JPH04153943A - Helical scanning type magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To realize a long-time standby state by reducing a tape tension value compared to recording or reproducing time under the state of standby and running the tape by a prescribed amount each time duration for the standby state reaches a prescribed time. CONSTITUTION:At the time of standby mode, a system controller 27 instructs a command realizing the standby state to each control system. Accordingly, a drum control system synchronizes the synchronization signal of an input video signal and rotates a drum 1, and a capstan control system stops a capstan 8, and a reel control system controls both reels 16 and 20 so that tape tension can be the prescribed low tension. When the standby state lasts over the prescribed period of time, the duration of the standby time is measured by a timer circuit 28 and a command for running the tape is outputted to a capstan control circuit 13 each time the prescribed time is reached. Thus, the long-time standby state can be realized.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a standby function and tape tension control in a standby state in a helical scanning type magnetic recording/reproducing device.

[Conventional technology]

In helical scanning magnetic recording and reproducing devices such as VTRs, the rise time of the drum carrying the magnetic head is much longer than the rise time of the tape running.
Some devices have a standby function to enable quick and timely recording. This standby function rotates the drum at a predetermined rotational speed synchronized with a recording input signal such as a video signal while the tape is stopped. Therefore, when starting recording from the standby state, recording starts with a delay equal to the start-up time of tape running, so compared to starting recording from a stop state, recording can be started in a shorter time by the start-up time of drum rotation, resulting in faster recording. Moreover, timely recording can be realized. However, in this standby state, since the tape is stopped, the magnetic head always scans the same part of the tape, and if this standby state continues for a long time, the magnetic layer of the tape may peel off or, in the worst case, In some cases, the tape may have to be cut.

Therefore, in order to prevent these tapes from being damaged, if a certain period of time (about a few minutes) has elapsed in standby mode, either cancel standby mode and shift to stop mode, or
Alternatively, for example, a tape tension control means as disclosed in Japanese Patent Application Laid-Open No. 6476477 is used to lower the tape tension in the standby state compared to during normal recording and reproduction.

[Problem to be solved by the invention]

However, although canceling the standby state after a certain period of time described above is fine if the approximate recording start time is known, it becomes extremely inconvenient if the recording start time changes over a range of several hours. turn into. In addition, in the method of lowering the tape tension in standby mode, the tension is controlled while the tape is stopped, so the influence of friction in the tape running system becomes large, and the precision tape tension of the part in contact with the drum surface increases. Difficult to control. However, if the tape tension in the standby state is set to a very low value, the tape tension will drop more than necessary due to variations in the reel motor characteristics and control circuit characteristics, causing the tape to fall off from the original tape running system. I wake up.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a helical scanning type magnetic recording/reproducing device that is easy to use and can remain in a standby state for a long time without damaging the tape.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a tape running control means that wraps a tape around a drum at a predetermined angle, runs, stops, and advances the tape frame by frame according to commands from a system controller, and controls the tape tension to a predetermined value. A tape tension control means and a timer means for measuring the duration of the standby state are provided, and in the standby state, the tape tension value is lowered compared to that during normal recording or playback, and the duration of the standby state reaches a predetermined time. Each time, the tape was run a predetermined distance in the forward or reverse direction.

Furthermore, a level detection means for the reproduction signal detected by the magnetic head is provided, so that in the standby state when a recorded tape is loaded, the reproduction signal level is reduced by a predetermined amount compared to the normal reproduction level. The tape tension can now be controlled.

[Effect]

Since the tape tension control means lowers the tape tension in the standby state, damage to the tape due to head scanning can be prevented within a certain period of time. The timer means for measuring the duration of the standby state and the tape running control means measure the duration of the standby state and move the tape in the forward direction or forward direction within the above-mentioned low tape tension state without exceeding the permissible time for tape damage. Since the tape is run a predetermined distance in the opposite direction, the standby state can be continued for a long time without damaging the tape.

