JPH09128849A - Magnetic recording/reproducing device and speed control method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic recording/reproducing device capable of keeping a relative speed between a magnetic head and a magnetic tape almost constant at a high speed search time and to provide the speed control method therefor. SOLUTION: When the rotational speed of a rotary drum rises and falls at the high speed search time, a torque controller 103 operates a drum motor drive part 116 so that torque of a drum motor coincides nearly with prescribed torque. Then, when the rising operation and the falling operation of the rotational speed of the rotary drum are ended, a drum speed controller 105 operates the drum motor drive part 116 so that the rotational speed of the rotary drum is almost matched with the prescribed rotational speed. Further, a tape speed command generation circuit 113 outputs a speed command value so that the magnetic tape runs at a nearly fixed relative speed for the magnetic head loaded on the rotary drum, and operates a reel system drive controller 14 according to the rotational speed of the rotary drum to run the magnetic tape.

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 such as a digital video cassette recorder (hereinafter referred to as VCR), and more particularly to a magnetic recording / reproducing apparatus capable of precisely controlling the speed of a magnetic tape and a rotating drum. And a speed control method thereof.

[0002]

2. Description of the Related Art Conventionally, a magnetic recording device capable of high-density recording of digital signals (for example, a rotary head type V
In CR), a rotary magnetic head arranged on the drum is used to record or reproduce digital signals such as audio and images on a magnetic tape wound around the drum at a predetermined winding angle. Hereinafter, a VCR will be described as an example of the magnetic recording / reproducing apparatus.

In this VCR, during normal reproduction, the running speed of the magnetic tape and the rotating speed of the drum are servo-controlled so that the relative speed in the track direction between the magnetic tape and the rotary magnetic head becomes constant. On the other hand, at the time of so-called search reproduction, in which the time recorded in the subcode, the absolute track address, etc. are detected while fast-forwarding or rewinding the magnetic tape, the magnetic tape is fed at a high speed, so the drum rotation speed during normal playback is Relative speed changes compared to normal playback.

The above will be described with reference to the drawings. FIG.
During normal reproduction (when the tape is transferred at the same tape speed as during recording to obtain a reproduced image) and during 10x speed reproduction (in the same direction as during recording, at 10 times the tape speed during recording in the FF direction (when a magnetic tape is FIG. 7 is a diagram schematically showing a head scanning locus when a tape is transferred in a feeding direction) to obtain a reproduced image. In FIG. 7, 701 is a magnetic tape, 702 is the tape transport direction, and strip-shaped 703 is a recording track group magnetized and recorded by a rotary magnetic head. 7
The locus from 04 to 705 is a head scanning locus during normal reproduction, and the locus from 704 to 706 is a head scanning locus during 10 × speed reproduction. The locus from 704 to 707 is a projection of the head scanning locus during 10 × speed reproduction in the direction of one recording track.

The length of the line segment connecting 704 and 705 is proportional to the relative speed between the magnetic head and the magnetic tape during normal reproduction, and the length of the line segment connecting 704 and 707 is at 10 × speed reproduction. Is proportional to the recording track direction component of the relative speed between the magnetic head and the magnetic tape. Therefore, if the drum rotation speed is constant, the relative speed of the component in the recording track direction is different between the normal reproduction and the 10 × speed reproduction, and the transmission rate of the signal reproduced from the recording track is different.

Since the signal processing system (not shown) generally used in the VCR is compatible with a constant transmission rate, the recording track direction component of the normal component during the normal reproduction and the high speed search as described above. When the relative speed changes in a wide speed range, the signal itself may not be read properly.
Therefore, when a high-speed search is performed in the FF direction as shown in FIG. 7, by rotating the drum rotation speed faster than the drum rotation speed during normal reproduction, the track direction component of the relative speed between the magnetic tape and the rotary head. Can be controlled to be substantially the same as the relative speed during normal reproduction (hereinafter, the relative speed is referred to as constant). When performing a high-speed search in the REW direction (direction in which the magnetic tape is rewound), the relative speed is kept constant by rotating the drum rotation speed slower than the drum rotation speed during normal reproduction, as opposed to the FF direction. It becomes possible to do.

