JPS63302454A - Tape speed control circuit - Google Patents

Abstract

PURPOSE:To always keep tape speed constant, by controlling the speed of a take-up side motor based on a tape speed detecting signal. CONSTITUTION:A large number of driving voltages for a take-up motor 1T required to always set the tape speed constant for the change of the winding diameter of a tape from the start of the winding to the end of the winding of the tape at a take-up side, that is, a speed detecting signal is stored in a storage means 5 in advance. The selection of stored data is decided by a tape speed signal relating to the winding diameter of the tape obtained from a tape speed detecting means 2. Thus, since the speed control of the take-up motor 1T is performed only by using the tape speed detecting signal, constant tape speed can be always obtained in spite of the change of the winding diameter of the tape.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] 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 1 For example, a digital cassette data recorder used to record various digital data is
Two types of drive systems are known: a reel drive system and a capstan drive system similar to audio tape recorders.

Recently, data recorders employing the former drive method have become popular, focusing on the characteristics of the reel drive method.

When employing the reel drive system, the biggest problem is the problem of controlling the speed of the tape running at high speed.

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

Conventionally, in order to maintain a constant tape speed, 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, in addition to the data tracks TI and T2, a track TS for detecting tape speed is provided, and a reference signal of a predetermined frequency is recorded here.

In the tape playback system, a magnetic head dedicated to this reference signal is attached, and a speed control system is controlled based on the reference signal played back by this magnetic head so that the playback frequency remains constant regardless of the tape winding diameter. It was composed.

Furthermore, 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 comes into contact with the tape during data recording/reproduction.

[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 on which a reference signal is recorded as a means for keeping the tape speed constant. be.

Furthermore, in order to reproduce this reference signal, a dedicated magnetic head must be provided, which complicates the configuration of the data recorder.

Roughly speaking, when using special tape, the magnetic head comes into contact with the tape, and when using regular tape, the roller comes into contact with the tape, which is the so-called tape contact type speed detection, which increases the load. .

When the load increases, a winding-side motor with high torque is also required.

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

In view of this, the present invention solves these conventional problems with a simple structure, and allows the tape to be detected without providing a reference signal or a tape-contact type speed detection means such as a magnetic head for reproducing the reference signal. This paper proposes a data recorder that can maintain constant speed.

[Technical Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention provides a tape speed detection means provided in connection with a motor for driving a take-up reel, and a tape speed detection means for this drive motor. a speed control signal storage means in which a speed control signal is stored, and a speed control II times signal stored in the storage means is determined by the tape speed signal related to the tape winding diameter obtained from the tape speed detection means; This referenced speed control signal is characterized in that it is fed back to the drive motor.

[Function] In this configuration, a large number of drives are required for the winding motor to maintain a constant tape speed regardless of changes in the tape winding diameter from the start of tape winding to the end of tape winding on the winding side. The voltage, in other words, the speed # control signal, is stored in advance in the storage means.

Which stored data is used is determined by the tape speed signal related to the tape winding diameter obtained from the tape speed detection means. Specifically, at which value of the tape speed signal, it is known in advance which speed control signal at which address should be referenced to obtain a constant tape speed, so the speed control signal corresponding to this tape speed signal is referenced. will be done.

In this way, simply by using the tape speed detection signal, the speed side (2) of the winding remoter is performed, and thereby the tape speed is always kept constant regardless of changes in the tape winding diameter.

[Embodiment] Next, an example of the tape speed control circuit according to the present invention will be described.
The speed side of the above-mentioned data recorder (when applied to a wholesale system) will be explained in detail with reference to FIG. 1 and subsequent figures.

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

Then, in the tape speed control circuit 10 of FIG.
is the drive motor on the tape supply side (supply side motor),
IT is a winding side motor. These drive motors IS,
Any IT can use a small motor that produces the amount of torque required in a conventional audio tape recorder.

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

The purpose of constant tension is to stabilize the touch of the tape to the magnetic head from the beginning to the end of tape winding, and to reduce the occurrence of dropouts during data recording and reproduction.

The constant speed control system 10A will be explained first.

Tape speed detection means 2 are provided to detect the tape speed in connection with the take-up motor IT. In this example, a frequency generator (FG) is used as the tape speed detection means 2.
) is used.

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

As a result, the detection element 2B detects the winding side motor I.
The rotational speed of T, and therefore the tape speed of the tape being wound onto the take-up reel side, is detected.

This tape speed detection signal is passed through the frequency divider 3 to 1/m (m
is an integer), and a counter 4 counts the frequency-divided pulses within a unit time.