Furthermore, a playback signal level detection time is provided, and in standby mode when a recorded tape is loaded, the tape tension is controlled so that the playback level is below a predetermined value, so the tape tension is controlled so that the playback level is less than a predetermined value. It is possible to accurately control the tension of the part of the tape that is scanned by the head, and it is possible to increase the reliability of preventing damage to the tape.

〔Example〕

Hereinafter, one embodiment of the present invention will be described using the drawings from FIG. 1 onwards. FIG. 1 is a block diagram of a VTR having a standby function to which the present invention is applied.

In Figure 1, ■ is a drum, 2 is a drum motor, and 3a
, 3b is a magnetic head, 4 is an FG sensor (FG:Fr
Abbreviation for "Equency Generator", which represents a pulse proportional to the rotation of the motor. ) 5 is a drum rotation phase detector, 6 is a drum control circuit, 7 is a drum motor driver, 8 is a capstan, 9 is a capstan motor,
10 is an FG sensor, 11 is a pinch roller, 12 is a control signal head, 13 is a capstan control circuit, 14
is a capstan motor driver, 15 is a supply reel, 1
6 is a supply reel motor, 17 is an FG sensor, 18 is a motor driver, 19 is a take-up reel, 20 is a take-up reel motor, 21 is an FG sensor, 22 is a motor driver, 23 is a reel control circuit, 24 is a potentiometer, 25 26 is a spring, 26 is an arm, 27 is a system controller, 28 is a timer, 29 is an amplifier and switch, 30 is a video/audio processing circuit, 31 and 32 are video and audio input/output terminals, and 33 is a magnetic tape.

First, the recording and reproducing operations of the VTR shown in FIG. 1 will be explained. The video and audio signals supplied through the input/output terminals 31 and 32 during recording are sent to the video and audio processing circuit 3.
At 0, the signal is converted into a signal format suitable for magnetic recording and supplied to the amplifier & switch 29. The amplifier & switch 29 amplifies the recording signal to the optimum recording level, and then amplifies the recording signal to the magnetic head 3.
Switch to a or 3b and supply. At this time drum 1
The zero rotation control section is performed by the drum control circuit 6, the drum motor 2, and the drum motor driver 7 according to a command Cd from the system controller 27, and the speed and phase are controlled. Speed control is performed by feeding back the difference between the period of the DFG signal (drum FG) generated by the FG sensor 4 at a frequency proportional to the rotational speed of the drum and the DFG signal period at the target speed to the drum motor 2 via the motor driver 7. It will be done as follows. Phase control is performed so that the drum rotational phase detection signal DTP generated by the drum rotational phase detector 5 and the reference signal REF synchronized with the synchronization signal of the input video signal supplied from the video/audio processing circuit 30 have a predetermined phase. This is done by feeding back the phase error amount to the drum motor 2 via the motor driver 7 so as to maintain the relationship.

On the other hand, tape running control at this time is performed by a capstan control system. The rotation control of the capstan 8 is performed by the system controller 2 using a capstan control circuit 13, a capstan motor 9, and a capstan motor driver 14.
The speed and phase are controlled according to the command Cc from 7. Speed control is performed using a CFG signal (
Capstan FG) period and CFG at target speed
This is done by feeding back the difference from the signal period to the capstan motor 9 via the motor driver 14. Phase control is C
The phase error is calculated by the motor so that the signal obtained by dividing the FG signal at a predetermined frequency division rate and the reference signal REF synchronized with the synchronization signal of the input video signal supplied from the video/audio processing circuit 30 have a predetermined phase relationship. This is done by returning to the capstan motor 9 via the driver 14. At this time, the capstan control circuit 13 generates a CTL signal (control signal) used for tracking control during reproduction in synchronization with the reference signal, and supplies it to the CTL head 12. C
The TL head 12 records two CTL signals on a CTL track provided in the longitudinal direction of the tape 33. The above tape running by the capstan is performed by the pinch roller 11 sandwiching the magnetic tape 33 and pressing it against the capstan 8. Tape tension control during tape running in the capstan drive described above is performed by the reel control system. The reel control system includes a supply reel motor 16 and its driver 18, and a take-up reel motor 20 and its driver 2.
2, and a tension sensor consisting of a reel control circuit 23, a potentiometer 24, a spring 25, and an arm 26. First, the take-up retention control of the take-up reel is such that the reel control circuit 23 sends a control signal according to the winding diameter of the take-up reel so that the tape tension between the capstan 8 and the take-up reel is a constant value. This is done by supplying the take-up reel motor 20 via the driver 22. On the other hand, supply reel pack tension control controls the tension value of the tape in contact with the drum to a predetermined value.
This ensures that the head 3 touches the tape 33. Therefore, the reel control circuit 23 controls the supply reel 1
A control signal according to the winding diameter of No. 5 and an error signal between the tension detection voltage detected according to the tape tension supplied from the potentiometer 24 and the target tension voltage are added, and the control signal is added to the supply reel motor via the driver 18. The tape pack tension is controlled at a constant level. These winding retention values and pack tension values are determined by the command Ct supplied from the system controller 27.
This is done by The detailed operation of the reel control circuit 23 will be described later using FIG. 2.

