KR100209805B1 - Device and method for automatic adjusting of 6.5h in a vcr - Google Patents

Abstract

The present invention relates to a 6.5H automatic adjustment apparatus and method of a VCR for adjusting a difference between a switching pulse provided to a video head of a VCR and a vertical synchronization signal detected from a VCR tape by 6.5H, And detects the difference between the switching pulse and the vertical synchronizing signal whose phase is converted to correspond to the converted resistance value. If the difference is within 381 to 445 μs, the variable resistor And the resistance value conversion is stopped.

Description

V-SEAL 6.5H automatic adjustment device and method

The present invention relates to a 6.5H automatic adjustment apparatus and method in a VCR (Video Cassette Recorder), in particular, for adjusting a recording start point of a recording track recorded on a tape to come before 6.5H of a vertical sync signal.

A VCR selectively magnetizes a video tape as a magnetic body from a head, thereby recording video and audio signals, or reproducing video and audio signals recorded on a video tape.

In order to record / reproduce video and audio signals on a video tape in such a VCR, it is necessary to rotate the head drum in accordance with the field of the video signal. Such a control is generally referred to as a servo control system of the VCR.

That is, the servo control system maintains a proper speed and phase relationship between the rotation of the capstan and the head drum in the recording and reproduction mode, and controls the switching pulse of the head in accordance with the rotation of the head drum, Which can accurately record and reproduce information.

More specifically, the VCR includes a magnetic tape running at a constant speed (33.35 mm / sec in the SP mode, 16.67 mm / sec in the LP mode, and 11.12 mm / sec in the EP mode) So that the relative position of the head and the tape is maintained so that the vertical blanking period is recorded at the lower end of each track.

During playback, you must maintain the same speed as the tape running speed at the time of recording, rotate the video head exactly to 30 Hz, and also ensure that the video head traces correctly over the recorded video tape track.

In order to do this, phase control and speed control are applied to the capstan motor and the drum motor. The phase control system performs control by small fluctuation and the speed control system performs control for large fluctuation.

From these two controls, the capstan motor maintains the specified tape speed, and the drum motor maintains the constant speed by suppressing the rotation fluctuation at the time of the hatching change or the start.

As described above, in the VCR, two video heads are arranged at 180 ° positions on a drum which rotates 30 times per second, and recording and reproducing are performed with the video head. The tape is wound around the rotary drum at an angle of about 180 °. Therefore, one field is continuously recorded as an inclined track on the tape. In order to sequentially record an image of one field on each head, it is necessary to rotate the rotary head one rotation every 1/30 second. Therefore, it is necessary to perform speed control to control the rotation speed. It also specifies that the recording start point recorded on the tape comes before 6.5H of the vertical sync signal. This is to make the switching timing of the head before 6.5H of the vertical synchronizing signal so that the joint part of the image is positioned at the bottom of the screen. Therefore, the head position of the rotary drum needs to be adjusted to a constant timing with the vertical synchronizing signal.

This will be described with reference to FIGS. 1 and 2.

In FIG. 1, the drum 10 makes one revolution per 1/30 second. The two video heads 20 and 30 attached to the drum 10 are spaced apart from each other by 180 degrees and the tape 40 is wound around the rotary drum 10 by about 180 degrees.

At this time, in order to set the timing so that the recording start point recorded on the tape 40 comes before 6.5H of the vertical synchronizing signal as in the second aspect, the PG sensor 50 controls the rotation speed of the drum 10 The video head 20 should be positioned about 20 degrees from the point where the contact between the drum 10 and the tape 40 is started at the point of time when the PG (Pulse Generator) pulse generated one by one is generated.

That is, when the drum 10 rotates by about 20 degrees from the time when the PG pulse (see FIG. 2a) is generated, the tape 40 and the video head 20 are brought into contact with each other. At this time, 2b) is supplied. As the drum 10 rotates about 20 占 after the PG pulse (see Fig. 2a) is generated in this manner, when the tape 40 and the video head 20 are brought into contact with each other, A difference of 6.5H occurs between the recording start point Z1 on the tape 40 and the vertical synchronizing signal (second c) on the tape 40) position Z2 as shown in Fig.

