JP2869289B2 - Magnetic recording / reproducing device - Google Patents

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 using a magnetic tape, and more particularly to a motor torque of a magnetic recording / reproducing apparatus which can drive a magnetic tape at a constant speed only by a reel motor without using a capstan motor or the like. The present invention relates to a technique for reducing speed unevenness caused by ripples and the like.

[0002]

2. Description of the Related Art Conventionally, in a magnetic recording and reproducing apparatus using a magnetic tape, the magnetic tape is driven at a constant speed by pinching a magnetic tape with a pinch roller pressed against the capstan via the capstan and the magnetic tape. It is realized by rotating at a constant speed. Further, it is necessary to wind the sent magnetic tape around a reel, but since the radius of the reel changes with time, the rotation speed of the reel also changes with time. Therefore, when the capstan shaft and the reel shaft are driven by one drive motor, a slip mechanism has to be provided in the reel shaft drive system. Also, besides driving at a constant speed, a function such as fast-forwarding of the tape is also necessary, so it is necessary to switch the deceleration rate from the motor to the reel system between the case of sending the magnetic tape at a constant speed and the case of fast-forwarding,
A complicated mechanism was required. Further, it is necessary to drive the tape at a constant speed during recording and reproduction, and to drive the tape at a tape speed several times to several tens times the normal speed during fast forward.

Further, if the apparatus is compatible with auto-reverse, a capstan, a pinch roller and the like are required for forward and reverse, respectively, and a switching mechanism for each mode such as reproduction, fast forward, and rewind is also required. For this reason, it is realized by using a complicated mechanism composed of an extremely large number of components, and there is a limit in reducing the weight and cost of the drive system. On the other hand, conventionally, the tape speed is detected using a magnetic tape speed detecting means, and the rotation speed of the reel is controlled based on the information, so that the number of parts can be reduced at a constant speed without using a capstan or the like. It constituted a tape running mechanism capable of realizing tape feeding. For example, JP
0-150410, JP-A-57-117152,
The speed detecting means is configured to use a speed detecting roller.

[0004]

The above prior art has the following problems. In this type of magnetic recording / reproducing apparatus, it is necessary to run the tape speed stably during recording and reproduction.
% (JIS, RMS, no audibility correction). The conventional method of driving a magnetic tape at a constant speed with a reel motor without using a capstan has a large wow and flutter value, especially when using a tape cassette with a relatively large load. It was impossible. More specifically, the torque ripple, which is proportional to the rotation speed of the reel motor, was dominant in the wow and flutter.

[0005] Also, due to the nature of the reel motor, the number of revolutions changes from the start of winding (BOT) to the end of winding (EOT) of the magnetic tape, so that it has been difficult to reduce torque ripple.

[0006]

SUMMARY OF THE INVENTION In view of the above problems, the control method according to the present invention takes into account a periodic speed error (motor) in a speed control loop in order to reduce the motor torque ripple which causes the problems. And a learning compensator for learning the torque ripple and adding it to the next cycle (delay time) in a feedforward manner. The delay time of the learning compensator is made variable in accordance with the rotation speed of the reel motor. . Further, a filter and an attenuator for band limitation are added to stabilize the learning control, and a means for correcting a variation in delay time due to the addition of the filter and the attenuator is provided.

Further, the control method is characterized in that the value of the attenuator is 1/2 ^N (N is an integer of 0 or more).

[0008]

According to the present invention, the torque ripple of the reel motor causing wow and flutter can be reduced as much as possible, and the capstan required by the conventional mechanism can be reduced. Thus, a magnetic recording / reproducing apparatus capable of controlling wow and flutter with a small constant speed by means of a reel motor having a very small number of parts without a pinch roller, a slip mechanism or the like can be obtained.

Further, by detecting the rotation speed of the reel motor, the torque ripple can be reduced by following the cycle of the torque ripple that changes from BOT to EOT.

Further, the value of the attenuator is set to 1 /
By setting 2 ^N (N is an integer of 0 or more), the operation by the attenuator can be performed by bit shift, the operation time and the circuit scale can be reduced, and this control is performed by CP.
The processing can be performed in U, and an inexpensive magnetic recording / reproducing apparatus can be obtained.

[0011]

【Example】

(Embodiment 1) An embodiment based on the first invention will be described below with reference to the drawings.