Here, for example, when a high-speed search such as 200 times speed is considered, the tape speed is suddenly increased to 200 times, etc., in consideration of the followability of the drum rotation speed and damage to the head and the tape. It is not difficult to start at a high speed, and it is common to use soft start. As the search speed becomes higher, it is necessary to read the data correctly at all times, and it is necessary to perform speed control so that the relative speed becomes constant even during the transition of the rising and falling of the tape speed. Therefore,
Conventionally, the feeding speed of the magnetic tape is detected, and the rotation speed of the drum is controlled so that the relative speed becomes constant from the feeding speed of the magnetic tape.

FIG. 8 is a block diagram showing the structure of a speed control unit of a conventional magnetic recording / reproducing apparatus. In FIG. 8, the tape speed command generator 801 is linearly proportional to the time such that, in the case of performing a soft start of 200 times in 2 seconds, it becomes 200 times the normal feeding speed of the magnetic tape in 2 seconds. Output the speed command value. Reel system drive controller 114
Is fed back the output from the tape speed detecting device 115 for detecting the feeding speed of the magnetic tape, and drives the reel system so that there is no difference from the speed command value from the tape speed command generating device 801. With this configuration, the feeding speed of the magnetic tape is controlled.

On the other hand, the output signal from the magnetic tape speed detecting device 115 is input to the drum speed command generating device 802, and a command corresponding to the magnetic tape feeding speed is sent to the drum speed control device 803. Then, a signal from the drum speed control device 803 is input to the drum motor drive unit 116 to control the rotation speed of the drum. That is, the rotation speed of the drum is controlled by the closed loop so that the relative speed becomes constant according to the magnetic tape speed detected moment by moment. In the drum driving device 116, it is a voltage-current conversion unit of the 109 drum motor, and gm is its coefficient. Reference numeral 110 is a current-rotation speed conversion unit of the drum motor, Kt is its coefficient, and Jd is the moment of inertia of the drum motor. 111 is the number of rotations of the drum motor
It is a voltage converter, and Ke is its coefficient.

However, in this apparatus, since the rotational speed of the drum is controlled according to the feeding speed of the magnetic tape, the followability of the drum becomes a problem. That is, when the speed command is changed linearly with respect to time, the rotational speed of the drum rises with a slight delay, and the error from the target speed increases with time. FIG. 9 is a diagram showing a speed change of the rotating drum with respect to the speed command value at the time of rising. Here, the drum speed control system is a first-order lag system, the DC gain is about 30 dB, the control band is about 8 Hz, and the rising time to the target is set to 2 seconds. The rotation speed 902 of the drum rises slightly later than the speed command value 901, and the speed difference from the speed command value 901 increases with the passage of time, and the steady deviation remains even after the speed command value becomes constant. You can see that. Here, in order to improve the tracking characteristic of the drum, it is necessary to design a complicated control system such that integral compensation is inserted to earn DC gain and phase compensation is inserted to secure a necessary control band. There is a problem that it does not happen.

As a magnetic recording / reproducing apparatus for solving this problem, the rising speed of the magnetic tape and the rising rotation speed of the rotating drum are divided into a plurality of times from the start of the search until the target speed is reached, and the respective times are set. The correspondence with the desired speed at that time is stored in the memory, the time from the start of the search is monitored during high-speed search, the desired speed at that time is obtained from the memory, and a command is sent to the speed servo circuit to determine the tape speed. There is known a magnetic recording / reproducing apparatus which controls the drum rotation speed and the drum rotation speed stepwise (Japanese Patent Publication No. 5-84582).

[0012]

However, in the magnetic recording / reproducing apparatus disclosed in Japanese Patent Publication No. 5-84582, the higher the search double speed, the more the plural correspondences from the start of the search to the target speed are stored in the memory. However, there is a problem that the storage capacity increases.

