JPH0664785B2 - Tape speed control circuit - Google Patents

Description

The present invention relates to a tape speed control circuit suitable for application to a speed control system of a digital data recorder operating at high speed.

[Prior Art] For example, as a digital cassette data recorder used for recording various digital data,
Two types of drive systems are known, a reel drive system and a capstan drive system similar to the audio tape recorder.

Recently, attention has been paid to the characteristics of the reel drive system, and data recorders using the former drive system are becoming popular.

When the reel drive system is adopted, the most serious problem is the speed control of the tape running at high speed.

This is because in the case of a data recorder, the tape speed must always be constant even if the tape winding diameter changes.

Conventionally, in order to make the tape speed constant, the following tape speed control circuit has been configured.

First, a special tape is used as the tape used in the data recorder. As shown in FIG. 6, a track TS for tape speed detection is provided in addition to the data tracks T1 and T2, and a reference signal having a predetermined frequency is recorded therein.

In the tape reproducing system, a dedicated magnetic head for this reference signal is attached, and a speed control system is set so that the reproduction frequency becomes constant from the reference signal reproduced by this magnetic head regardless of the tape winding diameter. I was making up.

In addition, when a normal tape used in a commercially available audio tape recorder is used for a data recorder, the tape speed may be detected by a roller or the like that is in contact with the tape when recording / reproducing data.

[Problems to be Solved by the Invention] By the way, when using the above-mentioned special tape, it is necessary to use a dedicated cassette in which a reference signal is recorded as a means for making the tape speed constant. is there.

In addition, since a dedicated magnetic head must be provided to reproduce this reference signal, this complicates the configuration of the data recorder.

Further, when a special tape is used, the magnetic head comes into contact with the tape, and in the case of a normal tape, the roller comes into contact with the tape, which is so-called tape contact type speed detection, which increases the load.

When the load increases, a motor having a large torque is required for the winding motor.

Therefore, if the above-mentioned tape contact type speed detection is not used, a motor with a small torque can be used, which can significantly reduce the cost of the apparatus itself. Also, an attached circuit configuration for recording the reference signal is not necessary.

Therefore, in the present invention, such a conventional problem is simply solved and the tape can be read without a tape contact type speed detecting means such as a magnetic head for reproducing the reference signal or the reference signal. We propose a data recorder that can achieve constant speed.

[Technical Means for Solving Problems] In order to solve the above-mentioned problems, the invention according to claim 1 is provided in association with a dedicated motor for driving the take-up reel. Tape speed detection means, speed control signal storage means for storing a speed control signal for the drive motor, frequency / voltage conversion means for converting the tape speed signal output from the tape speed detection means into a voltage signal, and speed control A tape speed signal related to the tape winding diameter obtained from the tape speed detecting means, which has a comparing means for comparing the speed control signal output from the signal storing means with the voltage signal output from the frequency / voltage converting means. The speed control signal stored in the speed control signal storage means is referred to by the speed control signal storage means, and the tape speed signal is converted into a voltage signal by the frequency / voltage conversion means. The degree control signal and the converted voltage signal are compared by the comparison means, and the comparison result is fed back to the drive motor so that the drive motor always maintains a constant tape speed regardless of the change in the tape winding diameter. It is characterized by being controlled.

In the invention described in claim 2, a mono-multi that converts the tape speed detected by the tape speed detecting means into a constant pulse width, an integrating circuit that integrates the output of the mono-multi, and an integrating circuit A control means for controlling the motor on the tape supply side by the output is provided, and the motor output on the supply side is controlled to decrease toward the end of winding of the tape, regardless of the change in the tape winding diameter. It is characterized by having a constant tape tension.

[Operation] In this configuration, a large number of drive voltages for the winding motor are required to maintain a constant tape speed with respect to a change in the tape winding diameter from the winding start to the winding end on the winding side. In other words, the speed control signal is stored in the storage means in advance.

Which stored data is used depends on the tape speed signal related to the tape winding diameter obtained from the tape speed detecting means. Specifically, it is known in advance which tape speed signal has a certain value and which address speed control signal is referred to, so that the speed control signal corresponding to this tape speed signal is referred to. Will be done.

