JPH02195557A - Tape drive controller - Google Patents

Abstract

PURPOSE:To control the driving speed of a reel drive disk at a fixed level regardless of the mechanical load caused between a take-up reel and a supply reel, the tape load, etc., by controlling the reel motor of the supply side via a servo means in order to secure the coincidence between a reference signal and the output signal of a detecting means. CONSTITUTION:A switch circuit 6 instructs the tape driving direction with a tape driving direction command signal and connects a drive circuit 3 to a take-up reel motor 1 and then connects a detecting circuit 4 and a servo circuit 5 to a supply reel motor 2 respectively. The circuit 4 detects the counter induced voltage produced with revolution of the motor 2. Then the servo circuit 5 control the drive of the motor 2 so as to secure the coincidence between the detecting result of the circuit 4 and the voltage set at a fixed prescribed level as a reference signal received from a reference signal production means 7. As a result, the driving speed of a reel drive disk at a fixed level regardless of the influence of a tape path produced between the take-up and supply reels.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a tape drive control device for a tape recorder.

[Conventional technology]

For example 1. In digital audio tape recorders (hereinafter referred to as DAT) and video tape recorders (hereinafter referred to as VTR) that record and play back audio signals using PCM, FF (fast forward), REW (rewind), or the so-called When performing high-speed tape running such as high-speed search or picture search (high-speed playback), it is necessary to easily adjust the tape tension or child speed in order to prevent uneven tape winding or tape damage and to ensure high-speed searches. Moreover, it is necessary to control it reliably.

As a prior art of this type, there is a tape drive control device for a tape recorder as disclosed in Japanese Patent Laid-Open No. 56-44141.

A conventional tape drive control device for a tape recorder will be described below.

FIG. 8 shows a conventional tape drive control device for a tape recorder. In FIG. 8, 81 and 82 are reel motors (DC motors) on the take-up side and supply side, respectively.

A speed control signal is supplied from an input terminal 83 to the reel motor 81 on the winding side via a drive circuit 84 . The speed control signal supplied to the reel motor 81 may be of any type as long as it can keep the rotational torque of the reel motor 81 constant, and in this conventional example, when the reel motor 81 is driven at a constant voltage, shows.

On the other hand, during winding, the reel motor 82 on the supply side is reversely rotated by the reel motor 81 on the winding side via a tape (not shown), and the bank tension in the forward rotation direction is applied against this rotation. Is the tension system better than the drive circuit 85 to get it? It is a conventional method to provide an i signal.

In this conventional example, a detection means for detecting the drive current of the reel motor 81 on the winding side, for example, a resistor 86 is provided, and the voltage generated across the resistor 86 is compared via a differential amplifier 87. It is supplied to one input end of 2S88. The voltage comparator 88 then compares a predetermined reference voltage supplied from the other input terminal 89 with the detection voltage supplied via the differential amplifier 87, and determines the difference between the two. The drive circuit 8 controls the bank tension by the reel motor 82 on the supply side according to the magnitude of the voltage.
5, and the rotational torque of the reel motor 81 on the take-up side, which is engaged with this reel motor 82 via the tape, is configured to be constant.

In such a configuration, as a result of the torque generated in the motor overwhelming the drive current of the motor, when the drive current of the reel motor 81 changes due to load fluctuations in the tape path system, the drive current of the reel motor 81 is detected. The terminal voltage of resistor 86 changes.

The changed terminal voltage of the resistor 86 is then supplied as a detection voltage to a voltage comparator 88 via a differential amplifier 87 and compared with a reference voltage. The voltage comparator 88 is set in advance so that when the detected voltage is higher than the reference voltage, the level of its output becomes smaller, and vice versa.

