KR200195822Y1 - A noise arrasing apptatatus for vcr - Google Patents

Abstract

The present invention eliminates the noise generated when switching the video tape traveling direction from forward to reverse or vice versa when the video signal is reproduced by the video recorder (VCR), and controls before and after the change of direction. The present invention relates to a driving direction switching noise removing device capable of preventing a signal error, wherein the preamplifier (10, 20, 30, 40) amplifies and outputs a signal input from a head for reproducing an image signal recorded on a videotape. ); A head switching signal generator 70 generating a signal for selecting only one head according to an input control signal and a currently set mode (SP mode or EP mode); An inversion detecting unit (100a) for detecting the inversion time of the head switching signal; A luminance / chromatic signal angle processor (60) for processing an image signal output from a specific head selected by the head switching signal generator (70); A preamplifier 50 for amplifying and outputting a control signal; In response to the amplified output control signal, while controlling the signal output of the head switching signal generator 70, when the drive switching command is received, the time of inversion of the 30 Hz head switching signal output from the head switching signal generator 70 Control unit 100 for controlling the motor driving unit 80 and the head switching signal generator 70 on the basis of the reference, is configured to include, a desired specific screen through a clear screen without noise during the forward and reverse low-speed search In addition to making it more efficient to find, it is a very useful design to perform satellite servo control more accurately by using error-free servo control signals synchronized with control signals.

Description

V-Cal's tape running direction noise reduction device

The present invention relates to a tape driving direction switching noise control device of V-Cal. More specifically, the driving direction of a video tape is changed from forward to reverse or vice versa when a video signal is reproduced through a video recording player (VCR). The present invention relates to a tape running direction switching noise removing device of V-Cal that not only eliminates noise generated in a case but also prevents an error in the control signal before and after the change of direction.

Currently used in general, this is a four-head video recorder (VCR) appropriately selected according to the characteristics and operation mode of the track on which the signal is recorded, as shown in FIG. Pre-amplifiers 10, 20, 30, and 40 for amplifying and outputting signals input from the SP-A head, the SP-B head, the EP-A head, and the EP-B head, respectively; A 30 Hz head switching signal for periodically selecting only one pair (SP-A head and EP-B head, SP-B head and EP-A head) alternately among the four heads according to an input control signal, A head switching signal generator (70) for generating a separate playhead selection signal for selecting only one head again according to a currently set mode (SP mode or EP mode) among the pair of heads selected by the head switching signal; A luminance / chromatic signal processor 60 for processing an image signal output from a specific head selected by the head switching signal generator 70, and a preamplifier 50 for amplifying and outputting a control signal on a video tape input from a control head; ; According to a control signal amplified and output from the preamplifier 50, the head switching signal generator 70 controls the signal output, and according to a user request command input from a jog shuttle key provided in the external remote controller 90. And a control unit 100 for driving the capstan motor M in both directions by removing the motor driving unit 80.

In the video recording / reproducing apparatus configured as described above, when the videotape recorded video signal is reproduced, as shown in FIG. 4 (a), the control signal is set high according to the head switching control signal at a 30 Hz cycle having a duty ratio of 50%. In the level section, the SP-B head and the EP-A head are selected, and in the low level section, the SP-A head and the EP-B head are selected. In addition, the modulated signal output from the selected pair of heads is output from the head switching signal generator 70 according to the driving mode (stopped state or constant speed driving state) or playback mode (SP mode, EP mode) of the video tape. By the playhead selection signal, only the signal output from the SP-B head or the EP-A head in the high level section is input to the luminance / chromatic signal processing unit 60, and in the low level section the EP-B. Only the signal output from the head or the SP-A head is input to the luminance / chromatic signal processor 60.

Type A azimuth on a video tape in which tracks having type A azimuth and type B azimuth are sequentially recorded with each other by the head switching signal and the reproduction head selection signal. A track recorded by a head having a type A azimuth is reproduced by a head having a type A azimuth, and a track recorded by a head having a type A azimuth is reproduced by a head having a type A azimuth. It is output on the screen of the display device (not shown).

If the user rotates the jog shuttle key of the remote controller 90 to the left or the right during the output of the video screen as described above, the controller 100 controls the motor driving unit 80 in the rotation direction selected by the user. Accordingly, by rotating the capstan motor M in the forward or reverse direction, it is possible to reproduce and view the recorded image while driving the video tape in the desired direction.