In view of the above-mentioned problems, the present invention is capable of reading data correctly with a simple circuit configuration from the start to the end of high-speed search while keeping the relative speed between the magnetic tape and the magnetic head mounted on the rotating drum constant. An object of the present invention is to provide a magnetic recording / reproducing apparatus and a speed control method thereof.

[0014]

According to a first aspect of the present invention, there is provided a magnetic recording / reproducing apparatus in which a magnetic tape is fed to a rotary drum by a magnetic tape feeding section and is rotated by a drum motor to be mounted on the rotary drum. In the magnetic recording / reproducing apparatus for recording / reproducing a signal on / from the magnetic tape by moving the recorded magnetic head relative to the magnetic tape, and for searching the absolute address etc. recorded on the magnetic tape at a high speed, rotation of a rotating drum. A rotation speed detecting means for detecting the speed and a torque of the drum motor are substantially equal to a predetermined torque when the rotation speed of the rotating drum rises or falls during a high speed search.
Based on the detection results of the torque control means for rotating the drum motor and the rotation speed detection means, it is determined whether the rising operation and the falling operation of the rotation speed of the rotating drum at the time of high-speed search are completed, and the rotation speed of the rotating drum rises. After the end of the operation and after the end of the falling operation, the rotation speed control means for controlling and rotating the drum motor so that the rotation speed of the rotary drum becomes a substantially constant speed, and the detection result of the rotation speed detection means during the high speed search. Based on, the speed command value of the magnetic tape feed speed for keeping the relative speed between the magnetic head mounted on the rotating drum and the magnetic tape constant,
It is provided with a feeding speed commanding means for outputting to a magnetic tape feeding portion.

That is, the torque of the drum motor is controlled at the transition of the rising and falling of the drum rotation speed (hereinafter referred to as torque control), and the speed control is performed at a steady state in which the constant speed must be maintained. The rotation of the rotary drum is controlled by switching to, and the feeding speed of the magnetic tape is adjusted according to the rotation of the rotary drum. In the above configuration, the problem of the followability of the rotating drum having a large inertia is eliminated, and the followability to the speed command value only needs to be considered in the magnetic tape feeding system. It will be easy.

A magnetic recording / reproducing apparatus according to a second aspect of the present invention is the magnetic recording / reproducing apparatus according to the first aspect, wherein the speed command value output by the feed speed commanding means is a magnetic head mounted on a magnetic tape and a rotary drum. Is a value obtained by adding a feeding speed of the magnetic tape for keeping the relative speed to and constant and a value proportional to the differential value of the feeding speed of the magnetic tape.

According to this magnetic recording / reproducing apparatus, the follow-up of the magnetic tape feed speed to the speed command value is further improved,
It is possible to control the running of the magnetic tape with high precision according to the rotation of the rotating drum.

A magnetic recording / reproducing apparatus according to a third aspect of the present invention is the magnetic recording / reproducing apparatus according to the first or second aspect, in which the feed speed command means determines the magnetic tape from the rotational speed detected by the rotational speed control means. And a speed converting means for obtaining the feeding speed of the magnetic tape so that the relative speed between the magnetic head mounted on the rotating drum and the magnetic head becomes constant.

According to this structure, since the speed command value can be calculated from the output of the speed converting means, it is not necessary to store the feeding speed of the magnetic tape in the memory, and the conventional high speed can be achieved. It is not necessary to monitor the time from the start of the search, and the speed control mechanism can be simplified.

According to another aspect of the magnetic recording / reproducing apparatus of the present invention, the feed speed commanding means controls the rotation speed of the rotary drum during the high speed search from the rising to the ending of the rotation speed, and
A plurality of predetermined times from the fall to the end of the fall and the rotation speed of the rotating drum at that time are measured in advance, and a speed command value based on the known rotation speed of the rotating drum is stored in advance. And the speed command value stored in the storage means for each of the plurality of predetermined times from the start of the high-speed search are sequentially read,
And a memory reading unit for outputting to the tape feeding unit.