Therefore, if the drive current of the reel motor 81 increases due to load fluctuations, its rotational torque also increases (but
At this time, the output level of the voltage comparator 88 becomes small as described above, so the torque in the forward rotation direction of the reel motor 82 which is energized via the drive circuit 85 in accordance with the output level of the voltage comparator 88, i.e. Back tension is also reduced. As a result, the torque of the reel motor 82 that is engaged with the reel motor 81 via the tape becomes smaller, and the drive current of the reel motor 82 also becomes smaller. Therefore, a constant rotational torque is maintained, a constant speed of the reel stand on the winding side is obtained, and the tape speed can be kept constant.

Furthermore, when controlling the tape tension, the above-mentioned detected voltage is weighted by using the tape winding diameter as a control coefficient. In other words, since the torque of the reel motor is proportional to the product of the tape tension and the winding diameter, the torque of the reel motor 81 on the winding side is kept constant, and the ζ tape tension is adjusted according to changes in the tape winding diameter. Control. For that,
Frequency generators (not shown) are arranged in each of the reel motors 81 and 82 to extract pulse signals corresponding to the winding diameter of the tape, compare the phases, and convert the comparison difference signal to the detection voltage detected by the resistor 86 or It is added to the output of voltage comparator 88.

By weighting the signals related to the tape winding diameter, the back tension of the reel motor 82 is adjusted in the same manner as described above, making it possible to accurately control the tape tension.

[Problem to be solved by the invention]

However, in the configuration of the conventional example, the signal for controlling the reel motor 82 on the supply side is based on the signal detected from the drive current of the reel motor 81 on the winding side. This method has the problem that the effects of tape load and tape path are not taken into consideration at all. Furthermore, in order to perform tape tension control, a detection element (frequency generator) for detecting the state of both reel motors 81 and 82 is connected to both reel motors 81 and 82.
1.82 has the problem that it needs to be newly added.

The purpose of this invention is to be able to control tape drive by eliminating the effects of mechanical loads and tape loads that occur between the take-up reel and the supply reel, and to detect the state of both reel motors especially when performing tape tension control. It is an object of the present invention to provide a tape drive control device that does not require the addition of a new detection element for detecting the detection element.

[Means to solve the problem]

The tape drive control device according to claim (1) includes a detection means for detecting a reverse induced voltage generated by rotation of a supply side reel motor of a pair of reel motors, and a servo for driving and controlling the supply side reel motor. means, a switching means for switching the connection of the detection means and the servo means to the reel motor on the supply side according to the running direction of the tape, and generating a reference signal having a voltage value at a predetermined constant level as a control reference for the servo means. and a reference signal generating means for generating a reference signal.

Then, the servo means controls the reel motor on the supply side so that the reference signal and the output signal of the detection means match.

The tape drive control device of claim (2) differs from claim (1) in that the reference signal generation means controls the servo means. A reference signal having the following characteristics is generated.

The rest is the same as claim (1).

[For production]

In the tape drive control device according to claim 1), the detection means detects the reverse induced voltage generated by rotation of the reel motor on the supply side. The detection result by this detection means and the reference signal outputted by the reference signal generation means, Claim (1)
In this case, the servo means drives and controls the reel motor on the supply side so that the voltage value matches a predetermined constant level, so that the winding measurement is influenced by the tape pass between the reel and the supply reel. This enables constant speed control of the reel stand.

In the tape drive control device according to the second aspect, since the reference signal has a voltage value corresponding to the diameter of the tape wound on the supply reel, constant control of the tape tension is possible.

〔Example〕

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

FIG. 1 shows a block diagram of a tape drive control device in a first embodiment (corresponding to claim fl) of the present invention. In FIG. 1, reference numeral 1 denotes a reel motor, which in the illustrated state is on the winding side. 2 is a reel motor, which is on the supply side in the illustrated state. 3 is a drive circuit that drives the reel motor 1 on the winding side in accordance with the torque command voltage (speed command voltage), and 4 is the reel motor 2 on the supply side.
5 is a detection circuit that detects a reverse induced voltage generated by the rotation of the reel motor 2, and 5 is a servo circuit that drives and controls the reel motor 2 on the supply side.