However, in the conventional driving direction switching method performed by the video recording player as described above, when the driving direction switching signal is input from the user via the jog shuttle key, the control unit 100 simultaneously switches the input of the switching signal, that is, switching. Irrespective of the state of the head switching signal and the reproduction head selection signal at the time of signal input, the motor driving unit 80 was controlled to switch the rotation direction of the capstan motor M. FIG.

Therefore, in a state where the video signal being reproduced from one track (video signal for one field) is not completely scanned on the screen, the video head reproduces the video signal while moving backward along the track. As a result, there was a problem that noise occurs at the switching point on the screen.

In addition, when the signal recorded on the control track of the video tape reproduced through the control head is detected, the rising point and the falling point are periodically detected alternately, and this signal is passed through the Schmitt trigger circuit and the high level signal and the low level are detected. The signal is periodically converted to a pulse signal, which is used to control the phase of the capstan motor. In the conventional driving direction switching method, the signal is raised to the point immediately before the driving switching signal input as shown in FIG. 4 (c). When (P ₁ ) is detected, as the rising point (P ₂ ) is repeatedly detected, the state of the signal used for phase control at the rising point detection point (P ₂ ) as shown in FIG. 4 (d). Is not inverted and the high level state is maintained until the next falling point detection point (P ₃ ) so that an error occurs in the servo control at this time. There was a problem that there is a risk of spreading to the servo control afterwards.

Accordingly, the present invention has been made to solve the above problems, and provides a tape running direction switching noise removing device of V-Cal to remove the noise on the screen generated when the moving direction of the video tape is changed. That is,

Another object of the present invention is to provide a V-Tal tape running direction switching noise removing device capable of eliminating erroneous detection of a control signal generated when the moving direction of a video tape is changed.

1 is a block diagram showing an embodiment of an image recording and reproducing apparatus to which the driving direction switching noise removing device according to the present invention is applied.

FIG. 2 is a timing diagram of the signals of the main part of FIG. 1 before and after the turn signal input through the jog shuttle.

(a) is a headswitching signal,

(b) is a positive (+) reverse direction switching signal of the motor applied to the motor driving unit,

(c) is a control signal detected during reproduction,

(d) is a reset signal for correcting the non-inverting error of the servo control pulse by the control signal of (c),

(e) is a phase signal control pulse signal of the capstan motor whose non-inverting state is removed by the reset signal of (d),

3 shows the configuration of a conventional video recording and playback device.

4 is a timing diagram of the main part signals of FIG. 3 before and after the turn signal input through the jog shuttle key.

(a) is a headswitching signal,

(b) is a positive (+) reverse direction switching signal of the motor applied to the motor driving unit,

(c) is a control signal detected during reproduction,

(d) is a pulse signal for phase servo control of a capstan motor synchronized with the control signal of (c).

* Explanation of symbols for main parts of the drawings

10,20,30,40,50: amplifier 60: luminance / chromatic signal processing unit

70: head switching signal generator 80: motor drive unit

90: remote control 100: microcomputer

100a: reverse detection unit M: capstan motor

In order to achieve the above object, the tape running direction switching noise removing device of V-Cal according to the present invention comprises: an operation key for switching the running of the tape in the forward or reverse direction and / or commanding the driving; A motor driving unit for driving the capstan motor to switch tape running and direction; Head switching signal generating means for outputting a head switching signal of a predetermined period; And control means for outputting a tape driving direction switching signal to the motor driving unit in response to the inversion detection time of the head switching signal output from the head switching signal generating means when the tape driving direction switching command is input by the operation key. It is characterized by being constructed,

The tape running direction switching noise eliminating apparatus of V-Cal according to the present invention is characterized in that the control means forcibly inverts and outputs the level of the control signal to be reproduced when the tape running direction is switched.

In the tape running direction switching noise removing device of V-Cal according to the present invention, which is configured as described above, when a user inputs a driving direction switching of the video tape, that is, switching the playing direction, during the playback, the control means switches. Rather than switching the running direction of the tape at the same time as the input of the command, the reversing detecting means for delaying the input switching command once, i.e., detecting the reversal of the head switching signal output from the signal generating means, i.e., the control means. By the inversion detecting means which may be included, it waits until the inversion of the head switching signal is detected.