FIG. 1 shows a learning process in which a periodic speed error generated by a motor torque ripple or the like is learned in a speed control loop of a reel motor according to the present invention and is added to the next cycle (delay time) in a feedforward manner. FIG. 3 is a block diagram of a magnetic recording / reproducing apparatus which adds a compensator and changes the delay time according to the rotation speed of a take-side reel. FIG.
, 1 is a magnetic tape, 2 is a take-up reel (hereinafter, take reel), 3 is a supply reel (hereinafter, supply reel), 4 is a tape guide, 5 is a take-side reel motor (hereinafter, reel motor), and 7 is pressure. With a pad, the magnetic tape 1 is guided from a supply reel 3 to a take reel 2 by a tape guide 4 and wound thereon. The magnetic tape 1, take reel 2, and supply reel 3 are housed in the same cassette case (not shown).

During the recording / reproducing operation of the magnetic recording / reproducing apparatus, the magnetic tape 1 is running at a constant speed from the supply reel 3 to the reel by the driving force of the reel motor 5 in the direction of arrow 6 in the figure. The supply reel 3 is also provided with another reel motor, but is omitted because it is not directly related to the present invention. On the other hand, the magnetic head 8 records a signal on the magnetic tape 1 or reproduces a signal from the magnetic tape 1 by sandwiching the running magnetic tape 1 with the pressure pad 7 inserted in the cassette case. Reference numeral 9 denotes a signal processing unit which applies a predetermined process to a signal read from the magnetic tape or a signal recorded on the magnetic tape 1. The signal processing section 9 mainly processes voice, but is not limited to this. Next, the speed control loop will be described.

Since speed control is generally known, it will be briefly described. Reference numeral 10 denotes a speed detector of the magnetic tape 1, 12 denotes a comparison circuit, 13 denotes a target value, 14 denotes a phase compensation circuit, and 15 denotes a motor driver. The speed detecting unit 10 is constituted by a rotating roller and a rotary encoder, and outputs the speed of the magnetic tape 1 as a pulse. Reference numeral 11 denotes a waveform shaping circuit, which is configured by an amplifier or the like, shapes a signal obtained from the speed detection unit 10 into a predetermined waveform, and outputs the waveform. Reference numeral 12 denotes a comparison circuit.
Numeral 2 compares the number of pulses input at a fixed time with the target value 13 and outputs an error signal.

Reference numeral 14 denotes a phase compensation circuit. Reference numeral 15 drives the next-stage reel motor in accordance with the signal input by the motor driver. Since the speed control loop is configured as described above, the magnetic tape 1 is driven at a constant speed because the reel motor is controlled so that the number of pulses from the speed detection unit always becomes the target value. Next, the learning control will be described. A learning compensator 20 is indicated by a broken line in the figure. The learning control unit 20 includes a delay circuit 21 having a delay time L described later, as shown in the figure, and stores the output value of the comparison circuit 12 and adds the output value to the output value of the comparison circuit 12 after L time. This is represented by Equation 1 when represented by a transfer function.

[0016]

(Equation 1)

Here, s is a complex variable in the Laplace transform.

Since the effects of the learning control described above have been described in many documents, a detailed description thereof will be omitted here.
For example, there are IEEJ Transactions C, 55-7, "Highly Accurate Control in Repetitive Operation of Proton Synchrotron Electromagnet Power Supply".

FIG. 2 shows a result of simulating the transfer characteristic of the learning compensator 20. In the figure, the solid line is the gain, and the chain line is the phase. Here, assuming that the torque ripple of the reel motor occurs at 10 times the motor rotation speed, the delay time L is set to the reel rotation speed 0.84 corresponding to BOT.
A case where the period is set to 1 / 8.4 [sec] corresponding to a frequency 8.4 [Hz], which is ten times the [Hz], is shown.
The reason why the delay time L is set to a cycle corresponding to ten times the number of rotations of the reel is that the torque ripple of the reel motor 5 used in this embodiment is generated ten times per rotation, and the type of the motor is different. Of course, the multiple is different.

As described above, the delay time L is changed by the reel motor 5.
, The gain characteristic of the loop transfer characteristic can be improved at a frequency that is an integral multiple of the frequency of the torque ripple of the reel motor.
On the other hand, reference numeral 22 denotes a rotation speed detecting unit of the reel motor 2, which reads out a pulse pattern (not shown) attached to the rotor of the reel motor by a photo interrupter (not shown), and generates a pulse proportional to the rotation speed of the motor. It is configured to obtain. Here, the rotation speed of the reel motor 2 is detected by the above-described method. However, the present invention is not limited to this method. For example, a back electromotive voltage of the reel motor 2 may be used.