6, in accordance with the tape running direction command signal, drives the drive circuit 3 to the reel motor 1.2 in accordance with the direction in which the tape should be run.
of the reel motor (in the case shown, the reel motor l
A switching circuit that connects the detection circuit 4 and the servo circuit 5 to the supply side of the reel motors 1 and 2 (reel motor 2 in the illustrated case). be.

Reference numeral 7 denotes a reference signal generation circuit that generates a reference signal that serves as a control reference for the servo circuit 5. The reference signal in this case has a voltage value at a predetermined constant level.

Next, the operation of the tape drive control device of this first embodiment will be described. In this embodiment, reel motors 1 and 2
Let be a DC motor. Further, the drive circuit 3 causes the reel motor l on the winding side to generate a torque proportional to the input torque command voltage, and here, the reel motor l on the winding side is driven by current.

When the tape is run in one direction (reel motor 1 is on the take-up side and reel motor 2 is on the supply side)
will be explained using an example. By commanding the tape running direction with the tape running direction command signal, the switching circuit 6 connects the drive circuit 3 to the reel motor l on the winding side,
The detection circuit 4 and the servo circuit 5 are connected to the reel motor 2 on the supply side.

When a predetermined torque command voltage is input to the drive circuit 3, the drive circuit 3 current-drives the reel motor l on the winding side with a voltage proportional to the input torque command voltage.

By the way, the torque generated in a DC motor is proportional to the current flowing through the DC motor. That is, if the generated torque is T, the current flowing through the DC motor is I, and the torque constant of the DC motor is KT, then the following equation holds true.

T=ni,,・I ・・・・・・(
1) Therefore, the reel motor 1 on the winding side rotates with constant torque when the current is constant. This causes the tape to run in one direction. Therefore, as the tape runs, the reel motor 2 on the supply side is forced to rotate in the same rotational direction as the reel motor 1 on the winding side. The reel motor 2 on the supply side generates a reverse induced voltage by rotating.

FIG. 2 shows an equivalent circuit diagram of a reel motor (DC motor), which will be described below with reference to FIG.

If the voltage applied to the DC motor is E8, the coil resistance of the DC motor is Ra, the current flowing through the DC motor is l, and the reverse induced voltage generated in the DC motor is Ea, then from the equalization circuit shown in Figure 2, the following equation is obtained. To establish.

Es-Ea +Ra ・I −・−・・
(21 Therefore, from equations (1) and (2),
The torque T generated in the reel motor 2 on the supply side is expressed by the following formula.

Ka Further, when the power generation coefficient of the reel motor 2 is Ka and the rotation speed is N, the following equation holds true.

Ea = Ka −N ・Self・−・
(41 That is, the reverse induced voltage Ea generated in the reel motor 2 is proportional to the rotation speed N of the reel motor 2.

As can be seen from equation (4), the reel motor 2 on the supply side
The rotation speed N of the reel motor 2 on the supply side can be determined from the reverse induced voltage Ea. Therefore, by controlling the reverse induced voltage Ea generated in the reel motor 2 on the supply side to be constant by the servo circuit 5, it is possible to control the reel stand at a constant speed.

Therefore, now suppose that the output of the detection circuit 4 is Eas,
Let Nso be the control target value of the rotation speed N of the reel motor 2, and let E aso be the reverse induced voltage corresponding to the control target value Nso.
and the rotational speed of the motor when the reverse induced voltage is Eas is Ns
Then, from equation (4), Easo = Ka 0
Nso ・−・=・(51as N゛ −・・・・・, (6) Ka) Therefore, the difference between the actual rotation speed Ns of the reel motor 2 on the supply side and the control target value Nso, ie Ns-Ns
o, that is, by setting Eas-Easo to zero, the number of rotations of the reel motor 20 on the supply side can be kept constant.

Therefore, the reference signal generation circuit 7 only needs to generate the base i/v signal (in this case, a voltage having the value of E aso) and output it to the servo circuit 5.

Here, the detection circuit 4 and reference signal generation circuit 7 in the first embodiment will be explained in detail.