Subsequently, if the inversion of the head switching signal is detected by the inversion detecting means, it means that one field of video signal has been completely scanned on the screen of the external image display device, so that the control means triggers at the time of inversion of the switching signal. By changing the driving direction of the video tape, it is possible to prevent the noise in the middle part of the screen caused by the deviation of the driving path of the head as the driving direction is changed when one image field is not scanned.

In addition, if the level of the phase control pulse synchronized with the control signal is forcibly inverted at the same time as the direction change, the error of the phase control signal due to the detection of the control signal detected immediately before the direction change again after the direction change can be eliminated. .

Hereinafter, the operation of an embodiment of the tape running direction switching noise removal device of V-Cal according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a view showing the configuration of an embodiment of a V-real tape running direction switching noise removing device according to the present invention, looking at the configuration of Figure 1 is output from a video head that performs the same function as the configuration of Figure 3 Preamplifiers 10, 20, 30, and 40 for video signals; A head switching signal generator 70; Reverse detection unit 100a; A luminance / chromatic signal processor 60; A preamplifier 50 for a control signal output from the control head; And a control unit 100, wherein the control unit 100 is based on the inversion time of the 30 Hz head switching signal output from the head switching signal generator 70 when the driving change command is received. 80 and the head switching signal generator 70 is to be controlled.

In one embodiment of the driving direction switching noise removing device according to the present invention configured as described above, a signal for changing the direction of the capstan motor (M) from the user via the jog shuttle key during the playback of the video tape remote control receiving circuit (Fig. (Not shown) (2 (b) also ①). The controller 100 continuously detects the head switching signal input from the head switching signal generator 70 without performing a control operation immediately for the direction change request.

The control unit 100 does not immediately perform the positive (+) switching operation of the capstan motor (M) when the driving direction of the video tape is changed when the head switching signal is not inverted. The head path on the track is shifted when the video signal of one field that is being scanned on the screen is not reproduced by the selected head in the head switching signal section of the screen. This is because noise is generated at the position of the image. The controller 100 waits for the 30 Hz head switching signal input from the head switching signal generator 70 to be inverted immediately after the direction change signal is input.

Subsequently, when the inversion of the head switching signal is detected by the inversion detecting unit 100a (second (a) in FIG. 2), the control unit 100 immediately switches the direction change signal (second (b) in FIG. ③ viewpoint). The motor driving unit 80 is applied to the motor driving unit 80 and thus the motor driving unit 80 rotates in a reverse direction by switching the flow of the driving current applied to the capstan motor M. That is, after the video signal is reproduced at the time of input of the direction change signal, the predetermined head which is being output is reproduced to the end of the track, that is, after the video signal of one field is completely scanned on the screen, the driving direction of the video tape is not changed. By switching, the noise generated in the middle of the screen can be prevented.

In addition, the control unit 100 forcibly applies a pulse signal (second (e) diagram) output in synchronization with the input control signal at the time of inputting the inverted signal of the head switching signal (second (b) diagram ① time point). A reset signal is applied to the head switching signal generator 70 in order to invert it. (2 (d) is a point in time ④). At the time when the reset signal is applied as shown in Fig. 2, the high level state of the servo control pulse synchronized with the control signal is forcibly inverted to the low level state (second (e) in Fig. 5). Accordingly, the state reversal of the servo control pulses is made without error by the detection of the subsequent control signal, so that the servo control by this signal can be performed without error even when the driving direction is changed and afterwards.

The tape running direction switching noise elimination device of V-Cal according to the present invention, which is configured and operated as described above, can more effectively find a specific screen desired through a clear screen without noise caused by switching at a low speed search in the forward and reverse directions. Of course, it is a very useful design to more accurately perform the phase servo control of the capstan motor by eliminating the inversion error of the servo control pulse by the detected control signal.

Claims (2)

Operation keys for switching the running of the tape in the forward or reverse direction and / or commanding the running; A motor driving unit for driving the capstan motor to switch tape running and direction; Head switching signal generating means for outputting a head switching signal of a predetermined period; And control means for outputting a tape driving direction switching signal to the motor driving unit in response to the inversion detection time of the head switching signal output from the head switching signal generating means when the tape driving direction switching command is input by the operation key. V-Cal tape running direction switching noise canceller configured. The apparatus of claim 1, wherein the control means forcibly inverts and outputs the level of the control signal to be reproduced when the tape travel direction is changed.