Reference numeral 23 denotes a circuit for shaping the output from the rotation speed detector 22 into a predetermined waveform, and is constituted by an amplifier and the like. Numeral 24 calculates the rotation speed of the reel motor 5 from the signal input by the rotation speed calculation circuit. Reference numeral 25 denotes a delay time calculation circuit which calculates a cycle corresponding to the ripple of the reel motor 5 from the information obtained by the rotation speed calculation circuit 24 to obtain a delay time L of the delay circuit 21. For example, the cycle is calculated as a reciprocal of ten times the rotation speed of the reel motor. Therefore, the delay time can follow the rotation speed of the reel motor from BOT to EOT. Further, in the present embodiment, the configuration is such that the information of one cycle before is learned, but for example, the system and control, vol. 31, no5, 1987
A multi-period learning compensator may be used as described in "Consideration of disturbance suppression of control system using iterative learning compensator and proposal of multi-period learning compensator". The transfer function of the multi-period learning compensator is shown in Equation 2 below.

[0022]

(Equation 2)

Here, k _i is a coefficient, preferably k _i = 1
/ N. n is the multiplicity (2, 3, 4,...).

In this case, as described in the above document, a decrease in the gain of the transfer characteristic of the learning compensator outside the delay time is suppressed, and the control characteristic is improved.

Since the delay time L of the delay circuit 21 is calculated according to the change in the rotation speed of the reel motor 5 with the above configuration, the BO of the reel motor 5 is
From T to EOT, it is possible to always work to reduce the ripple, and it is possible to reduce wow and flutter.

(Embodiment 2) Next, an embodiment based on the second invention will be described with reference to the drawings.

FIG. 3 shows a periodic speed error generated by a motor torque ripple or the like in the speed control loop of the reel motor according to the second embodiment of the present invention, and feedforward to the next period (delay time). FIG. 4 is a block diagram of a magnetic recording / reproducing apparatus in which a learning compensator to be added is added, and a filter for band limitation and an attenuator are provided in a loop of the learning compensator. In the figure, the same components and circuits as those described in the first embodiment are denoted by the same reference numerals, and description thereof is omitted. In the figure, reference numeral 20 denotes a learning compensator according to the present embodiment, which comprises a delay circuit 21, a filter 27 and an attenuator 28. The filter 27 limits the band of the learning compensator. The filter 27 limits the gain of a region other than the band including the periodic speed error (motor torque ripple) to secure a gain margin of the speed control system. .

For example, a sampling holder (sampling frequency = 84 [Hz]) as a low-pass filter
Is used. Next, the attenuator 28 is provided to improve the phase characteristics. As a result, in the learning compensation circuit of the first embodiment, as shown in FIG. 2, the stable range of the speed control system allows only a phase delay of ± 90 ° or less to the controlled object, and thus the control system having the first-order or longer delay element. In this case, the system becomes unstable, but this disadvantage can be improved. For example, if the value of the attenuator 28 is set to 1/2, ± 150 °
The phase delay can be tolerated up to this, and the speed control system can be stabilized. The transfer function of the learning compensator according to the present embodiment is shown in Equation 3 below.

[0029]

(Equation 3)

Here, K is the value of the attenuator 28, F
(s) is the transfer coefficient of the filter 27.

In FIG. 4, the delay time L is set to 1 / 8.4 [sec] as in the first embodiment, and the sampling holder (sampling frequency = 84 [H]) is used as the filter 27.
z]), and shows the result of simulating the transfer characteristics when the value of the attenuator 28 is １ ／. Compared to FIG. 2, the phase characteristics are improved, and the gain in the high frequency range is limited.

With the above configuration, stabilization can be achieved even in a control system having a first-order or more phase delay.

(Embodiment 3) Next, an embodiment based on the third invention will be described with reference to the drawings.

