JPH03113768A - Fast forward/rewinding device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to winding of a magnetic tape device such as a VTR (video tape recorder), and fast forwarding/winding that allows the tape to run at high speed in fast forward mode. This relates to a return device.

[Conventional technology]

FIG. 2 is a system diagram showing a tape running device widely used in conventional VH3 type VTR devices. Second
In the figure, 1 is a magnetic tape, 2 is a cylinder, and 3 is a control head. 4 is a capstan motor, the flywheel portion of which is linked by a belt 15 to a gear-type reel disk 14 that rotates a take-up reel or a supply reel. 5 is a supply side light emitting element, 6 is a winding side light emitting element, and 7 is a light receiving element. 8 is a supply side reel, 9 is a take-up side reel, and 10 is a tape cassette.

11 is a mechanical control microcomputer that issues mechanical operation commands; 12 is a capstan motor drive amplifier that drives the capstan motor 4; and 13 is a switch that outputs fast forward/rewind commands to the mechanical control microcomputer 11.

Next, the operation will be explained.

The fast forward operation will be explained. When a fast forward command is issued from the fast forward/rewind command switch 13, the mechanical control microcomputer 11 outputs a drive command for the capstan motor 4 to the capstan motor drive amplifier 12. When the capstan motor 4 rotates, the rotation of its flywheel portion is transmitted to the reel disk 14 via the belt 15, and the take-up reel 9 rotates. When the transparent leader tape at the end of the magnetic tape is reached, the light from the light emitting element 5 passes through, and the phototransistor 7 is turned on to detect the end of the tape. The mechanical control microcomputer 11 receives the signal from the phototransistor 7 which detects the end of the tape and issues a stop signal for the capstan motor 4 to the capstan motor drive amplifier 12. The capstan motor drive amplifier 12 stops the capstan motor 4 upon receiving the stop signal. The flywheel portion of the capstan motor 4 is linked by a belt 15 to a gear-type reel disk 14 that rotates the take-up reel or the supply reel.
When the capstan motor 4 stops, the take-up reel 9 also stops.

The rewinding operation will be explained. When a fast forward command is issued from the fast forward/rewind command switch 3, the mechanical control microcomputer 11 outputs a drive command for the capstan motor 4 to the capstan motor drive amplifier 12. When the capstan motor 4 rotates, the rotation of its flywheel portion is transmitted to the reel disk 14 via the belt 15, and the supply reel 9 rotates. When the transparent glue tape at the beginning of winding of the magnetic tape is reached, the light from the light emitting element 6 passes through, and the phototransistor 7 is turned "ON" to detect the end of the tape. The detected signal is input to the microcomputer 11 in the same way as for fast forwarding, a motor stop command is issued to the capstan motor drive amplifier 12, and the capstan motor 4 is stopped.

When the capstan motor 4 stops, the supply reel also stops, similar to fast forwarding.

By the way, the hub diameter of the reel varies depending on the tape length; the shorter the tape length, the larger the hub diameter; the longer the tape length, the smaller the hub diameter. At the end of rapid feed, the supply reel diameter is almost equal to the hub diameter. Most of the magnetic tape is wound on the take-up reel. When the hub diameters of the supply reel and the take-up reel are the same, if the tape length is long, the overall diameter will be significantly different between the state where the tape is completely wound and the state where the tape is not wound at all. If the hub diameter is small, the load on the take-up reel stand increases as the tape is wound up.

Therefore, the phototransistor is “ON” at the end of the tape.
The fast forward and rewind speeds are adjusted so that even if the capstan motor is stopped, it will not rotate due to inertia and wind the leader tape.

[Problem to be solved by the invention]

The conventional fast forwarding/rewinding device is constructed as described above, and the speed of fast forwarding and rewinding of nine fast forwardings is set to prevent the leader tape from being pulled out too much due to inertia. This invention, which had the problem of taking a long time, was made to solve the above problem. The purpose is to obtain a return device.

[Means to solve the problem]

The fast forward/rewind device according to the present invention is capable of fast forwarding.

During rewinding, the leading edge of the control signal on the tape is detected, the cycle of the control signal is converted into a voltage, and the servo gain is automatically controlled using the voltage to control the rotation of the capstan motor.

[Effect]

In this invention, since the tape speed during fast forwarding and rewinding is controlled to be constant by the control signal detected by the control head, the tape can be run at high speed from the beginning to the end of the tape.

