JPH07107726B2 - Recording / playback device - Google Patents

Description

The present invention relates to a recording / reproducing apparatus for recording / reproducing a video signal, and more particularly to erasing a video signal stored in a track previously formed on a magnetic disk. The present invention relates to improvement of video signal erasing means.

[Prior Art] Conventionally, in the case of erasing a video signal recorded on a track of a magnetic disk in a device of this type, a new erasing signal is superimposed on the video signal of the track to be erased. Thus, the erasing process is executed.

[Problems to be Solved by the Invention] However, in such a conventional apparatus, when the absolute track position at the time of recording and the track position being accessed by the head (recording / reproducing head) at the time of reproduction are misaligned In some cases, even if the erasure is executed, the track deviation cannot be erased, and an unerased portion may be left.

In order to compensate for the track deviation, it is possible to shift the head by the expected track deviation from the track position accessed by the head during playback, and then execute erasing. It is generally difficult to predict, and therefore, when such a method is actually taken, there is a disadvantage that reliable erasing cannot be performed unless a plurality of erasing operations are performed on the same track. There is a problem that it takes time to erase.

Moreover, in the conventional device, when erasing a plurality of continuous tracks from the currently accessed track position,
The operator can arbitrarily monitor only the reproduced video signal of the first track, but the video signals of the tracks to be erased thereafter cannot be monitored if continuous erasure is executed. It had the drawback of being erased.

The present invention has been made in view of the above points, and an object thereof is to shorten the erasing time by enabling a plurality of pieces of video information to be successively erased,
In the case of continuous erasing, the operator can reliably monitor the video information that is erased, prevent erroneous erasure, and keep the video information that is not desired to be erased during continuous erasure. An object of the present invention is to provide a recording / reproducing apparatus for video information.

[Means for Solving the Problems] In order to achieve the above object, the present invention makes it possible to record a plurality of video information on a recording medium and to reproduce a plurality of video information recorded on the recording medium. In the recording / reproducing apparatus, an erasing means for erasing the video information recorded on the recording medium, a setting means for setting continuous erasing of a plurality of video information recorded on the recording medium, and an erasing stop command are inputted. The input means and the video information to be erased is reproduced for a predetermined time in accordance with the setting of the setting means, and the erase of the reproduced video information is executed continuously for each video information to be erased. In addition, when the erase stop command is input within the predetermined time, the control means that does not execute the subsequent erase is provided.

[Operation] According to the present invention, after the video information to be erased is reproduced for a predetermined time according to the setting of the setting means for setting the continuous erasing of a plurality of video information recorded on the recording medium, the reproduced video information is reproduced. Is continuously performed for each image information to be erased, and when the erase stop command is input within the predetermined time, the subsequent erasure is not performed.

Embodiments Embodiments of the present invention will be described in detail below with reference to the drawings.

A. Basic Structure FIG. 1 shows the basic structure of the embodiment of the present invention. In the figure, a is an erasing means for erasing the recording signal recorded on the track of the disc-shaped recording medium, and b is a position where the signal level reproduced by the recording / reproducing head from the recording signal recorded on the track is the maximum. It is a tracking fine adjustment means for performing automatic tracking for moving the head. Reference numeral c denotes an erasing control means, which causes the auto-tracking means b to execute auto-tracking before erasing the recording signal recorded on the track, and moves the head around the track centering on the position of the head after the auto-tracking. Erasing means a for erasing a plurality of times by moving in the circumferential and outer circumferential directions
To execute.

B. Circuit Configuration FIG. 2 shows a circuit configuration of an embodiment of the present invention. In the figure, 1 is a video signal input terminal, 2 is a recording process circuit for performing signal processing for recording a video signal input from the input terminal 1 on a magnetic sheet (magnetic disk sheet) described later, and 3 is a switch. A recording amplifier for amplifying a video signal input via (hereinafter, referred to as SW) and recording it on a magnetic sheet.

Reference numeral 4 is a magnetic head for signal processing and reproduction, 5 is a magnetic sheet as a rotary recording medium, and 6 is a DC for rotating the magnetic sheet 5.
A (direct current) motor, 7 is a magnetic piece mounted on the magnetic sheet 5. Reference numeral 8 is a PG (pulse generator) coil that constitutes a rotation phase detector, and is excited by the magnetic piece 7 once per one rotation of the magnetic sheet 5 to generate a pulse. Reference numeral 9 is a head moving mechanism that moves the magnetic head 4 in the radial direction of the magnetic sheet 5, 10 is a step motor that drives the head moving mechanism 9, and 11 is a step that is controlled by a central processing unit (hereinafter referred to as CPU) described later. This is a driver circuit for driving a motor.