FIG. 5 is a diagram for explaining a periodic speed error generated by a motor torque ripple or the like in the speed control loop of the reel motor according to the third embodiment of the present invention, and feedforwarding the next period (delay time). In a magnetic recording / reproducing apparatus in which a learning compensator to be added in the above is added, and a band-limiting filter and an attenuator are provided in the loop of the learning compensator, the time constant of the band-limiting filter is set according to the rotation speed of the reel. It is a block diagram of a variable magnetic recording / reproducing device. In the figure, the same components and circuits as those described in the first and second embodiments are denoted by the same reference numerals, and description thereof will be omitted. In the figure, reference numeral 30 denotes a filter constant calculation circuit which calculates a filter constant according to the output value from the rotation speed calculation circuit 24. Reference numeral 27 denotes a band limiting filter of the learning compensator, which changes the filter constant according to the value obtained by the filter constant calculation circuit 30.

With the above configuration, the filter constant for the band limiting filter 27 of the learning compensator of this embodiment can be varied according to the rotation speed of the reel.
In the OT, the rotation of the reel 31 is fast, and the motor torque ripple is generated at a high frequency. Therefore, the cutoff frequency of the filter 27 is set high (the sampling frequency of the sampling holder is increased). The motor torque ripple is generated at a low frequency, and the cutoff frequency of the filter 27 can be set low (the sampling frequency of the sampling holder can be lowered). Therefore, the constant of the filter 27 of the learning compensator is always optimized from BOT to EOT.

(Embodiment 4) Next, an embodiment based on the fourth invention will be described with reference to the drawings.

FIG. 6 shows a periodic speed error generated by a motor torque ripple or the like in the speed control loop of the reel motor according to the fourth invention of the present invention, and feedforward to the next period (delay time). In a magnetic recording / reproducing apparatus in which a learning compensator to be added is added and a filter for band limitation and an attenuator are provided in the loop of the learning compensator, a correction coefficient is applied to the delay time obtained from the delay amount calculating circuit 25. FIG. 3 is a block diagram of a magnetic recording / reproducing apparatus in which a delay time has been corrected by using FIG. In the figure, the same components and circuits as those described in the previous embodiment are denoted by the same reference numerals, and description thereof will be omitted. In the figure, reference numeral 32 denotes a correction coefficient, which corrects the delay time by multiplying the delay time L obtained by the delay time calculation circuit 25 based on the rotation speed of the reel 2 by a predetermined correction coefficient Z.

Next, the correction coefficient will be described in detail. FIG. 4 shows the transfer characteristic of the learning compensator 20 described above. As described above, the transfer characteristic of the learning compensator is characterized in that the gain is increased at an integral multiple of the delay time L, that is, the frequency corresponding to the motor torque ripple. As described above, when a filter 27 for band limitation is provided in the delay time for stabilizing the control system, a phenomenon occurs in which the delay time L shifts. For example, the position indicated by ↓ in FIG.
4 times the frequency component (8.4 [Hz]) (3
3.6 [Hz]), but the peak of the actual gain is shifted to a value lower than the position of ↓.
The effect of this shift is not a problem when the shift amount is small, but when the shift amount is large as shown in FIG. 4, the gain at the position ↓ is considerably low, and the effect of the learning compensator does not appear in this state.

This is because the band-limiting filter 27 exists in the control loop of the learning compensator, and the transfer characteristic of the learning compensator shifts due to the influence of the transfer characteristic of the filter 27. Therefore, the shift amount naturally affects the transfer characteristics of the filter 27 and the delay circuit 21. FIG. 7 shows the transfer characteristic of the learning compensator when the value of the correction coefficient 32 is 0.966. The peak of the gain has shifted to 33.6 [Hz]. By introducing the correction coefficient in this way, the peak position of the gain of the transfer characteristic of the learning compensator can be corrected so as to be an integral multiple of the delay time L, and the above-described effect of the learning compensator can be obtained.

(Embodiment 5) Next, an embodiment based on the fifth invention will be described. Table 1 shows the results obtained by simulating the correction coefficients for the BOT and EOT in Example 4 described above. The simulation conditions are such that a sampling holder is used for the filter 27, the sampling frequency is fixed, and the multiplicity of the learning compensator is determined.

[0041]

[Table 1]

As shown in Table 1, the correction coefficients are different from BOT to EOT, and in order to obtain the optimum effect of the learning compensator from BOT to EOT, it is necessary to change the correction coefficient according to the rotation speed of the reel. I understand. FIG. 8 shows learning compensation in which a periodic speed error (motor torque ripple) is learned and added to the next period (delay time) in a feedforward manner in the speed control loop of the reel motor according to the fifth invention of the present invention. In a magnetic recording / reproducing apparatus in which a filter for band limitation and an attenuator are provided in the loop of the learning compensator, a delay time is obtained by multiplying the delay time of the learning compensator by a correction coefficient corresponding to the rotation speed of the reel. FIG. 3 is a block diagram of a magnetic recording / reproducing apparatus in which is corrected.

