JP3282218B2 - Recording / playback 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 recording / reproducing apparatus such as a video tape recorder (VTR) having a PWM control circuit suitable for controlling the speed of a capstan motor or a drum motor.

[0002]

2. Description of the Related Art FIG. 3 is a block diagram showing a configuration of a capstan servo device used in a conventional VTR. In a steady state, a portion for controlling a capstan motor at a reference speed and a capstan motor standing at a reference speed. It consists of raising parts.

First, a portion for controlling the capstan motor to a reference speed in a steady state will be described.

The rotation speed of the capstan motor 1 is detected by a frequency generator (FG) 2 and input to a speed detection circuit 3. The speed detection circuit 3 detects the rotation speed of the capstan motor 1 by measuring the output pulse interval of the frequency generator 2. The output of the speed detection circuit 3 is compared with a reference speed signal (SPEED · REF) in a subtractor 4, and the error signal is input to an arithmetic circuit 5. The arithmetic circuit 5 is configured to control the capstan motor 1 based on the error signal.
Is calculated and the register 6 is set. The PWM data set in the register 6 is input to the PWM circuit 8 through the switching circuit 7 set on the N side in a steady state. The PWM circuit 8 generates a PWM pulse having a duty corresponding to the input PWM data. The PWM pulse is supplied to the capstan motor 1 via the low-pass filter 9 and the driver 10. Here, the speed detection circuit 3, the subtractor 4, and the arithmetic circuit 5 are constituted by software of a microcomputer (not shown). With the above configuration, the capstan motor 1 can be controlled to the reference speed in the steady state.

Next, a description will be given of a portion for raising the capstan motor to the reference speed.

For example, in a case where intermittent slow reproduction of about a slow ratio of 1/2 is performed by repeating still reproduction of about two fields and normal reproduction of about two fields, the capstan motor is raised to a reference speed every about two fields. Perform the operation.

In order to perform this operation, the timing controller 11 composed of hard logic forcibly switches the switching circuit 7 to the S side about every two fields, and sets a high level (hereinafter, referred to as S) of the switching circuit 7 to the S side.
PWM data of “H” level) is fixedly input. Therefore, a PWM pulse having a duty corresponding to the "H" level PWM data is supplied to the capstan motor 1 approximately every two fields.

FIGS. 4A and 4B are timing charts showing this operation. FIG. 4A shows a driving voltage supplied to the capstan motor 1, and FIG. 4B shows a rotation speed of the capstan motor 1. At t = t1, the switching circuit 7 is switched to the S side, and the “H” level PWM is applied to the capstan motor 1.
A drive voltage corresponding to the data is supplied, and at t = t2, the switching circuit 7 is switched to the N side, and the capstan motor 1
, A driving voltage corresponding to the PWM data set in the register 7 is supplied. In other words, the startup operation is from t = t1 to t = t2, and the normal operation is after t = t2.

Here, the reason why the hardware logic is used at the time of startup is that it is difficult to perform startup at accurate timing if control is performed by software.

[0010]

In the conventional capstan servo device described above, the "H" level PW
Since the M data is fixedly input to the PWM circuit, fine speed control cannot be performed when the capstan motor starts up, and as shown in FIG. Problems.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems and to provide a recording / reproducing apparatus having a recording / reproducing apparatus and a servo apparatus capable of finely controlling the speed at the time of starting the motor.

[0012]

In order to solve the above-mentioned problems, a recording / reproducing apparatus according to the present invention comprises a PWM data storage means for storing a plurality of PWM data, and a PWM data storage means for storing a plurality of PWM data in accordance with a load condition and an operation mode for the motor. PWM data setting means for setting the PWM data stored in the PWM data storage means for each start-up operation of the motor; PWM data selection means for switching and outputting the plurality of PWM data at a predetermined timing; The PW
PWM of duty corresponding to output of M data selection means
This is provided with a PWM circuit for generating a pulse.

