JPH0756738B2 - How to play - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for improving scannability in a playback device capable of random access.

<Prior Art> Conventionally, for example, random media using a medium such as a magnetic disk
Various accessible playback devices have been considered.

In such an apparatus, the information to be recorded in each track is often independent of each other, and the information of each track is often erased independently.

Therefore, conventionally, the presence or absence of the recording of the next track is detected every time the recording and the reproduction of one track are completed, and the next unrecorded track is recorded when recording and the next recording is recorded when reproducing. Techniques were used to jump trucks until they found one. Therefore, not only does the access time increase as the number of jumps to be jumped increases, but in the case where only the last track is vacant after all, or when there are no vacant tracks, the detection time and shift time during that period are completely eliminated. It has the drawback of being meaningless.

When a recording medium such as a magnetic disk for eliminating such a defect is mounted on the recording / reproducing apparatus, all the tracks on the recording medium are sequentially scanned by the head, and the output of the head obtained during the scanning is detected. Which track is an empty track and which track is a recorded track, and shifts the head to an empty track when recording is performed based on the information of the stored empty track and the recorded track. A technique has been filed by the applicant as JP-A-59-71102.

<Problems to be Solved by the Invention> However, in the above-mentioned technique by the applicant, in order to control the head position which is good for recording on the recording medium, all of the recording medium on the recording medium to be mounted when the magnetic disk is mounted. The scanning of the tracks is sequentially performed from the first track to the final track, and when the scanning up to the final track is completed, the head is automatically returned to the empty track. Therefore, when reproducing the tracks on the recording medium, the head must be returned to the initial position at the time of reproduction when the scanning of all the tracks is completed, until the reproducing operation is performed after the recording medium is mounted. There was a drawback that the operability was not good because of the large time lag.
The present invention aims to eliminate such drawbacks, shorten the time lag until the playback operation is performed, and improve the operability. [Method for Solving Problems] The invention is a reproducing method in which a recording medium is loaded, the reproducing head is moved in a predetermined direction with respect to the loaded recording medium, and the recorded information is reproduced at the moved position. When the loading is detected, and when the loading of the recording medium is detected, the end position (the position corresponding to the first track in the embodiment) opposite to the end position on the recording medium (corresponding to the first track) is reproduced. Similarly, from the 50th track), the reproducing head is sequentially scanned in the opposite direction to the predetermined direction, and the presence or absence of recording at the reproducing position on the recording medium is determined and stored (also STEP8 to STEP10),
When it is determined whether or not there is recording at each reproduction position on the recording medium, the reproduction head is positioned at the initial position for reproduction (also a flow branching from STEP11 to STEP14), and the given reproduction is performed. Instruction (also STEP1
6) and the memory (also STEP17), the reproducing head is moved (also STEP18) to reproduce the recorded information on the storage medium.

<Embodiment> FIG. 1 shows a block diagram of a reproducing apparatus according to an embodiment of the present invention. In FIG. 1, 1 is a magnetic sheet in which the number of recording / reproducing tracks of image signals, track pitch, and track position are previously determined, 2 is a DC motor for rotating the magnetic sheet at a constant speed, 3 is a magnetic head, and 4 is a magnetic head. Three
The moving mechanism 5 for moving the magnetic head 3 for moving the track formed on the magnetic sheet 1 so as to access the magnetic sheet 1 is formed by the magnetic head moving mechanism 4 so as to turn on when the magnetic head accesses the innermost track. Switch,
6 is a reproduction amplifier for amplifying the signal detected by the magnetic head 3, 7 is the level of the output signal from the reproduction amplifier 6, and outputs an "H" level signal when the level is higher than a certain level. A level detecting section, 8 is a driver for driving the magnetic head moving mechanism 4, 9 is an output signal of the innermost circumferential position detecting switch 5 and the level detecting 7 and an output signal of a switch 11 formed by a photo coupler, and A processor (hereinafter referred to as CPU) 10 that controls the driver 8 that drives the magnetic head moving mechanism 4 and controls the rotation of the DC motor 2 is a memory that allows the CPU 9 to read and write data. Reference numeral 11 is a photocoupler for detecting that the magnetic sheet 3 is inserted, and is a switch that operates by blocking the light when the magnetic sheet is inserted.