In this configuration, when the high speed search is started, the rotary drum is rotationally driven by torque control. On the other hand, the feeding speed of the magnetic tape is speed-controlled by a speed command value output from the storage means at the predetermined time, regardless of the rotation speed of the drum detected by the rotation speed control means. This also makes it possible to control the speed so that the relative speed between the magnetic head mounted on the rotary drum and the magnetic tape becomes substantially constant.

A speed control method according to a fifth aspect of the present invention is the magnetic recording / reproducing apparatus according to the fourth aspect, wherein the storage means comprises:
From the rotational speed of the rotating drum, which is known in advance by measurement, the magnetic tape feeding speed for keeping the relative speed between the magnetic tape and the magnetic head mounted on the rotating drum constant, and the feeding speed of the magnetic tape. It is characterized in that it is a value obtained by adding a value proportional to the differential value.

According to this structure, the magnetic tape of the magnetic recording / reproducing apparatus according to the fourth aspect can better follow the speed command value of the magnetic tape feed speed.

According to a sixth aspect of the present invention, in the speed control method, the magnetic tape is moved by the magnetic tape feeding unit and the rotary drum is rotated by the drum motor, so that the magnetic tape is mounted on the magnetic head mounted on the rotary drum. In the speed control method at the time of high-speed search of the magnetic recording / reproducing apparatus for recording / reproducing a signal on / from the magnetic tape by moving it relative to the magnetic tape, the drum motor is predetermined when the rotational speed of the rotating drum rises and falls. The drum motor is controlled to rotate so as to substantially match the torque, and the end of the rising and falling operations of the rotation speed of the rotating drum during high-speed search is determined, and the rotation speed of the rotating drum during high-speed search is determined. After the end of the rising operation and the end of the falling operation of the So that a constant speed, the speed control method characterized by rotating the drum motor.

According to this speed control method, the relative speed between the magnetic tape and the magnetic head mounted on the rotary drum can be kept substantially constant by using a device having a simple structure.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) FIG. 1 is a schematic block diagram showing the structure of a speed controller of a magnetic recording apparatus according to the first embodiment. The same parts as those in FIG. 6 are designated by the same reference numerals and the description thereof will be omitted.

In the magnetic recording / reproducing apparatus of the present embodiment, the torque at the time of rising (hereinafter referred to as start) or falling (hereinafter referred to as end) of the rotational speed of the rotating drum during high-speed search. The command generation circuit 102 outputs a predetermined torque value, and the torque control device (torque control means in the claims) 103 causes the torque detection circuit 112.
The drum motor drive unit 116 is operated so that the torque of the drum motor detected in step S3 reaches the predetermined torque value. As a result, the drum motor, and thus the rotary drum, rotates with a substantially constant torque.

On the other hand, a tape speed command generation circuit (feed speed command means and speed conversion means in the claims) 1
Reference numeral 13 denotes a reel drive device (a magnetic tape feeding portion in claims) based on the rotation speed of the rotating drum 114.
The speed command value is output to. Reel system drive controller 114
Causes the magnetic tape to travel so that the feeding speed of the magnetic tape detected by the tape speed detecting device 115 matches the speed command value. As a result, the relative speed between the magnetic tape and the magnetic head mounted on the rotating drum is kept substantially constant.

When the rotation speed of the rotating drum reaches a predetermined rotation speed (second rotation speed command value: ω _2ref ),
Based on an instruction from the control mode switching device 107, a signal input by the switch 108 to the drum motor drive unit 116 is
From the output of the torque control device 103 to the drum speed control device 1
Switch to output 05. Drum speed control device 105
Controls the drum motor drive unit 116 so that the rotating drum rotates at a target rotation speed (first rotation speed command value: ω _1ref ) at a constant speed (hereinafter, referred to as speed control). In this case as well, the feeding speed of the magnetic tape is controlled so as to be a speed corresponding to the rotation speed of the rotary drum.