At this time, it is difficult to accurately position the video head 20 at about 20 ° from the point where the contact between the drum 10 and the tape 40 is started at the point of time when the PG pulse is detected due to the mechanical assembly error as shown in FIG. . Therefore, conventionally, by adjusting the resistance value of the variable resistor provided inside the VCR, the width between the switching pulse and the vertical synchronization signal is finely adjusted to perform 6.5H adjustment. However, in the conventional 6.5H adjustment, the adjustment of the resistance value of the variable resistor was performed manually by a person to adjust the 6.5H adjustment.

Accordingly, it is an object of the present invention to provide a 6.5H automatic adjustment apparatus and method capable of automatically performing 6.5H adjustment of a VCR.

In order to achieve the above object, there is provided a 6.5H automatic adjusting apparatus for a VCR, which adjusts a difference between a switching pulse provided to a video head of a VCR and a vertical synchronizing signal detected from a VCR tape by 6.5H, A vertical synchronization signal detector for detecting a synchronization signal; A switching pulse detector for detecting a switching pulse provided to the video head; A variable resistor for finely adjusting the phase of the switching pulse so as to correspond to a resistance value; A voltage detector for detecting a voltage value across the variable resistor; A motor for adjusting a resistance value of the variable resistor; A motor driving unit for driving the motor; And a control unit for providing the motor driving unit with a driving control signal for adjusting the resistance value of the variable resistor so that the interval between the switching pulse and the vertical synchronizing signal is 6.5H. A method for adjusting a 6.5H automatic adjustment method using a device for adjusting a difference between a switching pulse of a video head whose phase changes according to a resistance value and a vertical synchronization signal detected from a VCR tape by 6.5H, Transforming the resistance value of the variable resistor so that the resistance value becomes? Detecting a difference between a switching pulse and a vertical synchronizing signal whose phase is converted to correspond to the converted resistance while converting a resistance value of the variable resistance by a predetermined ohm (?); And stopping the resistance value conversion of the variable resistor when the difference between the phase-converted switching pulse and the vertical synchronization signal is within 381 to 445 μs.

Figure 1 shows the configuration of the servo system for 6.5H adjustment of the VCR.

Figure 2 is a pulse waveform diagram to illustrate the 6.5H adjustment of the VCR.

3 is a cross-sectional view of the tape to illustrate the 6.5H adjustment of the VCR;

FIG. 4 is a block diagram showing a 6.5H automatic adjustment apparatus of the present invention. FIG.

FIG. 5 is a detailed flowchart showing the 6.5H automatic adjustment method of the present invention. FIG.

DESCRIPTION OF THE REFERENCE NUMERALS

100: switching pulse detector 110: vertical synchronizing signal detector

120: variable resistor 140: motor

150: motor driving unit 160:

170: LED

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

FIG. 4 is a block diagram of a 6.5H automatic adjustment apparatus according to a preferred embodiment of the present invention.

4, a 6.5H automatic adjustment apparatus according to a preferred embodiment of the present invention includes a vertical sync signal detector 100 for detecting a vertical sync signal from a tape, a switching pulse detector 110 for detecting a switching pulse provided to the video head, A variable resistor 120 for finely adjusting the phase of a switching pulse corresponding to a resistance value, a voltage detector 130 for detecting a voltage value caught by the variable resistor 120, a motor for adjusting a resistance value of the variable resistor 120, A motor driving unit 150 for driving the motor 140, a motor driving unit 150 for adjusting the resistance value of the variable resistor 120 such that the interval between the switching pulse and the vertical synchronizing signal is 6.5H, A control unit 160, and an LED 170. [

First, the control unit 160 controls the LED 170 to turn on (S1), and controls the motor driving unit 150 to rotate the motor 140 in the reverse direction (S2). The motor driving unit 150 rotates the motor 140 in the reverse direction under the control of the controller 160 and the resistance value of the variable resistor 120 decreases as the motor 140 rotates in the reverse direction. Accordingly, the voltage value applied to the variable resistor 120 is reduced, and the voltage value applied to the variable resistor 120 is detected by the voltage detector 130 and provided to the controller 160.