Reference numeral 12 is a reproduction amplifier for amplifying a reproduction signal in which a signal reproduced from the magnetic sheet 5 via the magnetic head 4 is input via SW, and 13 is an output signal from the reproduction amplifier 12, and is a video demodulated from this signal. It is a reproduction process circuit that performs reproduction signal processing for outputting a signal.

Reference numeral 14 is a monitor device for displaying a video signal input via the SW on a display screen. Reference numeral 15 is a CPU (central processing unit) that incorporates a control procedure as shown in FIG. 5, and controls the entire system by switching SW ,, according to this control procedure. An erasing signal generator for generating an erasing signal for erasing the video signal recorded on the sheet 5, 17 is a detection circuit for envelope-detecting the output signal from the regenerative amplifier 12, and 18
Is an A / D converter for A / D (analog-digital) converting the output signal from the detection circuit 17, and the digital output of the A / D converter 18 is supplied to the CPU 15. 19 is a vertical separation circuit (Vsepa circuit) that separates the vertical synchronizing signal from the video signal input from the video signal input terminal 1 and outputs this separated signal to the CPU 15, and 20 is triggered by the output signal from the PG coil 8. , A mono-multi circuit that outputs a pulse to the A / D converter 18.

SW to SW connected to the CPU 15 are manual switches for setting the system operation mode related to the present invention, respectively SW is a recording mode setting, SW is a recording execution,
SW has a function of executing a reproduction mode, SW has a function of setting an erase mode, SW has a function of executing an erase and SW has a function of setting a continuous mode.

C. Recording Mode First, an operation example when recording a video signal on the magnetic sheet 5 will be described.

When a video signal is input from the video signal input terminal 1 and the user turns on the recording mode setting switch, the CPU 15 responds to S
W to contact A, SW to contact D, and SW to contact F
Connect to. At this time, the video signal input from the video signal input terminal 1 is input to the monitor device 14 via the SW and displayed on the monitor.

Next, when the user turns on the recording execution SW, in response to this, the CPU 15 connects the SW to the contact C, and inputs from the video signal input terminal 1 on the magnetic sheet 5 via the SW and the magnetic head 4. The recording of the video signal is executed. At this time, the control timing is configured such that one rotation of the magnetic sheet 5 records one field of the video signal on one track of the magnetic sheet 5, and the timing signal for this is a vertical separation circuit from the input video signal. It is output from the CPU 15 in a fixed phase relationship based on the vertical synchronizing signal separated and output at 19.

The timing of the signal waveform at this time is shown in FIG. In FIG. 3, a is a vertical synchronizing signal output from the vertical separation circuit 19, and b is a switch switching timing signal output from the CPU 15 to the SW. As shown in FIG. 3, the video signal of the next one field after the SW is turned on is recorded. That is, as shown in FIG. 3, before the fall of the vertical synchronizing signal a.
It rises from about 7H (horizontal synchronization clock) and is switched by the timing signal b which becomes H (high) level for one field.
Is connected to the contact c, so that the video signal input terminal 1
The video signal input from the recording process circuit 2 is supplied to the recording amplifier 3 via the SW, amplified, and then supplied to the magnetic head 4 via the SW.
Recording is performed on the track of the magnetic sheet 5 by the magnetic head 4.

C. Playback Mode Next, an operation example in the playback mode will be described.

When the user turns on the reproduction mode execution switch, in response to this, the CPU 15 connects the switch to the contact D and the switch to the contact E. As a result, the signal reproduced from the magnetic sheet 5 by the magnetic head 4 passes through the SW, is amplified by the reproduction amplifier 12 and then input to the reproduction process circuit 13, and the reproduction process circuit 13 demodulates the reproduction signal into a video signal. The processing is performed, and thereafter, it is output and displayed on the display screen of the monitor device 14 via the SW.

Also, during this reproduction, if the track position during recording and the track position during reproduction deviate, the level of the signal reproduced from the magnetic head 4 decreases, and the S / N of the reproduced video signal deteriorates. . For the purpose of preventing this inconvenience, a so-called auto-tracking function of accessing the magnetic head 4 to a position where the magnetic head 4 outputs the maximum reproduction signal will be described.