FIG. 3 fa+ shows a block diagram of the detection circuit 4, and FIG. 3 (bl shows a block diagram of the reference signal generation circuit 7).

The detection circuit 4 is composed of a differential amplifier 41 and a rectifier 42, as shown in FIG. By taking the difference in motor drive voltage and rectifying this difference with a rectifier 42, a reverse induced voltage is obtained as a DC voltage.

Further, the reference signal generation circuit 7 is constituted by a DC power supply 43 having a predetermined voltage value E aso, as shown in FIG. 3 flJ.

Therefore, by driving and controlling the reel motor 2 on the supply side with the servo circuit 5 so that the output difference between the detection circuit 4 and the reference signal generation circuit 7 having the above-described configuration becomes zero, constant speed control of the reel stand can be performed. It becomes possible.

Next, the operation of the servo circuit 5 will be explained.

FIG. 4 is a block diagram showing a specific configuration of the servo circuit 5 of FIG. 1. This servo circuit 5 is composed of a voltage comparator 2331 and a current amplifier 32.

First, in the voltage comparison 2331, the voltage comparator 31 compares the reverse induced voltage of the supply side reel motor 2 detected by the detection circuit 4 and the reference signal input to the servo circuit 3. This voltage comparator 31 is configured to reduce the current flowing to the supply reel motor 2 when the reference signal is larger than the reverse induced voltage. When the former and the latter are equal, the current is not passed through the reel motor 2, and when the former is smaller than the latter, the current flowing through the reel motor 2 is increased so as to generate torque in the same rotational direction as the motor l. In other words, torque command voltages are applied to the current amplifiers 32 so that the reel motor 2 on the supply side generates torque in the forward rotation direction (in the reverse rotation direction with respect to the reel motor 1 on the winding side). As a result, the current amplifier 32 is connected to the voltage comparator 31
The reel motor 2 is current-driven in accordance with the torque command voltage which is the output of the reel motor 2.

As described above, the servo circuit 5 drives the reel motor 2 on the supply side so that the difference between the output signal of the detection circuit 4 input to the servo circuit 5 and the reference signal of the reference signal generation circuit 7 becomes zero. When controlled, constant speed control of the reel stand becomes possible.

In this embodiment, constant speed control of the reel stand is performed by detecting the reverse induced voltage of the reel motor 2 on the supply side and controlling the reel motor 2 on the supply side. Tape drive can be controlled without the influence of mechanical loads and tape loads that occur between the side reels.

FIG. 5 is a block diagram showing the configuration of a tape drive control device according to a second embodiment of the present invention, and FIG. 6 shows a specific configuration of a detection circuit 8 and a reference signal generation circuit 9 in this second embodiment. 7 is a block diagram, and FIG. 7 is an explanatory diagram of the operation of FIG. 6.

The second embodiment will be described below with reference to these drawings.

The embodiment of FIG. 5 is different from the embodiment of FIG.
and the reference signal generation circuit 9 are different, and the rest is the same as that of FIG. 1.

Now, if the tape tension between the take-up reel and the supply reel is F, and the winding radius of the tape wound on the take-up reel and the supply reel is ``3.''2, then the take-up side The torque T generated in the reel motor 1 and the reel motor 2 on the supply side, respectively.
1 and T2 are as shown in the following equation.

Tl=F-r1-...
・・・+71T2-F・``2...Auto・(8) By the way, equations (7) and (8) are based on the effect of mechanical load, tape load, etc. between the take-up reel and the supply reel. It holds true if there is no such thing, but in reality, it is
There is a difference between the tape tension seen from the take-up reel and the tape tension seen from the supply reel. If the torque generated by the tape tension difference between the take-up reel and the supply reel is T, then equation (3) and (
8) From Equation 2 and Equation (9), the following equation holds true.