12 is a reproduction process that demodulates the output signal of the reproduction amplifier and performs processing for reproducing the video signal, and 13 is a reproduction process 12
A video amplifier that amplifies the reproduced video signal output by, 14 is a miute circuit that mutes the output from the video amplifier 13 based on the signal of the CPU 9, and 15 is the video amplifier 13,
A monitor device for monitoring the output through the miute circuit 14. Reference numeral 16 is a power supply circuit that generates a power supply voltage VDD, and 17 is a power supply switch. Reference numeral 18 is a switch that is turned on from off when an operation for taking out the magnetic sheet is performed. Reference numeral 19 is a switch for starting the reproducing operation, and when manually operated and turned on, the reproducing operation is started. 20 and 21 are switches for deciding which track is reproduced when the reproduction operation is performed.
The count value of the up-down counter 22 is incremented by 1 each time the switch is turned on once, and the count value of the up-down counter 22 is decremented by 1 each time the switch 21 is turned on. 22 is a switch 21,20
It is an up-down counter for sending the CPU9 the track number set by. Reference numeral 23 is a display for displaying the recording track.

The number of tracks forming the track row formed on the magnetic sheet 1 of the present embodiment was 50, and the tracks formed on the outermost periphery of the magnetic sheet were formed on the first track and the innermost periphery. The track is the 50th track.
Further, a case where the magnetic head moves to the inner peripheral side of the magnetic sheet is called a track up, and a case where it moves to the outer peripheral side is called a track down.

Next, the operation of the embodiment shown in FIG. 1 will be described using the flow chart shown in FIG.

First, the operation when the apparatus is powered on will be described with reference to FIGS. 1 and 2. When a power supply SW (not shown in FIG. 1) is turned on, this device operates according to the flow chart shown in FIG. 2. However, when the power switch 17 of STEP 1 is turned on in the flow chart shown in FIG. The CPU 9 determines whether or not the magnetic sheet 1 is inserted by the output signal of the photocoupler switch 11 (STEP
2). When the magnetic sheet 1 is not inserted, the CPU 9 reads the output signal of SW5 and determines whether SW5 is on (STEP4). If SW5 is not on, that is, if magnetic head 3 has not reached the innermost circumference, CPU9
Controls the driver 8 so that the head feeding mechanism 4
To move the magnetic head for one track to the inner circumference side (STEP 5). After repeating this operation until the SW is turned on, the operation moves to STEP6, and in STEP6, the CPU 9 sets the address N of the memory 10 in preparation for writing the data in the memory 10.
Set to 50. Next, the CPU 9 judges whether the DC motor 2 is rotating at a constant speed (STEP7), and if it is not rotating at a constant speed, S
It will branch to TEP92. In other words, when the magnetic sheet is not turned on when the power is turned on, the flow skips STEP2 to STEP3 and advances to STEP4, so the DC motor 2 is not rotating at a constant speed. In this case, STEP7 branches to STEP22, and the magnetic head 3 It means that it is waiting with 50 tracks accessed. Next, power supply with the magnetic sheet 1 inserted
The operation when the SW17 is turned on will be described. In such a case, when the power SW17 is turned on, the magnetic sheet is included, so the flow proceeds from STEP2 to STEP3, and the DC motor 2 causes the CPU9
Is controlled to rotate at a constant speed. Next, STEP4, STEP
After detecting the ON state of SW5 by 5, that is, after moving the head 3 until the magnetic head 3 turns on the switch 5, ST
When EP7 detects that the DC motor is rotating at a constant speed, the flow moves to STEP8. Turn on the power and turn the head 3
The same applies when the magnetic sheet is inserted after the 50th track is accessed. On the other hand, the signal recorded in 50 tracks on the magnetic sheet 1 reproduced by the magnetic head 3 is input to the reproduction amplifier 6, amplified here, and then input to the level detector 7.