Here, the recording track of the video signal formed on the magnetic sheet 5 includes, for example, a guard band (protection band),
Although the pitch is 100 μm (track width 60 μm, guard band 40 μm), a slap feed by a step motor is adopted as the head moving mechanism 9 for moving the magnetic head 4 from one track to the next track. For example, the relationship between the head moving mechanism 9 and the step motor 10 is set in advance so that the head feed over a distance of 100 μm is completed with the slap number “12”.

First, when the reproduction mode is set via the CPU 15 by turning on the SW, the reproduction signal output from the reproduction amplifier 12 is detected by the detection circuit 17. An example of the waveform of the detection output of the detection circuit 17 is shown by the symbol C in FIG. In addition, the magnetic piece 7 and
The rotation phase detection pulse d output by the PG coil 8 is converted by the monomulti circuit 20 into a signal pulse shown by e in FIG. Based on the signal pulse e, the output signal c of the detection circuit 17 is analog-digital converted by the A / D converter 18, and the converted digital signal X is input to the CPU 15.

Next, the auto-tracking control of the CPU 15 will be described with reference to the flowchart of FIG.

First, set M = 0 first (step S1),
The A / D conversion value x ₁ sampled at the output timing of the rotation phase detection pulse e shown in FIG. 4 is fetched into the CPU 15 (step S2) and held in an internal memory (not shown) (step S3). Next, the step motor 10 is rotationally driven so as to shift (move) the magnetic head 4 toward the disk inner peripheral direction of the magnetic sheet 5 by one step (step S4). Note that this operation will be referred to as one step up hereinafter. After that, the A / D conversion value x ₂ sampled at the output timing of the rotation phase detection pulse e in FIG.
It is taken into PU15 (step S5). Subsequently, the memory value x ₁ and the fetched value x ₂ are compared to determine whether or not x ₂ ≧ x ₁ (step S6). If x ₂ ≧ x ₁ , it means that the magnetic head 4 is approaching toward the center of the track on the magnetic sheet 5, so after setting M = 1 (step S7), return to step S3 again and The processing of steps S3 to S6 is repeated.

If the magnetic head 4 passes the center of the track on the magnetic sheet 5, x ₂ <x ₁ , so it can be determined that the peak has been exceeded, and then it is determined whether M = 1 (step S
8) When M = 1, it indicates that the magnetic head 4 has approached the center of the track until now, so the magnetic head 4 is returned to the outside by one step via the step motor 10 (step S9). Since the returning position is considered to be approximately the center of the track, this control ends. Note that this returning operation will be referred to as one step down.

On the other hand, when the _first determination of x ₂ ≧ x ₁ in step S6 is a negative determination, that is, the magnetic head 4 causes the magnetic sheet 5 to move.
When the track is separated from the center of the track No., M = 0 is still maintained. Therefore, the judgment of M = 1 in the next step S8 is also a negative judgment, and this time, the above-mentioned fetched value x ₂ is stored in the internal memory. (Step S10). Then, this time, the magnetic head 4 is returned one step toward the outer circumference of the magnetic sheet 5 (step S11). Next, the A / D conversion value x ₃
Captured inside (step S12), this captured value x ₃
Is compared with the memory value x ₂ to determine whether or not x ₃ ≧ x ₂ (step S13). Then, in the normal case, x ₃ ≧ x ₂ , so it is known that the magnetic head 4 is approaching the track center of the magnetic sheet 5, and then M = 1 is set (step S14), and the process returns to step S10. When returning and repeating this operation procedure (steps S10 to S14), the magnetic head 4 sometime exceeds the center of the track, and x ₃ <x ₂ . In that case, the process proceeds from step S13 to step S15, and in step S15, M =
Whether it is 1 or not is determined, but in this case, M = 1, so an affirmative determination is made and the magnetic head 4 is set to 1
The step is returned to the inner peripheral side of the magnetic sheet 5, and the returned position is substantially the track center, so this control is ended.

On the other hand, if x ₃ <x ₂ when the A / D converted values x ₃ and x ₂ are first compared in step S13, it is considered that some abnormality occurred in data detection. In this case, the determination of M = 1 in step S15 is a negative determination, so the process returns to step S3 and the above sequence processing is repeated.

As described above, the CPU 15 is in the playback mode,
The position of the magnetic head 4 is controlled so that the level of the reproduction signal is always maximized.

D.1 Track Erase Mode Next, an operation example in the erase mode will be described with reference to the flowchart of FIG.

First, when the user turns on the erase mode setting switch in the reproduction mode after executing the above-described auto tracking in the reproduction mode (step S21),
The erase mode is set, and an LED (light emitting diode) not shown lights up (step S22) to notify the user (operator) that the erase mode has been set. When the user turns on the erase execution switch in this state (step S2
6) The information recorded on the track of the magnetic sheet 5 is erased.