Therefore, a count output corresponding to the tape speed can be obtained from this counter 4. Since there is a proportional relationship between the tape speed and the amount of tape wound, the extent to which the tape has been wound can be determined by looking at the count output.

The count output is supplied to tape speed control+signal storage means 5. Here, it is known in advance at what tape speed and how much drive voltage should be applied to the take-up motor IT to maintain the tape speed at a constant speed. The storage means 5 stores data necessary to keep the tape speed constant, that is, speed control information at each point from the start of tape winding to the end of tape winding, which should be applied to the winding motor IT.

The relationship between the amount of tape wound and the drive voltage required for the winding motor IT at that time is as shown by the curve L1 in FIG. 3. Therefore, the values of each drive voltage from the start of winding to the end of winding are data (digital data) for speed control signals.
The tape speed detection signal is used to store the data as a tape speed detection signal. For this reason, the storage means 5 may have a ROM configuration and be tabulated.

The speed control I flaw signal referenced 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 an analogized speed control signal is supplied to a child terminal of the operational amplifier 13 via a resistive voltage divider circuit 12 .

The output of the operational amplifier 13 is applied to the winding motor IT via complementary connected output transistors Ql and Q2.

Note that 14 is a feedback resistor.

In this embodiment, in order to eliminate speed fluctuations caused by load fluctuations, the tape speed detection signal is roughly supplied to the frequency/voltage conversion circuit 15, and the tape speed is converted into a predetermined voltage signal. This is supplied to one terminal side of the operational amplifier 13 via a resistor 16.

As a result, the speed of the take-up motor IT is controlled so that the tape speed is constant, taking into account load fluctuations.

Next, the constant tension system 10B will be explained.

The tape speed detection signal is supplied to the monomulti 21 and pulse-shaped so that the pulse width remains constant regardless of speed fluctuations.

The tape speed detection signal whose pulse width has become constant is supplied to an integrating circuit 22 composed of an operational amplifier 23, and an integrated output as shown by straight line L2 in FIG. 4 is formed.

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

The integrated output is supplied to the drive voltage control circuit 25.

This control circuit 25 has an operational amplifier 26, and an integral output is supplied to its child terminal via a level adjustment element 27.

A constant voltage Vo is applied to this child terminal via the level adjustment element 28.
is applied, the output of the operational amplifier 26 obtains a driving voltage (straight line L3) whose output level decreases toward the end of winding, as shown in FIG.

This driving voltage is applied to the operational amplifier 3 that constitutes the constant current circuit 30.
1, and this is roughly supplied to the control transistor Q3, where it is converted into a current. The supply motor IS is connected in series to the current line of this control transistor Q3.

The tape tension is stronger at the end of tape winding than at the beginning, so if the motor split section characteristics are selected as shown in Figure 5, the drive current to the supply motor IS will decrease toward the end of tape winding. Therefore, by such control, it is possible to achieve constant tension and densification.

[Effects of the Invention] As described above, according to the configuration of the present invention, the speed of the take-up motor is controlled based on the tape speed detection signal, so that the tape speed can always be maintained constant.

In that case, in this invention, a speed control signal that can be made constant is stored in advance, and that data is referenced by the tape speed detection signal, so if the data for the speed control signal is increased, the control can be The near-term accuracy is improved, and as a result, high-precision constant speed control can be achieved.

Furthermore, even when controlling the speed, there is no need to record a reference signal on the tape as in the prior art, and there is no need to add a dedicated magnetic head for reproducing the G4.

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

Therefore, the tape speed control circuit according to the present invention is extremely suitable for application to the above-mentioned cassette type digital data recorder.

[Brief explanation of the drawing]

FIG. 1 is a system diagram showing an example of a case where the 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.
The figure is a characteristic diagram for explaining its 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 IT... Winding side motor IS... Supply side motor 2...Tape speed detection means

Claims (2)

[Claims] (1) A tape speed detection means provided in connection with a motor for driving a take-up reel, and a speed control signal storage means in which a speed control signal for the drive motor is stored; A speed control signal stored in the storage means is referenced by the tape speed signal related to the obtained tape winding diameter, and this referenced speed control signal is fed back to the drive motor to adjust the tape winding diameter to a change. A tape speed control circuit characterized in that the drive motor is controlled so that the tape speed is always constant regardless of the speed. (2) As the storage means, a ROM is used in which a speed control signal for controlling the tape speed according to the tape winding diameter on the take-up reel side is stored. Tape speed control circuit as described in Section.