In the figure, the same components and circuits as those described in the previous embodiment are denoted by the same reference numerals, and description thereof will be omitted. Reference numeral 40 denotes a correction coefficient calculation circuit which calculates the value of the correction coefficient in accordance with the output value of the rotation speed calculation circuit 24 or obtains it from a correction coefficient table which is calculated in advance by simulation or the like as shown in Table 1 and tabulated. By using the present invention configured as described above, as described above, from BOT to E
An optimum correction coefficient is always obtained over OT. Therefore, the learning compensator is always optimized and the torque ripple can be effectively reduced.

Embodiment 6 Next, an embodiment based on the sixth invention will be described. Table 2 shows that the sampling period of the sampling holder is set to one of the delay time in the fourth embodiment.
The results are shown as / 10 times, 1/20 times, and 1/40 times, and the correction coefficient is obtained by simulation for each multiplicity of the learning compensator.

[0045]

[Table 2]

The results of the simulation in Table 2 are valid under the above conditions, and the correction coefficient must be obtained in advance by simulation or the like as in the present embodiment. As described above, the correction coefficient is uniquely obtained by setting the sampling period to n times the delay time, and the value of the correction coefficient is set to BO.
It can be fixed regardless of the delay time that changes from T to EOT. FIG. 9 shows the learning of a periodic speed error (motor torque ripple) in the speed control loop of the reel motor according to the sixth invention, and the next period (delay time).
And a learning compensator that adds feedforward to
FIG. 3 is a block diagram of a magnetic recording and reproducing apparatus in which a constant of a band limiting filter is varied according to a delay time in a magnetic recording and reproducing apparatus provided with a band limiting filter and an attenuator in a loop of the learning compensator.

In the figure, the same components and circuits as those described in the previous embodiment are denoted by the same reference numerals, and description thereof will be omitted. Reference numeral 41 denotes a filter constant calculation circuit which calculates the filter constant of the filter 27 in accordance with the output value from the delay time calculation circuit 25 or obtains the filter constant from a table prepared in advance as shown in Table 2. For example, if the filter 27 is composed of a sampling holder, the sampling period of the sampling holder is calculated to be n times the delay time L obtained by the delay time calculation circuit 25 as described above. According to the present invention configured as described above, the correction coefficient can be fixed from BOT to EOT, and the circuit configuration can be simplified. In this embodiment, a sampling holder is used as the filter 27. However, any filter may be used, and the time constant of the filter may be set to be n times the delay time L.

FIG. 10 shows the effect of the use of the magnetic recording / reproducing apparatus of the present invention as measured by a wow flutter meter. The upper part in the figure shows the wow and flutter FFT when the magnetic tape is driven at a constant speed by the conventional reel motor.
As a result of the frequency analysis, the lower part shows the FF of the wow and flutter when the magnetic recording / reproducing apparatus according to the present invention is used.
It is a frequency analysis result by T. The portion indicated by 部分 in the figure is the torque ripple, but the value in the lower row is smaller than the value in the upper row. Thus, it is clearly understood that the use of the magnetic recording / reproducing apparatus of the present invention can reduce wow and flutter.

(Embodiment 7) In Embodiment 2, the phase characteristic is improved by the operation of setting the value of the attenuator to 1/2 ^N (N is an integer of 0 or more). FIG. 11 shows the configuration of the attenuator in this embodiment. FIG.
The attenuator is constituted by a shift register 50 as shown in FIG.
Can be easily performed with the value of ^NN .

For example, when N = 0, the phase delay due to the learning control is 90 ° at the maximum, and the stable range of the speed control system is limited to a phase delay of ± 90 ° or less at most for the controlled object. A control system with elements becomes an unstable system. However, if N = 1 is set, as described in the second embodiment, the phase delay can be allowed up to ± 150 °, and the speed control system can be stabilized.

It is obvious that the attenuator is constituted by a shift register on the premise that the signal processing system of the present invention is constituted by a digital circuit.

This embodiment can be similarly applied to Embodiments 3, 4, 5, and 6 having an attenuator.