The controller 160 reads the voltage value provided from the voltage detector 130 and controls the motor driving unit 150 when the voltage applied to the variable resistor 120 reaches the minimum value at step S4, (S5).

Then, the controller 160 provides the motor driver 150 with a forward driving control signal during the initial setting. The motor driving unit 150 rotates the motor 140 in the forward direction by the forward driving control signal provided from the controller 160 (S6). The resistance value of the variable resistor 120 becomes larger as the motor 140 rotates in the normal direction for a preset time.

Therefore, the phase of the switching pulse will be changed corresponding to the resistance value of the variable resistor 120. [ The switching pulse detector 110 detects the phase-converted switching pulse and provides the detected switching pulse to the controller 160 in operation S7. The vertical synchronization signal detector 110 detects the vertical synchronization signal from the tape and provides the vertical synchronization signal to the controller 160 S8).

The control unit 160 determines whether the difference between the phase-shifted switching pulse and the vertical synchronization signal is 381 to 445 μs (S9). This is because, in general, 1H is 63.5 占 퐏, 6.5H is 412.75 占 퐏, and there is a margin of about ± 0.5H in terms of the standard.

If the difference between the phase-shifted switching pulse and the vertical synchronizing signal is not within the range of 381 to 445 μs as a result of the determination, the controller 160 provides the forward driving control signal to the motor driving unit 150 again for a predetermined period of time (S6). It is repeatedly carried out (S7, S8, S9) to determine whether the difference between the phase-shifted switching pulse and the vertical synchronization signal is 381 to 445 占The control unit 160 controls the motor driving unit 160 to stop driving the motor 140 and then controls the LED 170 to turn on the LED 170 (S11).

If the difference between the phase-converted switching pulse and the vertical synchronizing signal is not included within 381 to 445 占 는데 even though the voltage supplied from the voltage detector 130 reaches the maximum value while repeating this process, Provides a reverse drive control signal to the motor driver 150 (S13).

The motor driving unit 150 drives the motor 140 in the reverse direction under the control of the controller 160 and the voltage value applied to the variable resistor 120 is reduced as the motor 140 is driven in the reverse direction.

The control unit 160 controls the motor driving unit 150 to stop the driving of the motor 140 when the voltage detected by the voltage detecting unit 130 reaches a midpoint between the minimum value and the maximum value (Step S11).

As described above, the present invention performs a 6.5H adjustment of the VCR automatically, which is very convenient.

Claims (2)

A 6.5H automatic adjustment apparatus of a VCR for adjusting a difference between a switching pulse provided to a video head of a VCR and a vertical synchronizing signal detected from a VCR tape so as to be 6.5H, comprising: a vertical synchronizing signal detecting unit (100); A switching pulse detector (110) for detecting a switching pulse provided to the video head; A variable resistor (120) for finely adjusting the phase of the switching pulse so as to correspond to a resistance value; A voltage detector 130 for detecting a voltage value across the variable resistor 120; A motor 140 for adjusting a resistance value of the variable resistor 120; A motor driving unit 150 for driving the motor 140; And a controller 160 for providing a drive control signal for adjusting the resistance value of the variable resistor 120 to the motor driver 150 so that the interval between the switching pulse and the vertical synchronization signal is 6.5H. 6.5H automatic adjustment device. A method for adjusting a 6.5H automatic adjustment method using an apparatus for adjusting a difference between a switching pulse of a video head whose phase is changed according to a resistance value of a variable resistor provided in a VCR and a vertical synchronous signal detected from a VCR tape, Converting a resistance value of the variable resistor so that a voltage value of the variable resistor is a minimum value; Detecting a difference between a switching pulse and a vertical synchronizing signal whose phase has been converted to correspond to the converted resistance while converting a resistance value of the variable resistor by a predetermined value of ohms (Ω) And stopping the resistance value conversion of the variable resistor if the difference between the synchronizing signals is within 381 to 445 占 퐏.