In FIG. 1, 109 is a voltage-current converter of the drum motor, and gm is its coefficient.
Reference numeral 110 is a current-rotation speed conversion unit of the drum motor,
t is its coefficient, and Jd is the moment of inertia of the drum motor. Reference numeral 111 is a rotation speed-voltage conversion unit of the drum motor, and Ke is a coefficient thereof.

The above is the outline of the speed controller of the magnetic recording / reproducing apparatus of FIG.

Below, regarding the speed control method, FF
A detailed description will be given by taking as an example the start of a high-speed search in the direction.

First, the rotation control of the rotary drum will be described.

First, a signal indicating the search direction (FF direction) and a search start command are input from the input terminal 101, and the first rotation speed command value (target speed: ω _1ref ) is input from each of the input terminals 104 and 105. , The second rotation speed command value (mode switching speed: ω _2ref ) is input.
The second rotation speed command value ω _2ref is set to a value slightly lower than the first rotation speed command value ω _1ref .

Then, the torque command generating circuit 102 outputs to the torque control device 103 an acceleration torque command value (+ T _ref ) necessary for linearly raising the rotation speed of the drum with time. Further, since the rotation speed ωd of the rotary drum which is the output of the drum motor driving unit 16 is lower than the second rotation speed command value ω _2ref , the control mode switching device 1
07 switches the switch 108, and the torque control device 1
The output of 03 is input to the drum motor drive unit 116. As a result, the rotational speed of the drum is torque controlled.

Then, the torque control device 103 controls the drum motor drive unit 116 so that the measured torque value Td of the drum motor drive unit 116 detected by the torque detection circuit 112 matches the torque command value (± T _ref ). To do.

Subsequently, when the drum speed ω _d matches the second rotation speed command value ω _2ref , the control mode switching device 107 causes the drum speed ω _d and the second rotation speed command value ω 2 to change.
_Based on the result of comparison with _2ref , the switch 108 is switched and a signal to be input to the drum motor drive unit 116 is output from the output of the torque control device 103 to the drum speed control device 10.
Switch to 5 output. That is, the torque control is switched to the speed control. Thus, since the drum speed omega _d is up to a second rotational speed command value omega _2ref a constant acceleration drive with a constant torque, drum speed omega _d is beyond the second rotational speed command value omega _2ref speed The speed can be controlled so that the command value ω _1ref and the measured value ω _d of the speed of the drum motor always match. Thus, by switching the control mode at the second rotation speed command value ω _2ref which is set to a value slightly lower than the first rotation speed command value ω _1ref, it is possible to prevent overshoot of the drum rotation speed. it can.

If the DC gain of the drum control system is not sufficient, the speed deviation remains in the speed control of the speed control device 105. Therefore, the first drum speed command value ω _1ref is set to the final target value of the drum rotation speed or more. It is desirable to set it a little higher. This makes it possible to further reduce the speed deviation. FIG. 2 shows the first drum speed command value ω
It is a figure which shows the speed change of a rotating drum when _1ref is set to 3% higher than the final target value of a drum rotation speed. However, the drum control system has a DC gain of about 30 dB and a control band of about 8 Hz. The rotation speed of the drum follows the steady-state deviation almost 2 seconds after the start-up until 2 seconds.

With the above construction, the rotational speed of the rotary drum can be linearly and accurately controlled to the target speed.

Next, the control of the magnetic tape feeding speed will be described.

The tape speed command generating circuit 113 makes the relative speed of the magnetic tape feeding speed to the rotating speed of the rotating drum constant by a speed converting means (not shown) based on the drum rotating speed ω _d detected moment by moment. A target value of the magnetic tape feeding speed is calculated, and a speed command value of the magnetic tape is generated. The reel drive control device 114 for controlling the magnetic tape feed speed controls the magnetic tape so that the speed command value from the tape speed command generation circuit 113 and the magnetic tape feed speed detected by the tape speed detection device 115 match. Let it run.

