JPH06309740A - Magnetic recording / reproducing device - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a magnetic recording / reproducing apparatus capable of obtaining a good head touch even when the number of rotations of a drum is particularly increased. [Structure] A plurality of recording modes having different drum rotation speeds are provided, and at the time of reproduction, reproduction is performed by changing the drum rotation speed according to the mode. Means 18 to 21 for discriminating the mode of the reproduction signal and means 22 to 26 for controlling the tape tension are provided, and the tape tension is changed according to the mode at the time of recording or reproducing. When the rotation speed of the drum is high, the tape tension is increased as compared with the low speed rotation, so that the increase in the air film can be prevented and the output can be prevented from being lowered even at the high speed rotation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording / reproducing apparatus for recording / reproducing by winding a magnetic tape around a rotary drum, and more particularly to an apparatus capable of recording / reproducing a plurality of kinds of signals having different recording rates.

[0002]

2. Description of the Related Art In recent years, high definition (hereinafter referred to as HD)
Although VTRs for recording signals are being developed, both types are mixed in the transition period from current broadcasting (hereinafter referred to as NTSC) to HD broadcasting, and it is desired that both types of VTRs can be recorded on the same deck.

There is a difference of about 5 times in the information amount between NTSC and HD, and naturally the recording rate also changes.
In this way, two types of signals with different recording rates are sent to the same VT.
Considering recording with R, the following two methods can be considered. The first method is to change the number of recording heads and tape speed while keeping the drum rotation speed constant, and the second method is to change drum rotation speed and tape speed without changing head number. is there.

Comparing the two, the cost of the head,
From the viewpoint of tape vibration due to hitting of the head or miniaturization of the drum due to miniaturization of the device, it is preferable that the number of heads is as small as possible, and the number of heads is increased without increasing the number of heads to record the higher rate signal. The method to do is a good idea.

[0005]

In the case of such a VTR, for example, the number of rotations of the drum during recording / reproducing in the high rate mode may be at least twice as high as that during recording / reproducing in the low rate mode. , In that case, the air film between the tape and the drum increases. As a result, there is a problem in that the spacing between the tape and the head is increased and the output is reduced due to a head touch failure.

Therefore, an object of the present invention is to provide a magnetic recording / reproducing apparatus capable of obtaining a good head touch even when the number of rotations of the drum is particularly increased.

[0007]

In order to achieve the above object, the magnetic recording / reproducing apparatus of the present invention has a plurality of recording modes in which the number of rotations of the drum is different, and at the time of reproduction, the number of rotations of the drum depends on the mode. Although it is designed to change the reproduction speed, it is provided with a means for discriminating the mode of the reproduction signal and a means for controlling the tape tension, and the tape tension is changed according to the mode during recording or reproduction. Is.

[0008]

According to the present invention configured as described above, when the rotation speed of the drum is high, the tape tension is increased as compared with the low speed rotation, so that the increase of the air film is prevented and the output is achieved even at the high speed rotation. There can be no drop.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a magnetic recording / reproducing apparatus according to the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a tape path of a VTR in this embodiment, FIG. 2 is a diagram showing an example of a head configuration of a rotary drum, and FIG. 3 is a recording pattern diagram on a tape.

In FIG. 1, reference numeral 1 is a cassette, and a tape 4 is wound between a supply side reel 2 and a winding side reel 3 of the cassette. Reference numerals 5 and 6 are a supply-side reel stand and a take-up reel stand, respectively. When the cassette 1 is loaded in the apparatus, both reels 2 and 3 in the cassette 1 are engaged with each other. The reel bases 5 and 6 are driven by a supply-side reel motor and a winding-side reel motor (not shown).