Further, this operation will be described in detail. Erase as above
When the SW is turned on, the CPU 15 connects the SW to the contact B and the SW to the contact C (step S28). Next, when the CPU 15 outputs the erase start signal to the erase signal generator 16, the erase signal generator 16 outputs an attenuated signal erase signal (oscillation time of about 1 sec) as shown in FIG. 6 to the recording amplifier 3 and SW. The data is recorded on the magnetic sheet 5 by the magnetic head 4 via the magnetic head 4, so that the video signal on the track is erased.

At that time, before actually performing the erasing, that is, before the CPU 15 outputs the erasing start signal to the erasing signal generator 16, the CPU 15 drives the driver circuit 11, and the step motor 10 and the head moving mechanism 9 cause the magnetic head 4 to move. Step motor 10 of 1
After moving in the step-up direction (inner circumferential direction of the magnetic sheet 5) by the step (step S29), an erase signal is generated from the erase signal generator 16 (step S30).

When the attenuation of the preset erase signal is completed, the CPU 15 then drives the driver circuit 11 to move the magnetic head 4 in the step-down direction (outer peripheral direction of the magnetic sheet 5) by two steps (step S31). ), The erase signal is generated again from the erase signal generator 16 for a preset time, and the erase is executed (step S3).
2).

After that, the CPU 15 drives the driver circuit 11 again to move the magnetic head 4 in the step-up direction by one step.
Is moved (step S33). Here, the magnetic head 4
Has returned to the first track position and the entire erase sequence has been completed.

When erasing is performed from the reproduction mode, the auto-tracking as shown in FIG. 5 is performed as described above, that is, the position of the magnetic head 4 is set to be almost the same as the position of the magnetic head 4 at the time of recording. After that, the magnetic head 4 is moved for one step before and after the set position to execute the erasing operation twice, so that the video signal on the track can be surely erased, and at the time of recording and reproduction. The video signal recorded on the magnetic sheet 5 is erased without the displacement of the position of the magnetic head 4. Further, when the track width of the magnetic head 4 is different at the time of recording and at the time of reproducing, for example, when the track width at the time of recording is larger than that at the time of reproducing, erasing is executed without any problem.

E. Continuous erasing mode Next, the operation in the case of continuous erasing in which the video signals recorded on the magnetic sheet 5 are continuously erased will be described.

First, after the auto-tracking shown in FIG. 4, the erase mode setting switch shown in FIG. 2 is turned on (step S21), and the continuous mode setting switch is turned on (step S34), the continuous erase mode is set. When the erase execution switch is turned ON in this state (step S35), the erase operation is executed as follows for the continuous tracks on the magnetic sheet 5.

First, the one-track erasing operation indicated by the broken line in FIG. 7 described in detail in the above section D is performed (step S36). Then C
The PU 15 connects the SW to the contact D (step S37), drives the driver circuit 11 to rotate the step motor 10, and moves the magnetic head 4 to the step motor 10 via the head moving mechanism 9.
12 steps are moved in the step-up direction (step S38). Here, one track has 12 steps. As a result, the magnetic head 4 is moved to the inner peripheral side of the magnetic sheet 5 by one track, and the auto-tracking operation shown in FIG. 4 is performed again (step S39). Is set to the position where the reproduction output is maximized. After that, for example, after holding that state for about 1 second (step S40), the CPU 15
Connects SW to contact C and executes the one-track erasing operation similar to step 36 described above (step S42).

These operations shown in steps S37 to S42 are performed until the magnetic head 4 finishes erasing the innermost track (step S4
3), repeat. However, when the erase mode setting switch is turned off during the above-mentioned continuous erase (step S41), the continuous erase is stopped at that point. That is, the erased video signal is executed even in the case of continuous erasing (step S42).
Prior to this, the output will be displayed on the monitor device 14 for about 1 second by auto-tracking (step S4
0), the operator can confirm the video signal to be erased. For example, if the video signal that you do not want to erase is a monitor device
When it is displayed in 14, turn off the SW (step S
41), continuous erasing will be stopped, and there is almost no concern about erroneous erasing.

In the recording mode, if the erase mode setting switch is turned ON and the erase mode is set (step S21),
First, the CPU 15 connects the SW to the contact D and connects the SW to the contact E (step S24), and then the above-mentioned auto-tracking is performed (step S25) to complete the preparation for erasing.
Next, if the SW is turned on (step S26), the reliable erasure in the 1-track erasing mode as described above becomes possible (steps S28 to S33). On the other hand, after turning on the SW, the SW is turned on.
When turned on (steps S34 and S35), reliable erasure in the continuous step mode is possible (steps S36 to S43).