As described above, in the present embodiment, the rotating drum is rotated by torque control, and the reel system for feeding the magnetic tape is driven in accordance with the rotation speed to control the feeding speed of the magnetic tape. Thus, the relative speed with respect to the magnetic head mounted on the rotary drum can be precisely made substantially constant.

Further, in this configuration, since a memory for speed control is not required and it is not necessary to monitor the time from the start of high speed search, the structure of the speed control unit can be simplified.

It is more preferable to configure the tape speed command generation circuit 113 as shown in FIG. 3 because the tape feed speed followability can be improved. The operation of the tape speed command generation circuit 113 will be described below.

The speed converting means 201, when performing a high speed search,
The speed command value of the magnetic tape is determined and output from the drum rotation speed ω _d detected moment by moment. Speed conversion means 201
The output from is differentiated by the differentiating means 202 and a value proportional to the slope up to the target speed is output. Adder 203
Is the output from the differentiating means 202 and the speed converting means 20.
Add the output from 1. Here, the added result is sent to the reel drive control device 114.

The validity of the operation of the speed command generating circuit 113 will be described below using mathematical expressions. Since the speed control system in the magnetic tape can be generally approximated by a first-order lag system, the transfer function of the tape speed Vt with respect to the speed command Ei is expressed by the following mathematical expression (1).

Vt / Ei = a / (S + a) where a indicates a pole. (1) When a speed command Ei (Ei = m × t where the inclination is m) that linearly rises up to the target speed in proportion to the time t is input to the speed control system expressed by the mathematical expression (1), the tape speed V
t becomes m × t−m × (1-exp (−a × t)) / a, and m × (1-exp (−a ×) with respect to the speed command m × t.
The velocity deviation of t)) / a remains. Therefore, as the speed command Ei, a value (m ×
When t + r) is newly set as the target speed, the tape speed Vt is expressed by the following relational expression.

Vt = r × (1−exp (−a × t)) + m × t −m × (1−exp (−a × t)) / a (2) The offset r is r = from the equation (2). When the tape velocity Vt is set to satisfy the relational expression of m / a, Vt = m × t, and it becomes possible to rise in proportion to time. Therefore, by setting the differential gain K1 of the differentiating means 202 to K1 = 1 / a, the followability of the magnetic tape speed control system is improved, and more accurate speed control with a small relative speed error becomes possible. Tape speed command generation circuit 11 at this time
As shown in FIG. 4, the outline of the output command 3 is such that the offset m / a is added when the speed command rises and the offset m / a is subtracted when the speed command falls.

As described above, by controlling the tape feeding speed by using the differentiating means, it is possible to further improve the followability of the magnetic tape feeding speed to the speed command value.

It should be noted that here, the description has been given of the rising of the high speed search in the FF direction, but it is needless to say that the speed can be similarly controlled at the high speed search in the REW direction and at the falling.

(Second Embodiment) FIG. 5 is a block diagram showing the structure of a speed controller of a magnetic recording / reproducing apparatus according to a second embodiment of the present invention. In this magnetic recording / reproducing apparatus,
The feeding speed of the magnetic tape is controlled independently. That is, the tape feeding speed is not controlled according to the actually measured rotation speed of the rotating drum. Hereinafter, the present embodiment will be described with reference to FIG. 5, but the description of the same parts as those in the first embodiment will be omitted.

The tape speed command generator 30 shown in FIG.
As shown in FIG. 6, reference numeral 1 includes a memory (storage means in the claims) 302 and a memory reading unit (memory reading means in the claims) 303. In the memory 302, a plurality of predetermined times from the start of rising to the end of rising of the rotational speed of the rotary drum, which is rotationally controlled by torque control, and from the start of falling to the end of falling, and the rotations at the predetermined times. The feeding speed of the magnetic tape corresponding to the rotation speed of the drum (the relative speed is constant) is stored. The memory reading unit 303 reads the magnetic tape feeding speed from the memory 302 at the predetermined time and outputs it to the reel drive controller 114.

The operation of this magnetic recording / reproducing apparatus will be described in more detail below.