Reference numeral 7 is a rotary drum on which a magnetic head is mounted, and is mounted at a predetermined angle with respect to the substrate. As shown in FIG. 2, two magnetic heads A1, A2, B1 and B2 are arranged on the rotary drum 7 so as to face each other. In addition, in FIG. 2, + and-signs represent the direction of azimuth. Reference numeral 8 is an inclined post that regulates the tape entry direction with respect to the entrance side of the rotary drum 7, and 9 is a vertical guide post that regulates the tape height on the drum entrance side. Reference numeral 10 designates a slanting post for defining the detaching direction of the tape 4 from the drum outlet side and returning the tape 4 to be parallel to the reference plane, and 11 a vertical guide post for regulating the height of the tape 4 on the drum outlet side. Is.

Reference numeral 12 is a tension post, which is erected on a tension arm (not shown), in which a magnet attached to a part of the tension arm and a Hall element fixed on the substrate face each other. The tension is detected by the output from the Hall element, the voltage of the reel motors on both the supply side and the winding side is controlled, and the tape tension is controlled.

Reference numeral 13 denotes a pinch roller, which is pressed against the capstan 14 while the tape is running, and the tape 4 is conveyed by the rotation of the capstan 14. In addition, a tape path is formed by the vertical posts 15 and 16.

Of the guide posts, vertical posts 9 and 11,
15 and 16, tension post 12, inclined post 8,
The pinch roller 13 and the pinch roller 13 are located in the cassette opening 1a when the cassette is loaded, and the tape 4 in the cassette 1 is pulled out by the loading operation and wound around the drum 7.

Next, the recording pattern will be described with reference to FIG. At the time of recording, two adjacent heads simultaneously write signals, and a pair of heads facing each other alternately write signals, resulting in a pattern as shown in FIG. The heads are arranged so that adjacent tracks do not have the same azimuth angle.

In the case of high-rate recording, the number of rotations of the rotary drum is N times and the tape speed is also N times, so the number of tracks per frame is N times, but as a recording pattern. Will be the same. At the beginning of writing each track, a mode determination signal 17 for determining whether the track is high-rate recording or low-rate recording
Is recorded.

Next, the drum and capstan motor control and tension control during recording and reproduction will be described. Figure 4
FIG. 5 is a schematic block diagram of a circuit relating to control of each motor during recording / reproduction, and FIG. 5 is a flowchart showing a flow of tension control during reproduction.

At the time of reproduction, the signal read by the head 18 is sent to the signal processing circuit 20 through the reproduction amplifier 19 and at the same time to the mode signal separation circuit 21.
Then, the mode signal separation circuit 21 sends the mode signal information to the CPU 22. The CPU 22 determines whether the reproduced signal is in the high rate mode or the low rate mode from the mode signal, and instructs the tape tension control according to the mode. The tape tension control control according to the mode will be described below with reference to the flowchart of FIG.

In step S1, a reproduction mode signal indicating the high rate mode or the low rate mode is detected from the information of the mode signal input from the mode signal separation circuit 21. Then, in step S2, it is determined whether the signal being reproduced at that time is in the high rate mode or the low rate mode. If the signal is in the low rate mode, the process proceeds to step S3, and the high rate mode is resumed. If it is, the process proceeds to step S4.

In step S3, a speed command is sent to the drum servo circuit 24 and the capstan servo circuit 23 in order to rotate the rotary drum 7 and the capstan 14 at predetermined rotational speeds corresponding to the low rate mode. . In response to this command, the drum servo circuit 24 and the capstan servo circuit 23 control the motors 26 and 25 that drive the rotary drum 7 and the capstan 14, respectively, and rotate them at a predetermined rotation speed.

In step S4, a speed command is issued to the drum servo circuit 24 and the capstan servo circuit 23 in order to rotate the rotary drum 7 and the capstan 14 at predetermined rotational speeds higher than those in the low rate mode. Send out. In response to this command, the rotary drum 7 and the capstan 14 rotate. At this time, a command is given to the reel servo circuit 29 so that a predetermined tension higher than that in the low rate mode is applied to the tape 4 as well. Is sent. In addition, the tape tension is the Hall element 2
The output of 7 is passed through the Hall element output detection circuit 28 to the CPU
It is taken in by the CPU 22 and is controlled by the reel servo circuit 29 to control the voltage of the supply side and take-up side reel motors 30 and 31, so that the tension is maintained at a predetermined tension based on a command from the CPU 22. In this way, by giving the tape 4 a predetermined tension higher than that in the low rate mode, the air film itself can be made substantially the same as that in the low rate mode, and the output reduction due to the head touch failure is prevented. , It is possible to obtain a sufficient output.