[0053]

According to the present invention, a delay time of a learning compensator for learning a periodic disturbance amount or a speed error (motor torque ripple) and adding it to the next cycle in a feedforward manner is set in a speed control loop. Since the speed is variable according to the number of rotations of the motor, periodic unevenness in the speed of the magnetic recording / reproducing apparatus, which can drive the magnetic tape at a constant speed only by the reel motor without using the capstan motor, etc. Motor torque ripple) can be reduced, and it can be used for audio use.

Further, a filter and an attenuator for band limitation are added to stabilize the learning control, and a means for compensating for a delay time variation due to the addition of the filter and the attenuator is provided. The effect of the learning compensator is obtained.

Further, the value of the attenuator is set to 1/2 ^N
As a result, the operation is simplified, a large-scale arithmetic circuit such as a coprocessor is not required, and the control system is constituted by a small-scale CPU. Therefore, the effect of the learning compensator of the magnetic recording / reproducing apparatus can be obtained at low cost. Can be

[Brief description of the drawings]

FIG. 1 is a block diagram of a magnetic recording / reproducing apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating transfer characteristics of a learning compensator according to the first embodiment of the present invention.

FIG. 3 is a block diagram of a magnetic recording / reproducing apparatus according to a second embodiment of the present invention.

FIG. 4 is a diagram illustrating a transfer characteristic of a learning compensator according to a second embodiment of the present invention.

FIG. 5 is a block diagram of a magnetic recording / reproducing apparatus according to a third embodiment of the present invention.

FIG. 6 is a block diagram of a magnetic recording / reproducing apparatus according to a fourth embodiment of the present invention.

FIG. 7 is a diagram illustrating transfer characteristics of a learning compensator according to a fourth embodiment of the present invention.

FIG. 8 is a block diagram of a magnetic recording and reproducing apparatus according to a fifth embodiment of the present invention.

FIG. 9 is a block diagram of a magnetic recording and reproducing apparatus according to a sixth embodiment of the present invention.

FIG. 10 is a frequency analysis diagram of a wow and flutter of a magnetic recording and reproducing apparatus according to a sixth embodiment of the present invention.

FIG. 11 is a configuration diagram of an attenuator according to a seventh embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 magnetic tape 2 take reel 3 supply reel 5 reel motor 10 speed detector 20 learning compensator 21 delay circuit 22 rotation speed detector 25 delay time calculation circuit 27 filter 28 attenuator 30 filter constant calculation circuit 32 correction coefficient 40 correction coefficient calculation circuit

Continuation of the front page (72) Inventor Toru Okuda 22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka Inside Sharp Corporation (58) Field surveyed (Int.Cl. ⁶ , DB name) G11B 15/46

Claims (7)

(57) [Claims] 1. A learning compensator for learning a periodic speed error and adding it to a next period (delay time) in a feedforward manner in a reel motor speed control loop, and detects a rotation speed of the reel motor. A magnetic recording / reproducing apparatus comprising a rotation detecting means, wherein a delay time of the learning compensator is varied according to an output value of the rotation detecting means. 2. A learning compensator for learning a periodic speed error and adding it to a next cycle (delay time) in a feedforward manner in a reel motor speed control loop, and detects a rotation speed of the reel motor. In a magnetic recording / reproducing apparatus having rotation detecting means, wherein a delay time of the learning compensator is made variable according to an output value of the rotation detecting means, a filter and an attenuator for band limitation are provided in a control loop of the learning compensator. A magnetic recording / reproducing apparatus characterized by adding. 3. The filter according to claim 2, wherein the time constant of the band-limiting filter according to claim 2 is varied according to the output value of the rotation detection means of the reel motor. Magnetic recording and reproducing device. 4. The magnetic recording and reproducing apparatus according to claim 2, wherein the delay time of the learning compensator is multiplied by a delay time correction coefficient. 5. The magnetic recording and reproducing apparatus according to claim 2, wherein the delay time of the learning compensator is multiplied by a delay time correction coefficient,
3. The magnetic recording / reproducing apparatus according to claim 2, wherein the value of the delay time correction coefficient is varied according to the output value of the rotation detecting means according to claim 2. 6. The magnetic recording / reproducing apparatus according to claim 2, wherein the time constant of the band-limiting filter according to claim 2 is n times the delay time calculated by the delay amount calculating circuit. apparatus. 7. The magnetic recording and reproducing apparatus according to claim 2, wherein the value of the attenuator is 1/2 ^N
7. The magnetic recording / reproducing apparatus according to claim 2, wherein N is an integer of 0 or more.