. 3 is a partial cross-sectional view of the disk 13 showing three recording tracks, and the open loop tracking error signal is
The center of each track! It can be seen that this is an AC signal with a large amplitude having a zero level at the 1910 position. The inactive circuit T9 then disconnects the tracking error signal from the amplifier 81 to ensure that the device does not attempt to align the read beam 11 with any track as the read beam 11 moves radially toward the target track. do.

In the search mode of operation, whenever the distance between the target truck and the current truck exceeds a predetermined threshold, the carriage motor 3
1 is activated, and whenever this distance does not exceed the dark value, the fine positioning device comprising the movable peg of the optical device 1T is activated.

When the coarse positioner is in operation, a tracking inhibit command is coupled from the function generator 37 to the tracking controller 17' via IIT1. This signal is OR gate 9°
3 and to unfabricated circuit T9 via @95 to decouple the tracking error signal from amplifier 81.

The radial correction signal output by the tracking controller 67 on line 69 therefore has a zero level and the movable mirror is stationary! ＼〇After the reading beam moves to a position tR within a predetermined number of tracks from the target track, function generation Todoroki 37C
1) no longer outputs a speed command to the track scan driver 39 and the carriage motor 31 is no longer driven at a relatively high speed. Then, after a predetermined delay time, the function generator sends the tracking controller 6 via the front NATl.
1, and for this purpose the tracking error signal is again coupled through the tracking controller to controllably align the reading beam 11 with any recording track reached by the beam. Create a tracking-servo loop to After this,
The tracking controller outputs pulses in a predetermined order,
The read beam is incrementally jumped from truck to truck until the read beam reaches the target trunk.

To perform incremental jumps, the tracking controller 6T activates the kick generator 97. It includes a zero-crossing detector, a 99° jumping subtraction counter 101, and a 7-lip, 70-tube N)3. When an incremental jump is to begin, a binary code representing the number of tracks (eg 11 tracks) to be skipped during the next half revolution of the disk 130 is sent from the function generator 3T to 41!73.
is fed into the interlaced subtraction counter. at the same time,
A jump command signal provided from the function generator via 4115 is coupled to a set command input terminal of the 7-lip 70-tub. This sets the Q output signal to a logic one state, and this signal is OR'ed via [1105.

Coupled to gate 93 and then via 4195 to deactivation circuit 79 to open the tracking servo-loop.

The i output signal of the 7 lip-flop 1.03 is coupled to the kick generator 97 via @107. This generator responsively connects #109' to the positive input terminal of amplifier 81.
Outputs a single pulse signal coupled via f@ This pulse signal is coupled via an amplifier and power driver 83 to the movable mirror of the optical device 1T to accelerate the reading beam 11 in the direction of the target track.

After the read beam is accelerated toward the target track by kick generator 97, zero-crossing detector 99 monitors the open-loop tracking error signal (Figure 3b) provided by [77] to determine when the beam intersects the track. It outputs a clock pulse every time it detects the Successive clocks
A pulse is coupled via line 111 to the clock terminal of interlaced subtraction counter 101 and accordingly subtracts the stored count. When the count reaches zero, the counter sends a 1 to the reset instruction terminal of the 7 lip 70 knob 103.
Outputs a reset pulse coupled via i1113.

A reset pulse on line 113 coupled to the set indication terminal of 7 lip-flop 103C1lJ returns the Q output signal to a logic low state, which triggers kick generator 9T, unlike the original pulse. outputs a pulse of opposite polarity, thus reducing the movable mirror to a logic 0.
state, so that the tracking servo loop is no longer deactivated by the deactivation circuit T9, and the loop is reactivated to controllably align the reading beam 11 with the track currently being scanned. It is possible. During this time,
The DC tracking error signal is coupled via line 49t to track scan driver 39 to controllably move carriage motor 31 to reduce deflection of the movable mirror.

Preferably, the reading beam 11 traverses the predetermined number of tracks in a time substantially less than the time required for the disk 13 to rotate half a revolution.

In particular, the beam must traverse the track at a faster rate than the rate at which the radius of the track changes due to disk eccentricity.

Kick generator 97 may include two monostable multivibrators or one-shot circuits.