Next, the operation during playback will be explained. The playback signal detected by the magnetic heads 3a and 3b during playback is sent to the amplifier &
The signals are sufficiently amplified by the switch 29, switched sequentially, and supplied to the video/audio processing circuit 30. Video and audio processing circuit 3
0, the reproduced signal is subjected to processing reverse to that during recording, converted into the original signal, and then outputted via the input/output terminals 31 and 32. Control of the drum 1 during reproduction is similar to that during recording described above. However, the reference signal RE, which serves as a reference for the drum rotation phase, is supplied from the video and audio processing circuit 30.
F is a signal that is synchronized with the synchronization signal of the input video signal during recording, but during playback, it is synchronized with a stable reference signal generated by a crystal oscillator etc. provided in the video and audio processing circuit 30. has been done.

Tape running control systems during playback can be roughly divided into two types. They are a capstan drive system and a reel drive system. The capstan drive method is similar to the tape running control and tension control during recording described above, except for capstan phase control. Capstan phase control during playback is to perform tracking control, and the playback CTL signal detected by the CTL head 12 and the reference signal REF supplied from the video/audio processing circuit 30 have a predetermined phase relationship. The phase error signal is fed back to the capstan motor 9 as shown in FIG. On the other hand, in the reel drive type tape running control, the pinch roller 11 is separated from the capstan 8 and the tape is run directly between the supply reel 15 and the take-up reel I9.

In this reel drive type tape speed control, the reel control circuit 23 calculates the tape speed from the take-up reel diameter and the take-up reel rotation period, and the tape speed is determined according to the speed command Ct supplied from the system controller 27. The difference from the target speed is fed back to the take-up reel motor 20 via the take-up reel driver 22. Note that the tape tension control on the supply v-reel side in this reel drive is the same as that in the recording described above, so a description thereof will be omitted here. In the capstan drive and reel drive, the pinch roller 11 is attached or detached by a control signal Cp supplied from the system controller 27.

Now, a specific example of the configuration and detailed operation of the reel control circuit 23 will be explained using FIG. 2. The second figure is a block diagram showing the configuration of the reel control circuit 23, and the part surrounded by the - dotted chain line is the reel control circuit. In FIG. 2, 34 is a reel winding diameter calculation circuit, 35 is a tension setting circuit, 36.37 is a supply and take-up reel tension generation circuit, 38 is a speed control circuit, 39 is a feedback tension control circuit 40, 41 is an addition circuit, and 42~
50 is an input/output terminal of the reel control circuit 230. Note that blocks with the same reference numerals as those in FIG. 1 are the same blocks as explained in FIG. 1. The winding diameters of both reels, which are the most basic in reel control, are calculated by the reel winding diameter calculation circuit 34 using the capstan FG and the FG of both reels. This reel winding diameter calculation differs depending on whether the capstan is driven or the reel is driven. When the capstan is driven, the tape running speed υ by the capstan and the tape winding speed and supply speed by both reels are equal, so the following formula (1) is obtained.
More sought after.