In this way, the speed of the winding motor is controlled only by using the tape speed detection signal, so that the tape speed is always kept constant regardless of the change in the winding diameter of the tape.

Embodiment Next, an example of the tape speed control circuit according to the present invention will be described.
The case of application to the speed control system of the above data recorder will be described in detail with reference to FIG.

First, in the present invention, since the tape speed is made constant without the reference signal, the tape format of this embodiment is as shown in FIG. by this,
It becomes possible to add data recording tracks and record other signals (control signals, etc.).

Now, in the tape speed control circuit 10 of FIG.
Is a drive motor (supply side motor) on the tape supply side,
1T is a winding side motor. These drive motors 1S,
Any 1T can use a small motor capable of generating a torque as much as required in a normal audio tape recorder.

In this embodiment, a constant tension control system 10B is provided in addition to the constant speed control system 10A, and it is controlled so that the tension is always constant from the winding start to the winding end of the tape.

The reason why constant tension is applied is to stabilize the head touch on the magnetic head of the tape from the beginning to the end of the tape winding, and reduce the occurrence of dropout during recording / reproducing of data.

The constant speed control system 10A will be described.

A tape speed detecting means 2 is provided to detect the tape speed in relation to the winding side motor 1T. As this tape speed detecting means 2, in this example, a frequency generator (F
G) is used.

When the rotational state is detected by magnetic means, a magnet is formed on the rotating disk 2A as shown in the figure, and a magnetic detecting element 2B is arranged so as to face the magnet.

As a result, from the detection element 2B, the winding-side motor 1
The number of revolutions of T, that is, the tape speed of the tape wound on the take-up reel side is detected.

This tape speed detection signal is 1 / m (m
Is a integer, and the divided pulse within a unit time is counted by the counter 4.

Therefore, the count output corresponding to the tape speed is obtained from the counter 4. Since the tape speed and the tape winding amount are in a proportional relationship, the count output shows how much the tape is wound.

The count output is supplied to the tape speed control signal storage means 5. Here, at what tape speed, how much drive voltage should be applied to the winding-side motor 1T to make the tape speed constant is known in advance. The storage means 5 stores data necessary for making the tape speed constant, that is, speed control information to be added to the winding side motor 1T at each point from the winding start to the winding end of the tape.

The relationship between the tape winding amount and the drive voltage required for the winding side motor 1T at that time is as shown by the curve L1 in FIG. Therefore, the value of each drive voltage from the beginning of winding to the end of winding is the data (digital data) for the speed control signal.
Is stored and the data is referred to by the tape speed detection signal. For this reason, as the storage means 5, it is sufficient to use the one having a ROM structure and tabulated.

The speed control signal referred to by the tape speed detection signal is converted into an analog signal by the D / A converter 6, and this is supplied to the motor drive circuit 11.

The drive circuit 11 has an operational amplifier 13, and the analog speed control signal is supplied to the + terminal of the operational amplifier 13 via the resistance voltage dividing circuit 12.

The output of the operational amplifier 13 is applied to the winding-side motor 1T via the complementary connected output transistors Q1 and Q2.

In addition, 14 is a feedback resistor.

Further, in this embodiment, in order to remove the speed fluctuation due to the load fluctuation, the tape speed detection signal is further supplied to the frequency / voltage conversion circuit 15 and the tape speed is converted into a predetermined voltage signal. This is supplied to the negative terminal side of the operational amplifier 13 via the resistor 16.

As a result, the take-up side motor 1T is speed-controlled so that the tape speed becomes constant in consideration of the load fluctuation.

Next, the constant tension control system 10B will be described.

The tape speed detection signal is supplied to the mono-multi 21 so that the pulse width is constant regardless of the speed fluctuation and pulse shaping is performed.

The tape speed detection signal having a constant pulse width is supplied to the integrating circuit 22 composed of the operational amplifier 23 to form an integrated output as shown by the straight line L2 in FIG.