One is triggered by a positive going change and the other by a negative going change. Additionally, the kick generator may include appropriate gating circuitry to ensure that the successive pulses it generates have the correct polarity to move the reading beam 11 towards the target track. These gate circuits are responsive to forward and reverse commands provided on lines 43e and 43d, respectively.

In another embodiment, the tracking controller 6T radially accelerates and decelerates the reading beam 11 such that the reading beam 11 moves by exactly l track spacing each time. This movement is repeated multiple times (eg, 20 times) during each rotation of the disk until the beam reaches the target track.

FIG. 5 is a schematic diagram showing the radial velocity of the reading beam 11 relative to the disk 13 as a function of distance from the target track. As shown in this figure, if the distance to the target track exceeds a predetermined darkness value Di (for example, 1700 tracks), the coarse positioning device including the carriage motor 31 directs the beam toward the target track at a high speed. drive To this end, the system couples the fast control signal sent via line 43b from function generator 3T to track scanning driver 39, which driver applies a DC drive signal of appropriate magnitude and direction to the carriage motor. Join.

As soon as the beam intersects the distance threshold D1, the function generator 3T terminates the fast control signal and instead generates a medium speed control signal, which is coupled to the track scanning driver 39 via 943m. . At this time, this signal is beam 11
is driven toward the target truck at a medium speed. The beam has a predetermined distance threshold D2 from the target track (e.g. 35
The device continues to drive the beam at this intermediate speed until it has traveled within 0 tracks. When the dark value D2 is reached, the function generator terminates the medium speed control signal and the system allows the carriage motor 31 to decelerate until it stops, as shown at 115. The choice of the particular distance darkness values D1 and D2 is merely a matter of policy and should be determined according to the predetermined characteristics of the system, such as the size and inertia of the carriage motor, the maximum deflection of the movable mirror, etc.

Special considerations are required in devices where the video signal is recorded on the disk 13 with a uniform recording density. Since a variable number of frames are recorded on each trunk, the address of the currently scanned video frame and the address of the target frame correspond exactly to the number of tracks that still have to be traversed. This frame address difference can be suitably converted into an accurate measure of track separation based on the number of frames per track at the current radius. The difference, in the form of \, can be used as a rough estimate of the distance between the tracks. Since the disk must be rotated at an angular velocity that is inversely proportional to the radius of the track being scanned, it is preferred to limit the speed of the carriage motor 31 according to the ability of the system spindle motor 15 to accelerate or decelerate.

When the carriage motor 31 is stopped, the tracking servo loop keeps the read beam 111r aligned with the tracks in the vicinity of the target track. Then, the remaining distance to the target track is incrementally jumped toward the target track. For example, if the beam is 69
If stopped at a track 1 track spacings earlier, the fine positioner causes the beam to incrementally jump 11 track spacings during each of the first six half revolutions of the disk 13; During the next half revolution, it skips three track intervals to finally reach the target track. From the disk, twice during each revolution,
That is, when the read beam scans a portion of the vertical period of the recorded video signal, the updated track address information is reproduced.@ After the read beam 11 finally reaches the target track, the device e.g. Operating in a stop-motion manner, this track can be repeatedly scanned to display the played video signal. If successive tracks are arranged in a spiral pattern, the device must skip one track spacing but one gram in the opposite direction during each rotation of the disk, preferably during a vertical period. Apparatus suitable for performing such truck hopping is described in co-pending U.S. Patent Application Serial No. 130.904.

In another embodiment of the invention, tracking controller 67 causes read beam 11 to jump in only one direction. In this embodiment, the distance thresholds are skewed to either side of the target track such that the carriage motor 31 is always stopped with the beam incident on the track on the appropriate side of the target track. . Furthermore, if the beam is initially a certain number of trunks (say 10 tracks) from the target track on the non-jumping side of the track, then the beam will simply Enter the target track by playing.