Here, υ: tape speed rc: capstan radius r (+ r z : radius of take-up reel and supply reel Tc, T,, T,: capstan 9 take-up reel.

The rotation period of the supply reel When one reel is driven, it can be determined from the rotation period of both reels and the tape winding area S of both reels using the following equation (2).

S−πSt+7E r2. D. Winding diameter data rL of both reels calculated as described above.

r is supplied to a speed control circuit 38 and tension generation circuits 36 and 37 for both reels. The tension generation circuits 36 and 37 for the supply reel and take-up reel receive setting tension information F, . . . supplied from the tension setting circuit 35.
According to FL, a control signal for generating a predetermined tape tension on both reels is supplied to each adder circuit 41 and 42. The tensicon generation control signal causes both reel motors to generate torque τ according to the following equation (3).

rt=rt・Ft, i−,=rs・Fs=・
(3) Here τ1. τS = Drive torque of take-up reel and supply reel r, , r: Radius of take-up reel and supply reel F, , F,
: Set tension value feedback of the take-up reel section and the supply reel section The tension control circuit 39 calculates the difference between the tension detection voltage supplied from the tension sensor and the target tension voltage determined according to the command supplied from the tension setting circuit 35. It is supplied to the adder circuit 41.

The adding circuit 41 adds the output of the feedback tension control circuit 39 and the output of the supply reel tension generation circuit 36 and outputs the result to the supply reel motor 6 via the supply reel driver 8. The speed control circuit 38 controls the tape speed when the reel is driven, and does not generate any signal when the capstan is driven. When driving the reel, the tape speed is calculated using the take-up reel's FG multiplied signal TFG signal) and the take-up reel radius r supplied from the reel winding diameter calculation circuit 34, and the tape speed is calculated using the take-up reel radius r supplied from the reel winding diameter calculation circuit 34, and the tape speed is calculated using the take-up reel radius r supplied from the reel winding diameter calculation circuit 34. The difference between the target tape speed and the target tape speed determined according to the above is supplied to the adder circuit 40 as a speed error signal. The adder circuit 40 adds the speed error signal and the take-up reel tension generation signal and supplies the result to the take-up reel motor 20 via the take-up reel driver 22. With the above configuration, in tape running control when the reel is driven, the take-up reel winds the tape at a constant tape speed, and the supply reel supplies the tape so that the tape tension is constant. Tape running control is performed.

The standby mode, which is the central feature of the present invention, will be explained below. As mentioned above, in the standby mode, in order to start recording quickly and in a timely manner, the drum is kept rotating in the state described above while the tape is stopped.

FIG. 3 is a diagram showing the relationship between the duration of this standby state and the degree of tape damage using tape tension as a parameter. Note that FIG. 3 shows an example of the characteristics of this apparatus, and the characteristics change depending on the materials, shapes, and environment of the tape and head. As can be seen from FIG. 3, in order to prevent damage to the tape in the standby state, the tape tension must be 10 gf or less and the duration must be 2.5 hours or less. Therefore, the first
In the embodiment shown in the figure, in the standby mode, the system controller 27 first supplies a command to each control system to realize the standby state. Therefore, in the standby mode, the drum control system rotates the drum 1 in synchronization with the synchronization signal of the input video signal as in recording, and the capstan control system stops the capstan 8. The reel control system then controls both reel motors 16 and 20 so that the tape tension is at a predetermined low tension, for example 10gf. Also,
In this embodiment, the pinch roller 11 in the standby state
is crimped to the capstan 8. In the above standby state, the standby state can be continued for up to 2.5 hours without damaging the tape.

