JPS629559Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention is a reel motor that improves the drive torque when changing the direction of fast winding in a tape recorder that uses dedicated motors for the reels on the sending and take-up sides of magnetic tape. Regarding control circuits.

Changing the direction of fast winding in a tape recorder using a dedicated motor for each reel is accomplished by a circuit constructed as shown in FIG. In the figure, 1 is a magnetic tape that is spread across a left reel 2 and a right reel 3. The left reel 2 is driven by a left motor 4, and the right reel 3 is driven by a right motor 5. There is.

During fast forwarding (hereinafter referred to as FF), switches 6 and 7 are switched to the FF side, the output of the left motor drive circuit 8 is cut off, and the output of the right motor drive circuit 9 is sent via the switch 7 to the right motor 5. Then, the motor 5 rotates and the magnetic tape 1 is wound from the left reel 2 to the right reel 3 at high speed.

In this case, the rotation of the right reel 3 is detected as a frequency signal by the right frequency generator 10, converted to a voltage signal by the right F/V converter 11, and added to the right addition point 12 as a negative feedback signal. A reference voltage (higher than the voltage level during normal reproduction or recording due to high-speed feeding) is applied in positive phase to the right addition point 12, and the output of the right addition point 12 is input to the right motor drive circuit 9. Therefore, the rotation speed of the right motor 5 is servo-controlled, and the right motor 5 continues to rotate while maintaining a predetermined high rotation speed.

As a result, as the winding of the magnetic tape 1 onto the right reel 3 progresses and the tape winding diameter of the left reel 2 decreases, the rotation of the left reel 2 gradually decreases because the right reel 3 rotates at a constant speed. As a result, the frequency generated by the left frequency generator 13 becomes higher, the voltage level obtained by conversion by the left F/V converter 14 becomes higher, and the output voltage of the left summing point 15 becomes lower.

Therefore, in the above situation, the fast winding direction is set to FF.
Even if switches 6 and 7 are switched to the REW side in order to change from REW (rewind) to Therefore, the left motor 4 cannot be given sufficient rotational force. For this reason,
The rise of REW, that is, the reversal of tape running becomes delayed.

Therefore, problems arise when locating the beginning of recorded content on a magnetic tape and other operations.

An object of the present invention is to provide a reel motor control circuit that can minimize the time delay when reversing the running direction of a tape during early winding.

The present invention will be explained below with reference to examples. Second
The figure is a circuit diagram showing an embodiment, and the same reference numerals as in FIG. 1 indicate the same parts. In this figure, basically transistors 16 and 17 are connected between the output sides of the left and right F/V converters 14 and 11 and the ground, respectively, and the transistors 16 and 17 are turned on during switching during high-speed rotation. F/V converter 1
Make sure that outputs 4 and 11 escape to ground.

These transistors 16 and 17 are monomulti 18
The mono multi 18 can be turned on for a certain period of time depending on the output of the or gate 19.
is set to be triggered on the rising edge of the output. The outputs of the left and right integrating circuits 20 and 21 are applied to the OR gate 19. Capacitors C ₁ and C ₂ of integrating circuits 20 and 21
is for integration, resistors R ₁ and R ₂ are for discharging the charges of capacitors C ₁ and C ₂ , and diodes D ₁ and D ₂ are for charging. In other words, the charging time constant of the integrating circuits 20 and 21 is considerably larger than the discharging time constant.
Reference numeral 22 denotes a fast winding direction changeover switch for switching the voltage V ₀ of the reference power source 23 to the addition point 12 or 15.

In the above, assuming that the changeover switch 22 is switched to the FF side, the reference voltage V ₀ is added to the right addition point 12, and the right motor 5 continues to rotate at a constant speed under servo control. When this condition progresses and the tape winding diameter of the left reel 2 becomes smaller and its rotational speed increases, the selector switch 22 is switched to REW.
When switched to the side, the following operations occur.

That is, when the changeover switch 22 is switched to the REW side, the reference voltage _V0 is not only applied to the left summing point 15, but also applied to the left integration circuit 20, and the capacitor C is charged by the charging current flowing through the diode _{D1. 1} is immediately charged, and the charging voltage is applied to the monomulti 18 via the OR gate 19. Therefore, an output is output from the monomulti 18 for a predetermined time, transistors 16 and 17 are turned on for the predetermined time, and the outputs of the F/V converters 11 and 14 are made zero.

Therefore, the output of the left summing point 15 has the reference voltage
V ₀ appears as is, so that the maximum voltage is applied from the left motor drive circuit 8 to the left motor 4, and the motor 4 starts rotating with maximum torque,
The left reel 2 is driven in the direction of arrow A.

As a result of the above, when switching from FF to REW,
There is no significant delay in tape winding in the REW direction. FIG. 3 is a timing chart of the above operation, and a to e indicate the level of potential at points with the same symbols in FIG. 2. In addition, in the above, FF→
I explained the REW switching operation, but REW→
The FF switching operation is performed in exactly the same manner.

As described above, according to the present invention, the time delay when switching FF←→REW is shortened, and the intended purpose can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of a conventional reel motor control circuit, FIG. 2 is a circuit diagram of an embodiment of the same circuit according to the present invention, and FIG. 3 is a timing chart of the circuit shown in FIG. 2.

Claims (1)

[Scope of utility model registration request] In a tape recorder in which two reels are driven by separate motors and the rotation of the take-up reel is servo-controlled, an operation signal for switching the running direction of the magnetic tape during early winding is detected. , by switching the running direction, the rotation speed feedback signal from the reel working next as the take-up side is temporarily interrupted by the operation signal, and the servo control of the motor on the reel side working next as the take-up side is performed. A reel motor control circuit characterized in that the reel motor is temporarily released.