FIG. 6 shows the function generator 3 in outputting the speed command and track jumping finger d# when the device is operating in search mode.
2 is a flowchart briefly showing the steps performed by the microprocessor in T. The function generator is a recording disk 13
This process is performed once during every half-rotation of , immediately after the address recovery circuit 29 detects an address signal within the vertical period of the reproduced video signal. In a first step 117, the current track-address signal is subtracted from the address of the target track to generate a number N indicating the number and direction of tracks to the target track. Next, in step 119, this number is compared with N1j-0. If N is equal to O, step 121 instructs the microprocessor to proceed to the replay mode of operation.If the Q number N is greater than 0, step 123 is
A forward direction command is output to c, but if N is smaller than O,
Step 125 outputs a reverse direction command to 1i43d.

When a direction command is output by either step 123 or 125, the program proceeds to step 127 where the number N
The absolute value of INl is compared with the distance darkness value of 1700. If INI exceeds this dark value, step 129
outputs a high speed command signal which is coupled to the track scan drive 6311 via @43b. On the other hand, 1N1 is 170
If the darkness value of 0 is not exceeded, the program proceeds to step 131 where INI is compared to the distance darkness value of 350◎
If IN1 exceeds the dark value, step 133 outputs a medium speed command which is coupled to track scan driver 39 via 1143m. On the other hand, if INI does not exceed the dark value of 350, the program proceeds to step 135 where INI exceeds 11.
If @IN1, which is compared to the darkness value of the distance, exceeds the darkness value of 11, step 137 outputs a jump command coupled to the tracking controller 61 via line 75 while
Outputs a binary code which is coupled to the tracking controller via sT3. This binary code is 0 indicating that the beam should skip 11 track intervals, while INl
does not exceed a threshold of 11, step 139 outputs a skip command on line γ5 and simultaneously sets a binary code of 97 indicating that the beam should skip INI track spacings.
Output to 3. Each command is one of the processes 129, 13
After output by 3, 137 or 139, the program proceeds to the next mode of operation.

As previously mentioned, address register 30 (FIG. 1) stores the address of the most recently detected next track. This addressing is typically updated twice during each rotation of the disk 13, i.e. after the read beam 11 has scanned the portion of the track recording a portion of the vertical period of the video signal. . Because the beam sometimes traverses the track at relatively high speeds, and because the recorded address code typically has about 30 to 46 binary information bits, addresses are often not detected correctly. When this occurs, previous devices typically continued to move the read beam at the same speed as to avoid missing addresses. For this reason,
The beam often overshoots the target track, thus substantially increasing the time required to reach the target track and reproduce the information recorded thereon. Another aspect of the invention provides that the apparatus determines whenever it does not correctly detect a recorded address signal and updates address register 30 with an estimate of the address of the track currently being scanned by reading beam 11. This substantially reduces the tendency for the beam to pass far beyond the target track, thus reducing the average time it takes for the device to reach the target track and reproduce the information recorded thereon. FIG. 7 illustrates the process performed by the address recovery and estimate accumulation circuit 29 (FIG. 1) in updating the address register 30 with the most recently detected current track address or estimated failure of the current address. This is a 7r:l-chart that simply shows the process. In a first step 141, each series of detected data e bits is monitored to determine whether it corresponds to a correctly recovered address signal. Each address signal has approximately 3 bits containing 20 address-pits, 1(K parity bits, and a 12th 7 frame φ bit half at the beginning and half at the end of the signal).
Preferably, it includes three data bits. In particular, step 141 determines whether the frame bit corresponds to a predetermined sign; if it corresponds to 0, the data is assumed to be valid.

If step 141 determines that the series of data bits are valid, the program proceeds to step 143 where the 20 address bits are temporarily stored as the correct address of the track currently being scanned. Thereafter, step 145 uses the detected parity bits to check the parity of the address bits. If the parity is correct, step 147 temporarily stores the address exposed register2.
Update with 0 address bits. If the parity is not correct, the previously stored address bits are discarded and step 149 retains the previous address in address register 30. Ideally, if the program has enough time, it will update the previous address with an estimate of the current address.

If the series of data bits is determined to be invalid by step 141, then the program proceeds to a series of steps that generate an estimate of the current track address, since the address signal was not properly reproduced. Specifically, step 151 determines whether the track scan driver 39 is coupled to a high speed control signal or a medium speed control signal. If a high speed signal is coupled, step 153 sets the variable to 250; if a medium speed signal is coupled, step 15
5 defines D as 50.