The amount of movement of the magnetic head 4 that moves in one step of the step motor 10 is as described above. However, it is needless to say that the value may be further increased depending on the error of the track position and the error of the track width which are expected based on the experimental value of the design structure, experience, and the like.

If the amount of movement of the magnetic head 4 that moves in one step of the step motor 10 is smaller than the expected track position error and track width error, the track movement amount during execution of erasure is set to 2 instead of 1 step. It should be set to a larger value than the step.

Furthermore, the monitor display time of the reproduced video signal at the time of executing the continuous erasing is not limited to 1 second as in the present embodiment, and there is no problem as long as the operator can sufficiently confirm the video signal. It should be noted that the present invention also includes one in which the reproduction mode is automatically switched for a predetermined time when erasing only one field.
Further, the disk as the medium is not limited to the magnetic one.

As described above, according to the above-described embodiment of the present invention, the tracking fine adjustment is executed and the head position is finely adjusted prior to the execution of the erasing, and then the predetermined erasing operation is performed based on the moved position. Since it is being executed, even if the head position is misaligned during recording and playback, or when the track width during recording is larger than the track width of the head during playback, reliable erasure is performed without erasure. The effect is obtained.

Further, in the above-described embodiment of the present invention, the tracking fine adjustment is executed at the time of erasing, and the reproduced video signal of, for example, about 1 second is output to the monitor device.
Since the video signal to be erased next can be surely confirmed, it is possible to surely perform the erase.

EFFECTS OF THE INVENTION As described above, according to the present invention, since continuous erasing can be performed, the erasing time can be shortened and
At the time of continuous erasing, after reproducing the video information to be erased for a predetermined time, erasing the reproduced video information is continuously performed for each video information to be erased and within the predetermined time. Since the subsequent erasure is not executed when the erasure stop command is input to, it is possible to obtain the effect that the image information that is not desired to be erased can be left as it is during continuous erasure.

[Brief description of drawings]

FIG. 1 is a block diagram showing a basic configuration of an embodiment of the present invention, FIG. 2 is a block diagram showing a circuit configuration of an embodiment of the present invention, and FIG. 3 is a signal during a recording operation of the embodiment of the present invention shown in FIG. 4 is a time chart showing the timing of signals, FIG. 4 is a time chart showing the timing of signals during auto-tracking according to the embodiment of the present invention shown in FIG. 2, and FIG. 5 is a control operation of the auto-tracking according to the embodiment of the present invention shown in FIG. 6 is a waveform diagram showing the waveform example of the erase signal of the embodiment of the present invention in FIG. 2, and FIG. 7 is a flowchart showing the control operation during the erase operation of the embodiment of the present invention in FIG. is there. 1 ... video signal input terminal, 2 ... recording process circuit, 3 ... recording amplifier, 4 ... magnetic head, 5 ... magnetic sheet, 6 ... DC motor, 7 ... magnetic piece, 8 ... PG coil (Rotation phase detector), 9 ... Head moving mechanism, 10 ... Step motor, 11 ... Driver circuit, 12 ... Regeneration amplifier, 13 ... Regeneration process circuit, 14 ... Monitor circuit, 15 ... CPU, 16 …… Delete signal generator, 17 …… Detection circuit, 18 …… A / D converter, 19 …… Vertical separation circuit, 20 …… Monomulti circuit, SW …… Record / erase selector switch, SW …… Record / Play selector switch, SW …… Record mode setting switch, SW …… Record execution switch, SW …… Play mode execution switch, SW …… Delete mode setting switch, SW …… Delete execution switch, SW …… Continuous mode setting switch , SW ... Monitor selector switch.

Claims (1)

[Claims] 1. A recording / reproducing apparatus capable of recording a plurality of video information on a recording medium and reproducing the plurality of video information recorded on the recording medium, wherein the video information recorded on the recording medium is Erasing means for erasing, setting means for setting continuous erasing of a plurality of video information recorded on the recording medium, input means for inputting an erasing stop command, and erasing according to the setting of the setting means After the video information to be erased is reproduced for a predetermined time, the reproduction of the reproduced video information is continuously performed for each of the video information to be erased, and an erase stop command is input within the predetermined time. A recording / reproducing apparatus comprising: a control unit that does not execute subsequent erasure in the event of an accident.