However, in actual systems, when controlling tension with the tape stopped, the influence of friction in the tape running system becomes large, so there is a difference between the set tension and the actual tape tension at the drum contact area. occurs. Also,
Even if the tape tension at the drum abutting portion was accurately controlled to 10 gf, the upper limit of the standby state would be 2.5 hours or less. Therefore, in this embodiment, the tape is caused to run forward or backward by a predetermined amount not only when the tape tension decreases but also when the standby state continues for a certain period of time or more. This measures the duration of the standby state using the timer circuit 28 shown in FIG. 1, and supplies the duration information to the system controller 27. Then, the system controller 27 outputs a tape running command to the capstan control circuit 13 every time the duration of the standby state reaches a predetermined time, for example, one hour. In this case, in order to manage the running distance of the tape, in this embodiment, the system controller 27 counts the capstan FG signal or CTL signal. For example, in this embodiment, the tape is run for a number of frames every time the standby state continues for one hour, so the number n shown in the equation (4) below is calculated.
. The tape is run until the capstan FC is counted.

Here, k: Number of running frames such that the head scanning trajectories do not overlap ■ = Amount of tape running per second during recording ro: Radius of the capstan NcFc: Number of FG pulses per one rotation of the capstan The CTL signal is recorded. If a tape is attached, the amount of tape travel can be managed by counting CTL pulses instead of using the capstan FC. At this time, the number n of CTL pulses counted when running the tape for k frames. T1. is expressed by the following formula (5).

n (4L - to -n CTL ''' (5) Where, k: Number of running frames such that head scanning trajectories do not overlap NCTL: Capstan FG or CTL signal that is greater than or equal to the number of CTL pulses per frame is transmitted to the system controller 27 The amount of tape running can be managed in the standby state by counting at , and outputting a command Cc to the capstan control circuit 13 to stop tape running at a predetermined count value.

As explained above, according to this embodiment, the tape tension in the standby state is significantly lowered than the tension value during normal recording and playback, and the tape tension is lowered each time the duration of the standby state reaches a predetermined time. Since the tape can be run in the forward or reverse direction in small predetermined amounts, it is possible to achieve a long standby state without causing any damage to the tape, and it is possible to always start recording quickly and in a timely manner. This is effective in improving operability.

Next, another embodiment will be described using FIG. 4.

FIG. 4 shows a V with a standby function to which the present invention is applied.
It is a block diagram of TR. In FIG. 4, blocks given the same reference numerals as those in FIG. 1 perform the same operations as the blocks described in FIG. The VTR shown in FIG. 4 differs from the VTR shown in FIG. 1 in that the tape running control is different when the tape is run by a predetermined amount when the standby state continues for a predetermined time or more. Therefore, the operation of each block during recording and playback is as shown in Figure 1.
Since it is the same as that, the explanation will be omitted here. Hereinafter, the running of a small amount of tape in the standby state in the VTR shown in FIG. 4 will be explained.

The VTR shown in FIG. 4 is a system in which the pinch roller 11 is separated from the capstan 8 in the standby state. Therefore, in this case, if the standby state continues for a predetermined time or more, it is necessary to run the tape by driving the reel. Therefore, in this embodiment, the reel control circuit 2
The take-up reel radius r calculated in step 3 and the take-up reel FG multiplied signal (TFG signal) are supplied to the system controller 27. As a result, when the duration of the standby state reaches a predetermined time, in order to run the tape for k frames, the tape is reeled until the number of TFG pulses is counted by the number n TFG shown in equation (6) below. I try to run at

22, k: number of running frames such that head running trajectories do not overlap l: tape running amount per second during recording r: take-up reel radius N7. By calculating the winding diameter of the reel and the FC number of the reel so that the number of FG pulses per take-up reel is greater than the number of FG pulses per pass of the take-up reel, the amount of tape travel can be managed even when driving the reel.
In this embodiment as well, as in the embodiment shown in FIG. 1, a long standby state can be realized without damaging the tape.

Still another embodiment will be described with reference to FIG.

FIG. 5 shows a V with a standby function to which the present invention is applied.
It is a block diagram of TR. In FIG. 5, the blocks with the same reference numerals as the first prisoner perform the same operations as the blocks with the same reference numerals in FIG.

The biggest difference between the VTR of Section 5 and the VTR shown in FIGS. 1 and 4 is that an envelope detection circuit 51 and an AD converter 52 are newly provided.