Thereafter, step 157 determines whether a forward signal or a reverse signal is coupled to track scan driver 39. If the forward signal is coupled, step 159 adds the value of D (i.e., either 50 or 250) ft to the previously stored address to generate an estimate of the track currently being scanned. . On the other hand, if the reverse signal is coupled, step 151 subtracts the value of D from the previously stored address to generate an estimate of the current track address. Finally, step 163 is the step 159 or 1
61 is stored in address register 30 as the current track address.

This is only when the track address estimation p method described above is being driven toward a row target track at medium or high speeds. Thereafter, the movable mirror in the optical system [17 is not used when the beam is incrementally skipped from track to track. If the address regeneration circuit 29 does not correctly regenerate the address signal at that time, the previously detected address is retained in the register 30.

From the above description, it can be seen that the present invention provides an improved device for moving an information reproducing device at high speed toward a predetermined target track on a rotating recording disk in order to reproduce recorded information. be understood. This device initially translates the information reproduction device fIL radially at a relatively high speed relative to the rotating disk, and then moves the device from track to track multiple times during each rotation of the disk until the target track is reached. By skipping steps incrementally, it operates in a substantially reduced time. If the device is tracked or
If the address or signal is not reproduced correctly, the address of the track currently being scanned is estimated 9 even during the visit, and movement of the information reproducing device is controlled based on this estimate.

[Brief explanation of drawings]

FIG. 1 is a simplified block diagram of a signal reproducing device embodying the present invention, FIG. 2 is a block diagram of a tracking controller used in the device shown in FIG. 1, and FIG. 3 is a block diagram of a tracking controller used in the device shown in FIG. 3 is a partial cross-sectional view of three tracks, showing the open-loop tracking error signal generated while the read beam traverses the tracks in a radial direction; FIG. 4 is a block diagram of a track scanning driver used in the apparatus of FIG. 1; FIG. 5 is a graph showing the radial velocity of the read beam relative to the rotating disk as a function of distance from the target track; and FIG. Figure 7 shows a 70-chart implemented by the apparatus of Figure 1 to controllably vary the radial velocity and direction of the reading beam relative to the disk; Figure 7 shows an address register indicating the address of the track currently being scanned; 2 is a flowchart implemented by the address recovery and estimator 9 circuitry in the apparatus of FIG. Explanation of main symbols 13: Disk 15 Nispindle motor 1T: Scanning device 39 Nidrak scanning driver

Claims (1)