After the operation in step S3 or step S4 as described above, in step S5,
Whether or not the stop button has been pressed is detected, and until it is pressed, the process returns to step S1 and the subsequent operations are repeated.
When the capstan 14 is pressed, the process moves to step S6 and the capstan 14 is stopped.

At the time of recording, the high-rate mode or the low-rate mode is determined by the mode switching button of the operation unit 32, and the rotational speeds of the rotary drum 7 and the capstan 14 and the tape tension are controlled according to the mode. To be done. In addition to the case of using the mode switching button, a configuration may be adopted in which automatic switching is performed according to an input signal.

As described above, according to the present embodiment, the tape tension is increased in the mode in which the rotary drum 7 rotates at a high speed as compared with that in the mode in which the rotary drum 7 rotates at a low speed, thereby suppressing the increase of the air film due to the high speed rotation of the rotary drum 7. Therefore, good head touch can be obtained regardless of the mode.

In the first embodiment described above, the device using the electric tension control system has been described.
A mechanical control method using a band brake or the like can also be realized by switching the tension with the tension switching mechanism.

By the way, as described above, in the VTR of this type which is compatible with both the HD and NTSC systems, the recording in the low rate mode and the recording in the high rate mode may be mixed on one tape. When reproducing such a tape, when the mode changes during the reproduction, the drum rotation speed must be changed according to the mode. Then, in order to minimize image drooling at the transition, it is necessary to stabilize the changed rotation speed in a short time. Therefore, a magnetic recording / reproducing apparatus according to the second embodiment of the present invention which can quickly stabilize the target rotation speed when the drum rotation speed changes will be described.

In the second embodiment, the operation when the recorded mode changes during reproduction will be described. FIG. 6 is a flowchart showing the flow at the time of mode transition.
The circuit configuration relating to the reproduction mode transition is basically the same as that shown in FIG. 4 described in the first embodiment.
In the present embodiment, the processing of the CPU 22 is added to the first embodiment.

Referring to FIG. 6, during reproduction, the reproduction mode signal is always detected in step S11, and the mode discrimination signal reproduced from the tape 4 is compared with the mode discrimination signal of the previous track. In S12, it is determined whether the mode has changed. Then, when the mode is changed during reproduction, the signal is detected in step S14, and it is determined whether or not the mode is the high rate mode. If there is no mode change, the process returns to step S11, but if the stop button is pressed midway (step S13)
Moves to step S20.

When the mode is changed to the high rate mode, in step S15, the tape tension is temporarily weakened as will be described later, and in step S16, the rotational speed of the rotary drum 7 and the capstan 14 is increased. On the other hand, when the mode is changed to the low rate mode, in step S17, the tape tension is temporarily strengthened as will be described later, and in step S18, the rotational speeds of the rotary drum 7 and the capstan 14 are decreased, and thus, the predetermined speeds are set. The servo target values of the drum motor 26 and the capstan motor 25 are switched so that the rotation speed is reached. Then, in step S19, until the stop button is pressed,
Returning to step S11 and thereafter, when the mode change is detected and the stop button is pressed, the process proceeds to step S20, and the capstan 14 is stopped.