First, a search start command from the input terminal 101 is input to the tape speed command generator 301 and the torque command generation circuit 102.

Then, the rotary drum is rotationally driven by torque control as described in the first embodiment.

At this time, the tape speed command generator 301
The memory reading unit 303 of the above measures the time from the start of the high speed search, and when the time coincides with the time stored in the memory 302, the magnetic tape feeding speed at that time is read from the memory 302 and the speed is calculated. It is output to the reel speed control device 114 as a speed command value. The reel speed control device 114 and the tape speed detection device 115 control so that the magnetic tape feed speed becomes the speed command value.

As described above, in the present embodiment, the memory 302 causes the magnetic tape feed speed for maintaining a constant relative speed between the magnetic tape and the magnetic head mounted on the rotating drum from the start of high-speed search. The time is stored together with the time, and when the high speed search is started, the rotating drum is subjected to torque control and the magnetic tape is run so as to have the feeding speed at that time stored in the memory 302. Therefore, even during a high speed search, the relative speed of the magnetic tape with respect to the magnetic head mounted on the rotary drum can be made substantially constant. Further, the required storage capacity of the memory can be reduced as compared with the case where both the rotation speed of the rotary drum and the feeding speed of the magnetic tape are stored in the memory as in the conventional case.

Further, the speed command value stored in the memory 302 is used as the magnetic tape feed speed when the magnetic tape runs at a constant relative speed with respect to the rotating drum, and the magnetic tape feed speed at that time. If a value that is proportional to the differential value is added to the value, the followability of the magnetic tape feed speed to the speed command value is improved, and more accurate speed control with a small relative speed error becomes possible.

[0059]

According to the present invention, the rotating drum is rotated by torque control at the time of rising and falling during high-speed search of the rotating speed of the rotating drum, and is rotated by speed control in the steady state. Since the magnetic tape is run according to the rotation speed of the rotating drum or the speed command value stored in the memory, a magnetic head mounted on the rotating drum is used by using a device having a simple structure. The relative speed with respect to the magnetic tape can be made substantially constant.

By setting the speed command value of the magnetic tape feed speed to a value obtained by adding the feed speed corresponding to the rotation speed of the rotary drum and a value proportional to the differential value of the magnetic tape feed speed. The followability of the magnetic tape to the speed command value is improved, and more precisely, the relative speed between the magnetic head mounted on the rotating drum and the magnetic tape can be made substantially constant.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration example of a speed control unit of a magnetic recording / reproducing apparatus of a first embodiment.

FIG. 2 is a waveform showing a rising characteristic of a rotation speed of a rotating drum.

FIG. 3 is a block diagram showing a configuration example of a tape speed command generation circuit in FIG.

4 is a schematic diagram showing an example of an output of the tape speed command generation circuit of FIG.

FIG. 5 is a block diagram showing a configuration example of a speed control unit of the magnetic recording / reproducing apparatus of the second embodiment.

FIG. 6 is a block diagram showing a configuration example of a tape speed command generation circuit in FIG.

FIG. 7 is a diagram schematically showing the scanning loci of the head during normal reproduction and 10 × speed reproduction.

FIG. 8 is a block diagram showing a configuration of a speed control unit of a conventional magnetic recording / reproducing apparatus.

FIG. 9 is a ramp response waveform showing the rising characteristics of the rotation speed of a conventional rotating drum.

[Description of Reference Signs] 103 torque control device 105 drum speed control device 107 control mode switching device 108 switch 113 tape speed command generation circuit 114 reel system drive control device 116 drum motor drive unit

Claims (6)