Further, according to the present invention, PWM data corresponding to an error between a rotation speed of a motor and a reference speed is input to a PWM circuit, and the PWM circuit generates a PWM pulse having a duty corresponding to the PWM data to generate the PWM pulse. In a recording / reproducing apparatus including a servo device configured to drive a motor, a PWM data storage unit that stores a plurality of PWM data;
PWM data setting means for setting PWM data stored in the PWM data storage means for each start-up operation of the motor in accordance with a load condition and an operation mode for the motor, and PWM for setting PWM data in the storage means
Data setting means and PWM data selecting means for switching and outputting the plurality of PWM data at a predetermined timing are provided, and the output of the PWM data selecting means is input to the PWM circuit when the motor starts up. It is like that.

[0014]

According to the present invention, PWM data selection means
A plurality of PWM data set for each start-up operation of the motor can be switched at a predetermined timing and supplied to the PWM circuit in accordance with the load condition and the operation mode for the motor stored in the M data storage means.
Therefore, for example, a multi-step PWM pulse can be generated within one field of a video signal.

Further, the present invention provides a method for starting up a motor,
The motor can be driven by a PWM pulse having a duty according to a plurality of PWM data switched at a predetermined timing. So, for example,
Since a multi-step drive voltage can be supplied to the motor within one field of the video signal, fine speed control becomes possible.

[0016]

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

FIG. 1 is a block diagram showing a configuration of a capstan servo device used in a recording / reproducing apparatus according to the present invention. Here, parts corresponding to those in FIG. 3 are given the same numbers.

This embodiment also comprises a portion for controlling the capstan motor at the reference speed in the steady state and a portion for starting the capstan motor at the reference speed in the steady state, as in the above-described conventional example. Since the configuration of the portion for controlling the capstan motor to the reference speed is the same as that of the related art, the description of this portion will be omitted.

In this embodiment, a portion for raising the capstan motor 1 for feeding the tape at a constant speed to the reference speed is constituted by a timing / level controller 12, a level selector 13, a register group 14, and a data setting circuit 15. I have.

The timing / level controller 12
Switching circuit 7 at a predetermined timing
Is forcibly switched to the S side and the level selector 13 is sequentially switched. The level selector 13 is switched under the control of the timing / level controller 12, and selectively outputs the output of the register group 14 to the S side of the switching circuit 7. A register group consisting of n registers is
P for finely controlling the speed of the capstan motor 1
The WM data D1 to Dn are stored. The PWM data setting circuit 15 is configured by software of a microcomputer (not shown) and sets the PWM data D1 to Dn.

FIGS. 2A and 2B are operation timing charts of the capstan servo device to which the present invention is applied. FIG. 2A is a drive voltage supplied to the capstan motor 1, and FIG. Is shown. Hereinafter, the operation of this embodiment will be described with reference to FIGS.

The timing / level controller 12 calculates t
= T3 to t = t4, the switching circuit 7 is forcibly switched to the S side. Further, between t = t3 and t = t4, the level selector 13 is switched to sequentially output the PWM data D1 to Dn of the register group 14 to the S side of the switching circuit 7. As a result, when the capstan motor 1 starts up, an n-level (n = 5 in the figure) drive voltage is supplied as shown in FIG.
As shown in (2), the rotation speed of the capstan motor 1 quickly reaches the reference speed.