F □ T = □ + 2 r2 2Ra Here, since the reel motor 1 on the winding side is driven with a constant current, the torque T1 is always constant. Also, T=
If the reverse induced voltage generated in the supply side reel motor 2 at the time of O is Eao, the following equation holds true.

r2 2Ra...Ol Therefore, the following equation holds true from equation (9) and equation 001.

r2 r2 Ra . . . 00 Therefore, according to equation 00, the change in tape tension between the take-up reel and the supply reel can be detected by the reverse induced voltage generated in the reel motor 2 on the supply side. That is, by controlling the supply reel motor 2 with the servo circuit 5 so that the right side of equation 00 becomes zero, the tape tension between the take-up reel and the supply reel can be made constant.

Next, a specific method for setting the right side of equation 00 to zero will be described. As can be seen from formula 00, voltage Ea and voltage E
The servo circuit 5 controls so that the ao and the ao match. That is, the voltage Ea is the output of the detection circuit 8, and the voltage Eao is input to the servo circuit 5 as a signal of the reference signal generation circuit 9.

Incidentally, the reverse induced voltage generated in the reel motor 2 on the supply side is inversely proportional to the winding diameter of the tape wound on the reel. Therefore, when the tape wound on the supply reel is pulled with a constant torque, the reel motor 2 on the supply side
The above-mentioned control becomes possible by generating the reverse induced voltage generated in the reference signal as a reference signal. The configuration and operation of the reference signal generation circuit 9 and detection circuit 8 that generate this reference signal will be described below.

FIG. 6 shows a block diagram of the detection circuit 8 and the reference signal generation circuit 9. In FIG. 6, the detection circuit 8 is composed of a differential amplifier 61, a rectifier 62, and a voltage comparator 63. Its operation is as follows. That is, the differential amplifier 51 calculates the difference between the voltage generated in the motor coil of the reel motor 2 and the motor drive voltage, and this difference is applied to the rectifier 6.
2, the reverse induced voltage is obtained as a DC voltage.

Furthermore, by comparing the output of the differential amplifier 61 and the output of the rectifier 62 with the voltage comparator 63, the reel motor 2 is
Generates a detection signal that detects rotation.

The above operation will be explained in detail based on the operation explanatory diagram of FIG. In other words, the voltage generated in the motor coil is as shown in Figure 7 (
As shown in tb+ in FIG. 7, it is a combination of the reverse induced voltage E1 and the motor drive voltage E2, and the waveform obtained by removing the motor drive voltage E2 from this is the waveform shown in tb+ in FIG. be.

This is the reverse induced voltage E1 generated in the reel motor 2, and is a sine wave. One period T1 of this sine wave corresponds to one rotation of the reel motor 2, and its amplitude is proportional to the torque of the reel motor 2.

Next, by rectifying the output signal of this differential amplifier 61 with a rectifier 62, a DC voltage Ea proportional to the reverse induced voltage is obtained. This is shown in Figure 7 tc+.

Next, the voltage comparator 63 compares the signal 711fbl with the signal tc+ in FIG. 7 to obtain the waveform shown in fdl in FIG. In this waveform, one pulse appears for each cycle of the sine wave shown in FIG. 7 fbl. In other words, the voltage comparator 63 outputs one pulse for each rotation of the reel motor 2.

Further, in FIG. 6, the reference signal generation circuit 9 includes a counter 64, a read-only memory (hereinafter abbreviated as ROM) 65, a D/A converter 66, and an A/D converter i! 1i67 and a differential amplifier 68. Its operation is as follows.

That is, the counter 64 counts the number of rotations of the reel motor 2 by counting the output pulses of the voltage comparator 63. The operation mode of the counter 64 is a reversible counter that changes into an up counter and a down counter in accordance with the tape running direction command signal. moreover,
Data for generating a reference signal corresponding to the winding diameter of the supply reel is written in the ROM 65.

Therefore, by using the output of the counter 64 as the read address of the ROM 65, the ROM 65 outputs data corresponding to the winding diameter of the reel. This output data is converted into an analog signal by a D/A converter 66 and output as a reference signal.

Furthermore, it is necessary to output a correct reference signal even if the above-described operation is performed from any tape winding diameter state.