The level detector 7 detects whether or not the level of the reproduction signal is higher than a predetermined level. When the level detector 7 is larger, the level detector 7 outputs an “H” level signal to the CPU 9, and when it is smaller, “ Outputs L "level signal to CPU9. STEP7
When the DC motor 2 is rotating at, the CPU 9 reads the output signal of the level detector 7 at STEP8. If the signal read here is at H level, the memory
The "H" level is set as data at address 10 (N = 50), and if it is at L level, the "L" level is set as data (STEPs 9 and 10). Next, in STEP 11, it is judged whether the memory address N is equal to 1 or not.
U9 drives the driver 8 to operate the head moving mechanism 4 to move the magnetic head for one track to the outer peripheral side (ST
EP12). Here, since the magnetic head 3 is accessing the 50th track, the memory address is not equal to 1, so STEP
The flow proceeds from 10 to STEP 11. Next, N-1 is entered as the memory address N, the process branches to STEP8, and the above-described operation is repeated. Since the magnetic head 3 was accessed at the 50th track first, the above operation is repeated 50 times, and when N becomes equal to 1, the flow moves from STEP11 to STEP14 to complete the initial setting operation. , The recording track will be displayed.

Next, details of the reproducing operation performed after STEP 14 in FIG. 2 will be described with reference to FIG. FIG. 3 is a flow chart of the CPU 9 performed in the reproducing operation.

When the flow reaches STEP 14 in FIG. 2 and the head 3 is accessed at the initial position of the reproducing operation, it is determined whether or not the reproducing operation is instructed as shown in STEP 15,
When instructed, the flow proceeds to STEP16. Whether or not the start of the reproducing operation is instructed is determined by the switch 19 shown in FIG.
Is on, i.e. connected to switch 19
This is performed by detecting whether the input port of the CPU 9 is H level or L level. At STEP 16, the reproduction track number set by the switches 20 and 21 is read from the up-down counter 22, the information of the memory 10 corresponding to the number is read, and then at STEP 17, it is determined whether or not the track of the number is recorded. judge. If the track of the number set here is recorded, the flow proceeds to STEP 18 if it is not recorded to STEP 18.

In STEP 18, the head 3 first accesses the track with the track number set by the switches 20 and 21,
The signal of the head 3 is the reproduction process circuit 12, the video amplifier 13
Is output to the miute circuit 14 via. Here, since the start of the miute operation is not instructed by the miute circuit 14 and the CPU 9, the output of the video amplifier 13 is transmitted to the monitor device 15. Therefore, the signal of the head 3 is reproduced on the monitor device 15. Also, in STEP 19, the miute circuit 14
Since U9 is instructed to perform the miute operation, it is possible to prevent the display by the white noise on the monitor device 15.

As described above, the initial setting operation is completed and the magnetic head 3 is
When all the tracks are sequentially scanned from 50 tracks and the presence or absence of recording is stored, the magnetic head 3 accesses the initial position of the reproducing operation, that is, the first track. Therefore, the preparation time of the reproducing operation is shortened as compared with the conventional method in which the magnetic head 3 sequentially scans all tracks from the first track to the 50th track, and then the magnetic head 3 is accessed to the initial position of the reproducing operation. You can

Next, with reference to FIG.
A case will be described in which the magnetic sheet take-out operation is performed while executing STEP 7 to STEP 14 of the flow shown in the figure and the flow chart shown in FIG.