This envelope detection circuit 51 and AD converter 5
2 is used for tape tension control in standby state. Hereinafter, referring to FIG. 5, the operation in the standby state when a recorded tape is loaded will be explained. Note that the standby state using a recorded tape referred to here refers to cases in which continuous recording is performed on a tape that has been partially recorded, or when formatting (when black burst signals, etc. are recorded). ). In this case, the fifth
The amplifier and switch circuit 29 is set to the playback mode and supplies the playback signals detected from the heads 3a and 3b to the envelope detection circuit 51. The envelope detection circuit 51 converts the envelope detection signal of the reproduced signal into an AD
It is supplied to the system controller 27 as a digital signal via the converter 52. At the start of the standby state, the system controller 27 outputs a tension command signal Ct to the reel control circuit 23 so that the tape tension becomes the tension value during recording or normal playback.

Then, the level of the reproduction envelope signal supplied from the AD converter 52 is detected, and it is determined whether the currently loaded tape is recorded or unrecorded.

If it is determined that the tape is unrecorded, the first
The operation of lowering the tape tension and feeding the tape by a small amount in accordance with the duration time in the standby state described in FIG. 4 or FIG. 4 is performed. On the other hand, if the tape is determined to be a recorded tape, the system controller 27 first stores the level of the reproduction envelope signal. And the reel control circuit 2
3. A tension control command Ct is output to gradually lower the tape tension. As the tape tension decreases, the contact between the magnetic heads 3a, 3b and the magnetic tape 33 gradually becomes lighter, and the reproduced signal level decreases. This decrease in the playback signal level is detected by a change in the level of the playback envelope signal supplied from the AD converter 52. Then, the level of the reproduction envelope signal is a certain ratio compared to the level at the normal tension,
For example, when the tension control command Ct becomes 1/2, the tension control command Ct is fixed and control is performed to maintain the tape tension at that time. The above-mentioned level 172 in this embodiment refers to the case where the maximum level point of the reproduced envelope signal is at level 172. As a result, compared to the feedforward type tension setting and tension control using a tension sensor, which were explained in the embodiment shown in FIG. High-precision tension control can be achieved without being affected.

In this embodiment as well, since the heads 3a and 3b scan the tape 33, the tape may be damaged if left on standby for a long time.

Therefore, as in the previous embodiment, the duration of the standby state is measured by the timer 28, and the tape is run a small amount at predetermined intervals.

As explained above, according to this embodiment, when a recorded tape is loaded, the tape tension is controlled by detecting the level of the playback signal, so that the tape tension of the part actually scanned by the head is set to a predetermined value. Since the value can be controlled to the value of , it is possible to further increase the reliability of preventing tape damage in the standby state.

Next, an embodiment will be described in which the present invention is applied to a digital magnetic recording and reproducing apparatus that converts a video signal into a digital signal instead of an analog signal and records and reproduces the same. An example of this digital magnetic recording/reproducing device is rD-
2NTSC Composite Digital VTRJ Television Society Technical Report.

11, 24. There is a device based on the recording format shown in pp. 13-18 (1987). As shown in Figure 6, the recording formats of this digital magnetic recording and reproducing device (hereinafter abbreviated as DVTR) are helical track (video data and 4 channels of digital audio data are recorded),
It consists of a linear track of channels. Digital data for one field is divided into six helical tracks and recorded. An example of a drum and head configuration that realizes such a recording format is the configuration shown in FIG.

The recording heads are RECI~4, and two heads are used at the same time to record two channels (two tracks) at a time, and one field is recorded in 1.5 revolutions of the cylinder.

Furthermore, a reproduction-only head PBI-4 is used. By separating the recording head and the reproducing head, (1) the signals recorded by the recording head can be read by the reproducing head, and the recorded signals can be simultaneously monitored, improving the reliability of recording.

(2) The reliability of recording and reproduction is improved because the characteristics of the recording head and the reproduction head can be respectively set optimally.

As described above, in a VTR, the playback head of PBI to PB4 is installed on a piezoelectric element such as a bimorph, and by changing the height of the head, tracking control during playback and moving control for noiseless playback at variable speed are performed. Some have built-in systems.