[Claims] 1. A magnetic tape is fed by a magnetic tape feeding unit, and a rotary drum is rotated by a drum motor to move the magnetic tape relative to a magnetic head mounted on the rotary drum. In a magnetic recording / reproducing apparatus for recording / reproducing a signal on / from a magnetic tape and searching for an absolute address etc. recorded on the magnetic tape at a high speed, a rotation speed detecting means for detecting a rotation speed of a rotating drum, and the rotation during the high speed search A torque control unit that controls and rotates the drum motor so that the torque of the drum motor substantially matches a predetermined torque when the rotation speed of the drum rises and falls, and a detection by the rotation speed detection unit. Based on the result, the rising operation of the rotation speed of the rotary drum at the time of high-speed search and The end of the falling operation is judged, and the drum motor is controlled so that the rotation speed of the rotating drum becomes substantially constant after the rising operation of the rotating speed of the rotating drum and after the ending of the falling operation. Rotation speed control means for rotating, and a speed command value of a magnetic tape feeding speed for maintaining a constant relative speed between the magnetic head mounted on the rotating drum and the magnetic tape at the time of high-speed search. A magnetic recording / reproducing apparatus comprising: a feed speed commanding means for outputting to a unit. 2. The magnetic recording / reproducing apparatus according to claim 1, wherein the speed command value output by the feed speed command means is a relative speed between the magnetic head mounted on the rotary drum and the magnetic tape. A magnetic recording / reproducing apparatus, which is a value obtained by adding a feeding speed of the magnetic tape for maintaining a constant value and a value proportional to a differential value of the feeding speed of the magnetic tape. 3. The magnetic recording / reproducing apparatus according to claim 1, wherein the feed speed commanding means is mounted on the rotary drum based on the rotation speed detected by the rotation speed detecting means. A magnetic recording / reproducing apparatus comprising: speed conversion means for obtaining a feeding speed of the magnetic tape so that a relative speed between the magnetic tape and the magnetic tape becomes constant. 4. A magnetic tape is fed by a magnetic tape feeding unit, and a rotary drum is rotated by a drum motor to move the magnetic tape relative to a magnetic head mounted on the rotary drum. In a magnetic recording / reproducing apparatus for recording / reproducing a signal on / from a magnetic tape, a rotation speed detecting means for detecting a rotation speed of a rotating drum, and a drum motor of the drum motor at the time of rising and falling of the rotating speed of the rotating drum during a high speed search. Torque control means for controlling and rotating the drum motor so that the torque is substantially equal to a predetermined torque, and based on the detection result of the rotation speed detecting means, the rotation speed of the rotating drum during high-speed search The end of the rising operation and the falling operation is judged, and the rotation speed of the rotary drum rises. After the operation is completed and after the falling operation is completed, the rotation speed control means for controlling and rotating the drum motor so that the rotation speed of the rotary drum becomes a substantially constant speed, and the feed speed command means are high-speed search. From the rise to the end of the fall of the rotation speed of the rotating drum, and a plurality of predetermined times from the fall to the end of the rise, and the speed command value according to the rotation speed of the rotary drum at that time. And a memory reading unit for reading the speed command value from the storage unit and outputting the speed command value to the tape feeding unit when the time from the start of the high speed search reaches the predetermined time. A magnetic recording / reproducing apparatus characterized by the above. 5. The magnetic recording / reproducing apparatus according to claim 4, wherein the storage means stores the magnetic tape for maintaining a constant relative speed between the magnetic head mounted on the rotary drum and the magnetic tape. A magnetic recording / reproducing apparatus, which is a means for storing a speed command value obtained by adding a feeding speed and a value proportional to a differential value of the feeding speed of the magnetic tape. 6. The magnetic tape is fed by a magnetic tape feeding section, and the rotary drum is rotated by a drum motor to move the magnetic tape relative to a magnetic head mounted on the rotary drum. In a speed control method at the time of high-speed search of a magnetic recording / reproducing apparatus for recording / reproducing a signal on / from a magnetic tape, the drum motor is made to substantially match a predetermined torque when the rotational speed of the rotating drum rises and falls. And controlling the rotation of the drum motor to determine the end of the rising and falling operations of the rotation speed of the rotating drum during high-speed search, and after the completion of the rising operation of the rotation speed of the rotating drum during high-speed search. And after the falling operation is completed, the rotation speed of the rotary drum is substantially constant. So that,
A speed control method comprising rotating the drum motor.