Here, FIG. 7 shows the relationship between the change of the drum rotation speed and the change timing of the tape tension for the tape tension at the time of this switching. For example, when the low rate mode is changed to the high rate mode (see FIG. 7).
(A)), that is, when increasing the number of rotations of the drum,
Decrease the tape tension for a certain time. On the other hand, in the opposite case, as shown in FIG. 7B, the supply-side reel motor 30 is controlled so as to increase the tape tension, and after a certain period of time, a predetermined tension corresponding to the changed mode is set. To

Thus, according to the second embodiment of the present invention,
When the number of rotations of the rotating drum becomes high when the mode changes during playback, the resistance to the motor is reduced by temporarily loosening the tape tension, thereby reaching the target number of rotations and stabilizing at that number of rotations. The time to get to is much shorter. On the contrary, when the number of rotations is low, the tape tension is increased to increase the resistance to the motor, and in this case also, the number of rotations is quickly stabilized to that number. In this way, when the mode is changed, the time until the rotational speed stabilizes is shortened, and the image disturbance time at the mode change can be suppressed to the minimum.

In this embodiment, corresponding to the first embodiment, the tape tension after changing the number of rotations is set to be large when the number of rotations of the drum is high and small when the number of rotations is low. However, the present invention can also be applied to those in which the tape tension set by changing the rotation speed is not changed. Furthermore, when the mode applied in this embodiment changes, the method for determining the mode is
It can also be applied to the first embodiment described above and vice versa.

In this embodiment, the mode transition during reproduction is described, but the same operation is performed when the mode is changed during recording. Further, in the present embodiment, the device using the electric tension control system has been described, but a mechanical control system using a band brake or the like can also be realized by switching the tension with the tension switching mechanism. .

[0034]

As described above, according to the present invention, by increasing the tape tension in the mode in which the drum rotates at a high speed than in the mode in which the drum rotates at a low speed, it is possible to suppress the increase of the air film due to the high speed rotation of the drum. , Regardless of the mode, you can always get a good head touch.

[Brief description of drawings]

FIG. 1 is a diagram showing a VTR tape path in a magnetic recording / reproducing apparatus of the present invention.

FIG. 2 is a diagram showing a head configuration example of a rotary drum in the magnetic recording / reproducing apparatus of the present invention.

FIG. 3 is a recording pattern diagram on a tape in the magnetic recording / reproducing apparatus of the present invention.

FIG. 4 is a schematic block diagram of a circuit relating to each motor control during recording / reproduction according to the first embodiment of the magnetic recording / reproduction device of the present invention.

FIG. 5 is a flowchart showing the flow of tension control during reproduction according to the first embodiment of the magnetic recording / reproducing apparatus of the present invention.

FIG. 6 is a flowchart showing the flow of tension control at the time of mode transition according to the second embodiment of the magnetic recording / reproducing apparatus of the present invention.

FIG. 7 is a diagram showing timings of drum rotation speed change and tape tension change at the time of mode transition according to the second embodiment of the magnetic recording / reproducing apparatus of the present invention.

[Explanation of symbols]

 1 cassette 2 supply side reel 3 winding side reel 4 tape 5 supply side reel stand 6 winding side reel stand 7 rotating drum 8 tilting post 9 vertical guide post 10 tilting post 11 vertical guide post 12 tension post 13 pinch roller 14 capstan 15 vertical post 16 vertical post 17 mode discrimination signal 18 head 19 reproduction amplifier 20 signal processing circuit 21 mode signal separation circuit 22 CPU 23 capstan servo circuit 24 drum servo circuit 25 capstan motor 26 drum motor 27 hall element 28 hall element output detection Circuit 29 Reel servo circuit 30 Supply side reel motor 31 Winding side reel motor 32 Operation part

Claims (2)

[Claims] 1. A recording / reproducing apparatus having a plurality of recording modes with different drum rotation speeds, and reproducing the reproduction by changing the drum rotation speed according to the mode when the reproduction is performed. A magnetic recording / reproducing apparatus comprising: a means and a means for controlling the tape tension, and changing the tape tension according to a mode during recording or reproduction. 2. A recording / reproducing apparatus having a plurality of recording modes having different drum rotation speeds, and reproducing the reproduction by changing the drum rotation speed according to the mode at the time of reproduction. Equipped with means for discriminating and means for controlling tape tension, while changing the drum rotation speed when the mode changes during recording or reproduction,
A magnetic recording / reproducing apparatus characterized by temporarily changing the tape tension.