When the magnetic sheet is taken out in this way, the information regarding the presence / absence of recording of all the tracks stored in the memory 10 shown in FIG. 1 does not always correspond to the track of the magnetic sheet to be mounted next. Therefore, it is necessary to detect the presence / absence of recording of all tracks again. Therefore, in this embodiment described below, the magnetic head 3 is provided at the end portion on the side opposite to the initial position of the reproducing operation in order to detect the presence / absence of recording of all tracks, which is performed again when the magnetic sheet is taken out. Is accessed, and the preparation period for the next playback operation is shortened as much as possible.

FIG. 4 is a flow that is time-divided with the flow shown in FIGS. 2 and 3, and uses the interrupt mode of the CPU 9. STEP 21 is a step for determining whether or not the switch 18 shown in FIG. 1 which is turned on when the operation for taking out the magnetic sheet is performed is turned on. In such step 21, the switch 18 is turned on. If it is detected, the process proceeds to STEP22. STEP 22 is a step for causing a magnetic sheet eject mechanism (not shown) to take out the magnetic sheet. Next, in STEP23, the drive of the DC motor 2 is stopped, the flow branches to STEP4 shown in FIG. 2, and as described above, the flow of STEP4 and STEP5 is repeated to access the magnetic head to the 50th track and the flow to ST.
EP7. Since the drive of the CD motor 2 is stopped in STEP23, the flow branches from STEP7 to STEP2.
When the flow from EP7 to STEP2 is repeated and the insertion of the magnetic sheet is detected by the photocoupler 11, the above-described flow is executed.

In this embodiment, the initial position of the head in the reproducing operation is the first track, but the 52nd track (Cue track), that is, the control signal for the reproduction order method of the image information recorded from the first track to the 50th track is The recorded track may be set as the initial position of the head 3 in the reproducing operation. In such a case, instead of the switch 5 shown in FIG. 1, a switch that switches the state when the head accesses the first track is provided, and the contents of STEP 5 in the flow shown in FIG. 2 are set to 1 track DOWN, S
The memory address set in TEP6 and STEP12 is N = 1
Then, STEP11 may be a step for determining whether N = 50, and STEP13 may be a step for performing an operation by setting N = N + 1.

Although a magnetic sheet is used as the recording medium in this embodiment, a recording medium such as an optical disk or a magneto-optical disk may be used, and in such a case, an optical head may be used as the head.

〔The invention's effect〕

As described above, according to the present invention, when the loading of the recording medium is detected, the predetermined direction is set from the end position opposite to the reproduction initial position of the end part on the recording medium. When the presence or absence of recording at each reproduction position on the recording medium is determined by recording the presence or absence of recording at the reproduction position on the recording medium by sequentially scanning the reproduction head in the reverse direction. In addition, since the reproducing head is positioned at the reproducing initial position, the time lag of the reproducing operation start until the reproducing head is positioned at the reproducing initial position and the recording state on the recording medium is determined is small. Yes, the reproduction can be performed immediately, and since the reproducing head is moved based on the given reproduction instruction and the storage, there is no need to reproduce an area on the recording medium where no information is recorded. It is possible to prevent the Do not reproducing operation.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, and FIGS. 2 to 4 are flow charts of the CPU 9 shown in FIG. 3 ... Magnetic head 9 ... CPU

Claims (1)

[Claims] 1. A reproducing method in which a recording medium is loaded, a reproducing head is moved in a predetermined direction with respect to the loaded recording medium, and recorded information is reproduced at the moved position. When the loading of the recording medium is detected, and when the loading of the recording medium is detected, from the end position opposite to the initial position for reproduction of the end portion on the recording medium, the direction opposite to the predetermined direction When the presence or absence of recording at the reproduction position on the recording medium is determined and stored, and the presence or absence of recording at each reproduction position on the recording medium is determined. The reproducing head is positioned at an initial position for reproduction, and the reproducing head is moved based on a given reproduction instruction and the stored information to reproduce recorded information on the recording medium. How to play.