[Scope of Claims] l) In an apparatus for reproducing information from a target track selected from a plurality of substantially circular and concentric recording tracks of a recording disk, means for rotating the disk in a predetermined manner; means for scanning a rotating disk to reproduce recorded information; coarse positioning means for moving the scanning means toward a target track at a predetermined radial velocity relative to the disk; and the coarse positioning means. operative after the scanning means has moved the scanning means into the vicinity of the target track to incrementally move the scanning means across the predetermined plurality of tracks during each revolution of the disk until the target track is reached. and a scanning means which reproduces information recorded on the target track when the target track is reached. 2. In the apparatus according to claim l), the fine positioning means comprises means for radially accelerating the scanning means with respect to the disk in the direction of the target track, and a track traversed by the scanning means. and means for terminating the radial movement of the scanning means relative to the disk after the scanning means has traversed a predetermined plurality of tracks. In the apparatus described in , the scanning means performs an opening operation for each revolution of the disk after the scanning means has traversed a predetermined maximum number of tracks, and comprises the radially accelerating means, the counting means, and 4) In the apparatus according to claim 2), the counting means operates a presettable subtraction number. a counter, means for presetting the counter to a predetermined number, means for detecting when the scanning means traverses the track and for decrementing the counter one count at a time, and counting the counter. means for coupling the termination signal to the means for termination when the signal reaches zero. 5) In the apparatus according to claim l), determining when the scanning means is positioned within a predetermined number of tracks from the target track, and at that time terminating the operation of the coarse positioning means and Apparatus having means for initiating operation of the positioning means. 6)! In the apparatus according to claim 5), the scanning means periodically generates a current track address signal representing the address of the track currently being scanned, and the determining means generates a current track address signal representing the address of the track currently being scanned. - means for comparing the scanning means to a signal representative of the address of the target track to determine whether the scanning means is positioned within a predetermined number of tracks from the target track. 7) In the apparatus according to claim 1), the scanning means includes means for directing light onto the rotating disk to produce a modulated beam having an intensity that varies in accordance with the recorded information. the coarse positioning means includes a motor means for moving the disk radially relative to the optical beam, and the fine positioning means includes beam deflection means for controllably deflecting the beam to adjust its point of incidence on the disk. equipment containing. 8)! In the apparatus as claimed in claim 7), the scanning means generates a tracking error signal representative of a deviation of the light beam from a selected track, and the fine positioning means selectively responds to the tracking error signal. A device that controllably aligns a light beam with a selected track. 9) In a method for reproducing a video signal from a selected target track among a plurality of approximately circular and concentric recording tracks of a rotatable recording disk, the recording disk is rotated in a predetermined shape and an optical device is activated. is used to direct a reading light beam to a selected track of a rotating disk, generate a modulated beam with an intensity modulated by the video signal recorded on the track, and monitor the modulated beam to determine whether the modulated beam is modulated. the optical means is moved radially in the direction of the target track at a relatively high speed with respect to the rotating disk so that the read beam is within a predetermined radial distance of the target track. , the reading beam is moved incrementally across a predetermined plurality of tracks during each rotation of the disk until the radial movement step is completed and the target track is reached. A method comprising the steps of playback of a video signal recorded in a target track by controllably deflecting and subsequent monitoring steps. 10) In the method according to claim 9), the step of controllably deflecting accelerates the read beam radially relative to the disk in the direction of the target track, and the number of tracks traversed by the read beam is and terminating radial movement of the read beam relative to the disk when the beam has traversed a predetermined plurality of tracks. 11) The method of claim 10, wherein said terminating step is performed during each revolution of the disk after the reading beam has traversed a predetermined maximum number of tracks, A method in which the steps of accelerating, counting, and terminating are performed in succession a predetermined number of times until the reading beam reaches the target track. 12. In the method described in claim 10), the counting step includes presetting a predetermined number in a reduced counter, detecting when the reading beam crosses one track, and then The method includes the step of decrementing by one count, and generating a termination signal when the count of the subtractive counter reaches zea, thereby triggering the termination step. 13) In the method described in claim 9), a video signal representing one video frame is recorded on each track of the recording disk, and a unique track address signal is provided in a vertical period, The method further includes the step of determining when the read beam has moved to a position within a predetermined number of tracks from the target track, and then ending the step of radially moving and beginning the step of deflecting.
-'14) In the method according to claim 13), the playback signal is monitored to periodically detect a current track address signal representing the address of the track currently being scanned, and Currently, the process of
A method comprising comparing an address signal with a signal representing an address of a target track to determine whether a read beam is located within a predetermined number of tracks from the target track. 15) The information recorded on each of the plurality of approximately circular and concentric recording tracks of the recording disk includes a unique track address signal, and the disk is rotated in a predetermined shape and the information is recorded in the direction of the target track. The internal device is moved in the radial direction of the disk, and each time the information reproducing device detects a track address signal, the current track address register is updated, and the target address and current track address register are updated.
the method for reproducing information from a selected target track of the plurality of recording tracks, the method comprising: adjusting the radial velocity of the device according to the difference between addresses stored in registers; The method determines when the information reproducing device has not reproduced the recorded track address signal, monitors the radial speed of the information reproducing device with respect to the disk, and uses the monitored radial speed to perform recording. The method includes the steps of: generating an estimate of the address of a track being scanned by an information reproducing device at the time the information reproducing device is being scanned; and updating a current track address register with the address of the estimate. 16) % #f In the method described in claim 15), the information recorded on the recording disk includes a video signal, each track records one video frame, and the target address signal is is provided at successive vertical intervals of the video signal, and the process of generating and determining a reproduction signal corresponding to the information reproduced from the disk by the information reproduction apparatus is performed to generate the data in the successive vertical intervals of the reproduction signal. and evaluating the detected data to determine whether it corresponds to a track address signal.