In the standby state of the DVTR with the head configuration shown in FIG.
RECI, PBI, RFe5. PF3 or RFe5. PF3. RFe5, PF4) will be scanned, and the effect of damage to the tape will be greater. Therefore, in the present invention, the moving head control system shown in FIG. 8 is used to prevent tape damage. FIG. 8 depicts the drum and head configuration and moving head control system. In FIG. 8, the playback head PB
I, PB2 and PF3. PF4 is a piezoelectric element 54, respectively.
The height is controlled by the control voltage channel supplied from the moving head control circuit 53. In this embodiment, in order to prevent the recording head and the reproducing head from scanning the same track on the tape in the standby state, the moving head control circuit 53 controls the reproducing head in comparison with the recording head in accordance with the command Cm from the system controller 27. The height of the reproducing head is controlled by the control voltage channel so that it is ahead or trailing by three tracks (corresponding to 1/2 field). FIG. 9 shows the scanning trajectories of the recording head and reproducing head in this standby state. The ninth factor is a diagram in which the height of the reproducing head is set to be three tracks behind the recording head. Tracks indicated by dotted lines in the figure represent tracks recorded by normal recording. Even in a VTR with a built-in moving head control system as described above, the tape can be run by a predetermined amount according to the duration of the standby state as explained in FIG. 1, Section 4, and FIG. conversion is done in the same way.

In this case, if the predetermined amount of tape travel is made equivalent to one field (6 tracks), the scanning trajectories of the recording head and the reproducing head will always have an interval of one track even after one field has been traveled. Even if the recording and reproducing heads are wide heads relative to the track width, overlapping scanning will not occur. Therefore, local damage to the tape can be prevented. Although the above description of FIG. 9 describes the case where the reproducing head follows the recording head, the same effect can be obtained even if the reproducing head is set to lead. Furthermore, the playback heads PB3 . A similar effect can be obtained even if PB4 is set to follow (lead).

As explained above, according to this embodiment, in a VTR equipped with a moving head control system, by changing the heights of the recording head and reproducing head during standby mode, concentration of the head scanning part can be avoided and tape damage can be avoided. This can be prevented.

In the above embodiment, there is a problem that the recording start point on the tape shifts due to frame advance when the standby state continues for a long time, but this can be solved by variable control of the rise characteristics of the tape running control system. This can be easily solved by

〔Effect of the invention〕

As explained above, according to the present invention, in the standby state, the tape tension value is lowered compared to that during recording or playback, and the tape is made to run a predetermined distance each time the duration of the standby state reaches a predetermined time. Therefore, a long standby state can be realized without causing any damage to the tape, and recording can be started quickly and in a timely manner. This allows the operability of the device to be significantly improved.

Furthermore, in the standby state when a recorded tape is loaded, the tape tension is controlled so that the playback signal level during the standby state is reduced by a predetermined ratio compared to the normal playback signal level.
Variations in tape tension due to friction in the tape running system, variations in reel motor characteristics, etc. can be suppressed, and the tape tension in the area actually scanned by the head can be accurately controlled.

This makes it possible to further improve the reliability of preventing damage to the tape in the standby state.

The above explanation is about the standby function at the start of recording, but if the control of the drum l in the standby state is switched to the drum control during playback explained in FIG. 1, playback can be started quickly and within the time υ-. It is clear that it is possible to realize a playback standby state that takes place immediately.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a VTR to which the present invention is applied, the second section is a block diagram showing a specific example of the configuration of a reel control circuit, and the third section is a characteristic diagram showing an example of the elapsed time in the standby state and the degree of tape damage. , FIGS. 4 and 5 are block diagrams of a VTR for explaining other embodiments, Section 6 shows a recording tape pattern of a digital magnetic recording and reproducing device, FIG. 7 shows a drum and head configuration section, and FIG. 8 9 is a block diagram of a DVTR showing another embodiment, and FIG. 9 is a diagram showing a head scanning locus in a standby state. 6...Drum control circuit 13...Capstan control circuit 23...Reel control circuit 27...System controller 28...Timer circuit 51...Envelope detection circuit 53...Moving head control circuit Punishment Candle 2 Diagram Q Hisamu 2 Le Standing ff15i Diagram Tori Interrogation Do O