This will be explained below. First, the difference between the outputs of the base jg signal rectifier 62 is determined by the differential amplifier 68. The output of this differential amplifier 68 is converted into a digital signal by an A/1 converter 67 (applied to a negative counter 64.
4 calculates the sum of the digital signal manually inputted from the A/D converter 67 and the counter value immediately before this digital signal is manually inputted, and sets this as the initial value of the counter 64.

With the above operations, it becomes possible to specify the diameter of the tape on the reel.

As described above, with the above-described configuration, it is possible to keep the tape tension between the take-up reel and the supply reel constant in any tape winding state and in any tape running mode (recording/playback or high speed). Moreover, as in the first embodiment, tape drive can be controlled without the influence of mechanical loads and tape loads occurring between the take-up reel and the supply reel. Further, for constant tape tension control, it is not necessary to provide a special detection element on both lumokes 12, and the configuration is simple and inexpensive.

〔Effect of the invention〕

According to the tape drive control device of claim (1), the detecting means detects the reverse induced voltage generated by the rotation of the supply-side glue motor of the pair of reel motors, and also drives the supply-side reel motor. The servo means generates a predetermined constant voltage value in a reference signal generation circuit as a reference signal serving as a control reference for the servo means to be controlled, so that the output signal of the detection means and the reference signal of the reference signal generation means match. Since we controlled the drive of the reel motor on the supply side,
Constant speed control of the reel stand can be performed without being affected by mechanical loads, tape loads, etc. between the take-up reel and the supply reel.

Further, according to the tape drive control device of claim (2), the reference signal generation circuit generates a value M according to the winding diameter of the supply reel.
ii! Since it is generated as a signal, the tape tension between the take-up reel and the supply reel can be kept constant without being affected by mechanical load or tape load between the take-up reel and the supply reel. .

Furthermore, in claim (2), since the reverse induced voltage generated in the reel motor is used to detect changes in the rotational speed of the reel motor and changes in tape tension, no special detection element is required at all, and the configuration is simple. It is cheap.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing the configuration of a tape drive control device according to a first embodiment of the present invention, Fig. 2 is an equalization circuit diagram of a reel motor, and Fig. 3 is a detection circuit in the first embodiment. FIG. 4 is a block diagram showing the specific configuration of the servo circuit 5 in FIG. 1, and FIG. 5 is a block diagram showing the f71 configuration of the reference signal generation circuit. FIG. FIG. 6 is a block diagram showing the specific configuration of the detection circuit and reference signal generation circuit in the second embodiment. FIG. 7 is an explanation of the operation of the detection circuit and reference signal generation circuit in FIG. 6. FIG. 8 is a block diagram showing the configuration of a conventional tape recorder drive control device. l... Reel motor on the winding side, 2... Reel motor on the supply side, 3... Drive circuit, 4.8... Detection circuit, 5... Servo circuit, 6... Switching circuit , 7.9・
...Reference signal generation circuit diagram (a)! E2 F-m- (c) Fig.

Claims (2)

[Claims] (1) A detection means for detecting the reverse induced voltage generated by the rotation of the supply side reel motor of the pair of reel motors, a servo means for driving and controlling the supply side reel motor, switching means for switching the connection of the detection means and the servo means to the reel motor on the supply side in accordance with the above; and reference signal generation means for generating a reference signal having a voltage value at a predetermined constant level as a control reference for the servo means; A tape drive control device comprising: the servo means controlling the reel motor on the supply side so that the reference signal and the output signal of the detection means match. (2) a detection means for detecting the reverse induced voltage generated by the rotation of the supply side reel motor of the pair of reel motors; a servo means for driving and controlling the supply side reel motor; a switching means for connecting and switching the detection means and the servo means to the reel motor on the supply side according to the switching means; and a voltage value corresponding to the winding diameter of the tape wound on the supply reel as a control reference for the servo means. and a reference signal generating means for generating a reference signal having the following characteristics, wherein the servo means controls the reel motor on the supply side so that the reference signal matches the output signal of the detecting means. .