Here, from the beginning of the tape to the end of winding,
An integrated output whose level increases in the negative direction is formed.

The integrated output is supplied to the drive voltage control circuit 24. The control circuit 24 has an operational amplifier 26, and the integrated output is supplied to its + terminal via a level adjusting element 27. This +
Since the constant voltage Vo is applied to the terminal through the level adjusting element 28, the output of the operational amplifier 26 is a drive voltage (the output voltage decreases as the winding end is approached as shown in FIG. 5). A straight line L3) is obtained.

This drive voltage is used by the operational amplifier 3 that constitutes the constant current circuit 30.
1 is supplied to the control transistor Q3, which is further supplied to the control transistor Q3 for current conversion. The supply side motor 1S is connected in series to the current line of the control transistor Q3.

Now, if the rotation torque of the supply side motor 1S is constant,
The smaller the winding diameter of the tape on the supply side reel,
The tape tension increases at the end of winding. If the motor control characteristics shown in FIG. 5 are selected,
As a result, the drive current for the supply-side motor 1S decreases toward the winding end side of the tape, so that constant tension can be achieved by such control.

[Effects of the Invention] As described above, according to the configuration of the present invention, the speed of the winding-side motor is controlled on the basis of the tape speed detection signal, so that the tape speed can always be kept constant.

In this case, according to the present invention, a speed control signal capable of constant speed is stored in advance, and the data is referred to by the tape speed detection signal. Therefore, if the data for the speed control signal is increased, only that much control is performed. The accuracy is improved, which enables highly accurate constant speed control.

Furthermore, the tape speed is converted into a voltage signal, and the winding-side motor is controlled based on the result of comparison with the voltage signal, so that the tape speed is maintained constant even if a load fluctuation occurs in the winding-side motor. It will be possible.

Further, even in the case of speed control, it is not necessary to record the reference signal on the tape as in the conventional case, and it is not necessary to add a dedicated magnetic head for reproducing the reference signal.

Therefore, when the tape speed control circuit according to the present invention is applied to a data recorder, the existing audio tape recorder has a feature that it can be used by slightly changing the specifications.

Therefore, the tape speed control circuit according to the present invention is very suitable when applied to the above-mentioned cassette type digital data recorder.

[Brief description of drawings]

FIG. 1 is a system diagram showing an example in which a tape speed control circuit according to the present invention is applied to a data recorder, FIG. 2 is a tape format used at that time, and FIGS.
FIG. 6 is a characteristic diagram for explaining the operation, and FIG. 6 is a tape format in a conventional data recorder. 10: Tape speed control circuit 10A: Constant speed control system 10B: Constant tension control system 5: Speed control signal storage means 1T: Winding side motor 1S: Supply side motor 2: Tape speed detection means

Claims (2)

[Claims] 1. A tape speed detecting means provided in association with a dedicated motor for driving a take-up reel, a speed control signal storing means for storing a speed control signal for the drive motor, and the tape speed detecting means. The frequency / voltage converting means for converting the tape speed signal output from the tape into a voltage signal is compared with the speed control signal output from the speed control signal storing means and the voltage signal output from the frequency / voltage converting means. Comparing means, the speed control signal stored in the speed control signal storage means is referred to by the tape speed signal related to the tape winding diameter obtained from the tape speed detecting means, and the frequency / voltage converting means is used. The tape speed signal is converted into a voltage signal, and the referenced speed control signal and the converted voltage signal are compared by the comparison means. The comparison result is fed back to the drive motor, and the drive motor is controlled so that the tape speed is always constant regardless of the change in the winding diameter of the tape. Control circuit. 2. A mono-multi for converting the tape speed detected by the tape speed detecting means into a constant pulse width, an integrating circuit for integrating the output of the mono-multi, and an output of the integrating circuit for supplying the tape on the tape supply side. And a control means for controlling the motor, and by controlling such that the motor output on the supply side becomes smaller toward the end of the winding of the tape, a constant tape tension is maintained regardless of the change in the winding diameter of the tape. The tape speed control circuit according to claim 1, wherein the tape speed control circuit is configured as follows.