Claims (1)

[Scope of Claims] 1. A helical scanning magnetic recording and reproducing device having a standby function of rotating a drum equipped with a magnetic head at a predetermined rotational speed in synchronization with a reference signal while the magnetic tape is stopped, comprising: The apparatus includes a running control means, a tape tension control means, and a timer means for measuring the duration of the standby state, and in the standby state, the tape tension value is lowered compared to that during recording or playback, and the duration of the standby state is reduced. A helical scanning magnetic recording/reproducing device characterized by a configuration in which the tape is moved forward or backward by a predetermined amount each time a predetermined time is reached. 2. A helical scanning magnetic recording and reproducing device having a standby function of rotating a drum equipped with a magnetic head at a predetermined rotational speed in synchronization with a reference signal while the magnetic tape is stopped, comprising: a tape running control means; The apparatus includes a tension control means, a timer means for measuring the duration of the standby state, and a reproduction signal level detection means, and in the standby state, the reproduction signal level is reduced by a predetermined ratio compared to the normal reproduction signal level. A helical scanning type magnetic recording/reproducing device characterized by a configuration in which the tape tension value is lowered and the tape is moved forward or backward by a predetermined distance each time the duration of the standby state reaches a predetermined time. 3. The tape running control means runs the tape by the rotation of the capstan, and the capstan F is generated at a frequency proportional to the rotation of the capstan.
The helical scan according to claim 1 or 2, wherein the tape running speed is controlled using G pulses, and the tape running a predetermined amount in a standby state is performed by counting the capstan FG pulses. A type of magnetic recording and reproducing device. 4. The tape running control means runs the tape by the rotation of the capstan, and generates a capstan F at a frequency proportional to the rotation of the capstan.
This mechanism uses G pulses to control the running speed of the tape, and during playback, controls the rotational phase of the capstan using control signal pulses recorded on the longitudinal track of the tape. 3. The helical scanning type magnetic recording and reproducing apparatus according to claim 1, wherein the traveling is performed by counting the control signal pulses. 5. The tape running control means runs the tape by the rotation of the reel, detects the running speed of the tape using the reel FG pulse generated at a frequency proportional to the rotation of the reel, and the tape winding diameter of the reel, and controls the tape. The helical according to claim 1 or 2, wherein the tape is configured to control the running speed, and is configured to run the tape by a predetermined amount in a standby state based on the product of the tape winding diameter of the reel and the count value of the reel FG pulse. A scanning magnetic recording/reproducing device. 6. A first group of heads mounted on the rotating drum facing each other at an angle of 180 degrees, and a group of heads mounted facing each other at an angle of 180 degrees at a location separated by a predetermined angle from the first head group. A moving head control function that variably controls at least one of the head groups in a direction orthogonal to the rotational direction of the drum, and a moving head control function that variably controls at least one head group in a direction perpendicular to the rotational direction of the drum, and a moving head control function that variably controls at least one head group in a direction perpendicular to the rotational direction of the drum, and a moving head control function that variably controls at least one of the head groups in a direction perpendicular to the rotational direction of the drum, and a moving head control function that variably controls at least one of the head groups in a direction perpendicular to the rotational direction of the drum, and a moving head control function that variably controls at least one of the head groups in a direction perpendicular to the rotational direction of the drum. A helical scanning magnetic recording and reproducing device having a standby function of rotating at a high speed, comprising a tape running control means, a tape tension control means, and a timer means for measuring the duration of a standby state, and in a standby state, the tape The tension value is lowered compared to that during recording or reproduction, and the head setting position of the second head group is set to scan a point separated by a predetermined distance from the scanning trajectory of the first head group on the tape. What is claimed is: 1. A helical scanning type magnetic recording/reproducing device characterized by a configuration in which the tape is variably controlled and the tape is moved forward or backward by a predetermined amount each time the duration of the standby state reaches a predetermined time.