Here, the timing / level controller 1
2 is a timing t for switching the switching circuit 7 to the S side.
3 to t4 and the timing of switching the level selector 12 are set by writing in a table in the timing / level controller 12. In addition, the PWM data D1 to
Dn is set by the microcomputer (not shown) as described above. Hereinafter, a setting process of the PWM data D1 to Dn will be exemplified. (1) The PWM data D1 to Dn are set for each rising operation of the capstan motor 1. (2) The PWM data D1 to Dn are set according to the load of the capstan motor 1. As a method of measuring the load,
For example, the tape position is calculated from the number of revolutions of the supply reel and the number of revolutions of the take-up reel. The driving voltage is relatively large at the beginning of the tape because the load is large, and the driving voltage is small at the end of the tape because the load is small. Relatively small,
The temperature is measured by a temperature sensor. If the temperature is low, the driving voltage is relatively large because the load is large, and if the temperature is high, the driving voltage is relatively small because the load is small. (3) PWM data D1 based on the past tape stop position
To Dn. That is, the tape stop position at the time of intermittent slow reproduction is measured, and the current PWM data D1 to Dn are set according to the deviation from the track. (4) Make settings according to the operation mode (slow, FF, etc.) of the VTR.

It should be noted that the present invention is not limited to the above-described embodiment, and various modifications are possible based on the spirit of the present invention, and they are not excluded from the scope of the present invention. For example, the above embodiment relates to speed control of the capstan motor during intermittent slow reproduction, but the present invention can also be applied to drum motor speed control during intermittent slow reproduction. In addition to the speed control during intermittent slow playback, the speed control of the capstan motor when shifting from the pause mode to the recording mode, the speed control of the capstan motor and the drum motor when shifting from the stop mode to the playback mode, The present invention can also be applied to speed control of a reel motor in the FF mode or the rewind mode.

In the above embodiment, the switching of the switching circuit and the level selector is controlled by the timing / level controller. The control data written in the table of the timing / level controller is transmitted to the microcomputer, and the transmitted control data is transmitted to the microcomputer. , The level selector and the output selector may be switched by hardware.

[0026]

As described in detail above, according to the present invention, a multi-step PWM is performed within a predetermined period.
Since a pulse can be generated and a multi-step drive voltage can be supplied when the motor is started, the motor can be started smoothly. For example, when applied to the speed control of a capstan motor of a VTR, a multi-step drive voltage can be supplied within a startup time within one field.

Further, by supplying a drive voltage of a level corresponding to the load of the motor and the past data, a smooth and optimal start-up can be performed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a capstan servo device used in a recording / reproducing apparatus according to the present invention.

FIG. 2 is an operation timing chart of a capstan servo device used in the recording / reproducing apparatus according to the present invention.

FIG. 3 is a block diagram showing a configuration of a capstan servo device used in a conventional recording / reproducing device.

FIG. 4 is an operation timing chart of a capstan servo device used in a conventional recording / reproducing apparatus.

[Explanation of symbols]

1 capstan motor, 8 PWM circuit, 12
Timing / level controller, 13 level selector, 14 register group, 15 data setting circuit

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H02P 5/00-5/26 H02P ^7/ 00-7/34 H02P 1/18

Claims (2)

(57) [Claims] A PWM data storage means for storing a plurality of PWM data, and a PWM data storage means for storing a plurality of PWM data in accordance with a load condition and an operation mode for the motor.
The PWM data storage means for each start-up operation of the motor
PWM data setting means for setting the PWM data stored in the memory, PWM data selecting means for switching and outputting the plurality of PWM data at a predetermined timing, and PWM having a duty corresponding to the output of the PWM data selecting means A recording / reproducing apparatus comprising a PWM circuit for generating a pulse. 2. A PWM circuit according to an error between a rotation speed of a motor and a reference speed is input to a PWM circuit, and the PWM circuit generates a PWM pulse with a duty according to the PWM data to drive the motor. in the recording and reproducing apparatus having a servo device which is adapted, the PWM data storing means for storing a plurality of PWM data, in response to said load status and operating mode for the motor
The PWM data storage means for each start-up operation of the motor
Setting the PWM data stored in the PWM data setting means, wherein the PWM data setting means for setting the PWM data in the storage means, PWM data selection means for outputting the switched at a predetermined timing a plurality of PWM data preparative provided, the said PWM circuit during start-up operation of the motor P
Servo to input the output of WM data selection means
Recording / reproducing device provided with the device .