〔Example〕

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

FIG. 1 is a block diagram of a VTR using a fast forward/rewind device according to an embodiment of the present invention, and the same reference numerals as in FIG. 2 are used.
Or a considerable portion. 16 is the control head 3
17 is a servo IC that controls the capstan servo during normal playback and special playback, and 1B is a servo control that performs servo control based on the signal from the servo IC 17. It is a system. 19 is a circuit block that detects the leading edge of the control signal and converts the period to voltage.

Further, FIG. 3 is a waveform diagram for explaining the operation of this embodiment.

Next, the operation will be explained.

When a command is issued by the fast forward/rewind command switch 13, the signal is sent to a mechanical control microcomputer.
The receiver 11 outputs a signal to the capstan motor drive amplifier 12 to rotate the capstan motor 4, and the capstan motor drive amplifier 12 rotates the capstan motor 4. The flywheel portion of the capstan motor is linked by a belt 15 to a gear-type reel disk 14 that rotates the supply reel 82 and the take-up reel, so that the take-up and supply reels rotate in accordance with the rotation of the capstan motor 4, thereby producing tape. 1 runs. Here, the control signal written on the magnetic tape is picked up by the control radar 3, and the control signal is picked up by the amplifier 16.
The signal is amplified and input to the servo IC 17, and this is formed into a square wave by the Schmitt amplifier of the servo IC 17.

FIG. 3(a) shows the shaped control signal.

The signal is transmitted through capacitor C2 and resistor R8 as shown in Fig. 3(b).
), and further diode DI, resistance Re,
Figure 3 (C) with capacitor C3 and resistor R1°
Peak detection is performed as shown below. The period of the control signal shown in FIG. 3(a) becomes shorter as the tape travels faster. If the period becomes shorter, the peak detected DC voltage in FIG. 3(C) will increase, turning the transistor Tr ON and restricting the input voltage input to the capstan motor drive amplifier 12 by R11. Meanwhile, fast forward.

When rewinding, the SW is activated by the signal from the command switch 13.
l is turned on, and the motor drive voltage is controlled so that the tape running speed does not rise above a certain level.
The tape runs at a constant speed over its entire length. Note that the servo system 18 normally uses a PWM (Puts Wide Modulator) for speed control from the servo IC 17.
r) and a PWM for phase shift control, which inputs the DC-added voltage to an operational amplifier through a filter consisting of a resistor R1 and a capacitor CI, and supplies the output of the operational amplifier as a voltage for driving the motor. The stopping means at the transparent leader tape portion at the end of the tape during fast forwarding and rewinding is exactly the same as the conventional one.

As described above, in this embodiment, since the tape speed during fast forward and rewind is controlled at a constant speed using the control signal detected by the control head, it is possible to perform two fast forward and rewinds at a constant speed over the entire tape. This suppresses the phenomenon in which the running speed increases as the end of the tape approaches, and prevents damage to the tape due to the leader tape being pulled out due to the inertia of high-speed rotation.

〔Effect of the invention〕

As described above, according to the present invention, peak detection is performed on the control signal during fast forwarding and rewinding, and feedback is applied.
Since the entire tape is run at a constant speed, the speed during high-speed fast forwarding and rewinding is constant, and there is an effect that stable high-speed fast forwarding and rewinding can be performed without damage even at the end portion of the tape.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a VTR tape running device and control system using a fast forward/rewind device according to an embodiment of the present invention, FIG. 2 is a diagram showing a conventional fast forward/rewind device system, and FIG. 3 is a diagram showing a conventional fast forward/rewind device system. The figure is a waveform diagram for explaining the operation of this embodiment. 1 is a video tape, 3 is a control head, 4 is a capstan motor, 8 is a supply reel, 9 is a take-up reel, 13 is a fast forward/rewind command switch, 18 is a normal servo system, and I9 is a control signal feedback system. . Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] (1) A reel drive means that rotates the take-up reel during fast forwarding and rotates the supply reel during rewinding, a control head that picks up control signals on the tape, and a voltage that determines the period of the control signal detected by the control head. A fast forwarding/rewinding device comprising: a control means for converting the voltage and feeding back the voltage to the reel driving means to control the tape running speed during fast forwarding and rewinding to be constant.