KR100202026B1 - Method for detecting viss in video cassette recorder - Google Patents

Abstract

The present invention relates to a video cassette recorder, comprising: a step (31, 32, 33) of determining whether a seek mode is set and fast-reversing until a search signal is detected when a search mode is set; (34, 35) of judging whether the seek flag is in the reset state (0) when the bus signal is detected, thereby switching the search flag to the reset state and the stop mode, and setting the count value to 0; Counting the length of the tape traveled by the inertial force after the switching of the stop mode, and advancing at a low speed (36, 37) until the count value becomes "0" when the running of the tape by the inertia force is stopped; Returning to a playback mode for a predetermined time when the count value becomes '0', setting (1) a search flag, and returning to a step (31) for determining whether to set a search mode; (Step 40) to step 31 of judging whether the search mode is set after resetting the search flag if the search flag is set to 1 after detection of the bus signal.

That is, the present invention has the effect of accurately detecting the bus signal for performing the search mode by controlling the detection of the bus signal in the search mode using the flag.

Description

Method of detecting a video signal of a video cassette recorder

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a video cassette recorder (hereinafter referred to as a VCR), and more particularly, to a method of displaying a time when a video signal is reproduced after a screen search using a VISS will be.

The VIS signal means a signal unified with an index signal in the VHS system VCR. This signal changes the waveform of the control signal recorded on the control track of the video tape (i.e., the duty of the original control signal is 6 : 4 or the duty ratio of the control signal is changed to 4: 6 or the like, and 64 control signals whose duty ratio is modified are used as the bus signal).

With the use of such a video signal, the conventional VCR can easily search a video tape section desired by the user. That is, the user records a video signal in a desired section of the tape and detects the video signal at the time of playback, thereby promptly searching for a desired tape section. In addition, in a conventional VCR, when a plurality of video signals are recorded on a tape, only a section in which a video signal is recorded is sequentially reproduced for a predetermined time, thereby enabling a user to quickly search for a desired tape section . A method of performing such a search function will be described with reference to FIG.

As shown in FIG. 1, a plurality of video signals VS1 to VS3 are recorded on a video tape. The video signals VS1 to VS3 have control signals whose duty ratio is changed from 4: 6 to 64 Are formed.

At this time, when the user drives the VCR in the search mode at the position P1 of the tape, the VCR rewinds. When the VIS signal VS2 is detected during the high-speed reverse operation, the VCR switches from the position P2 where the duty ratio is modified to 21 counts, to the stop mode. However, in this case, the drum motor and the reels continue to rotate for a predetermined time due to the torque inertia at the time of high-speed reverse, and the time point at which the running of the tape stops is the time point (P3)

Then, the VCR is switched from the stop mode to the playback mode, and is driven for a predetermined time to reproduce a video signal from the tape section in which the video signal VS2 is recorded to a predetermined time (position P4 in this embodiment) . Then, the VCR is driven again in the high-speed reverse mode again at the position P4, but does not detect the bus signal for a predetermined time, and this predetermined time (hereinafter referred to as the bus detection limit time). After the elapse of the lapse of the bus signal VS3, the bus signal VS3 is detected and the above process is repeated. Here, the reason why the VCR does not detect thevis signal for a predetermined time when the VCR is fast-backward again at the position P4 is that, when it is detected again from the position P4 as seen from the figure, VS2) is detected again.

However, there is a problem in that the conventional method using the detection time limit of the bus in order to avoid redetecting the detected bus signal during the search mode may cause an error in detection of the bus signal. For example, when the vis detection time limit is too short, a detected bus signal (VS2 in the figure) may be detected again. If the bus detection time limit is too long, the bus signal VS3 is not detected It can happen.

SUMMARY OF THE INVENTION The present invention has been made in order to solve such a problem, and it is an object of the present invention to provide a method of detecting a vision signal of a VCR capable of safely detecting a vision signal in a search mode of a VCR.

A method of detecting a visibility signal of a VCR according to the present invention comprises the steps of: determining whether a search mode is set and, if the search mode is set, fast-reversing until a vis signal is detected; Determining whether the search flag is in the reset state when the bus signal is detected, switching the search flag to the reset state and the stop mode, and setting the count value to zero; Counting the length of the tape traveled by the inertial force after the switching of the stop mode and advancing at low speed until the count value becomes '0' when the running of the tape due to the inertia force is stopped; When the count value becomes '0', returning to the step of driving in the reproduction mode for a predetermined time, setting the search flag, and determining whether to set the search mode; And if the search flag is set to (1) after detection of the bus signal, determining whether to set the search mode after resetting the search flag is included.

FIG. 1 is a view for explaining a screen searching method using a video signal in a conventional video cassette recorder.

FIG. 2 is a block diagram of a video cassette recorder that performs a video signal detection method according to the present invention;

3 is a flow chart of a video signal detection method of a video cassette recorder according to the present invention;

DESCRIPTION OF THE REFERENCE NUMERALS

11: recording processing system 12: reproduction processing system

13: Deck 14: Microcomputer

15: Key metrics

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

2 is a block diagram of a VCR according to the present invention and includes a recording processing system 11 and a reproduction processing system 12, a deck 13, a microcomputer 14, and a key matrix 15 as shown in FIG. .

The recording processing system 11 records and processes the video and audio signals applied from a tuner or an external input terminal (not shown) under control of the microcomputer 14 and applies it to the deck 13, The video signal of the recording processing system 11 is recorded on the video tape under the control of the control unit 14 or the signal of the video tape is read and applied to the reproduction processing system 12. [ At this time, the deck 13 reads the control signal recorded on the control track of the tape and applies it to the microcomputer 14. The microcomputer 14 detects the bus signal from the control signal and drives the VCR Respectively.

The reproduction processing system 12 reproduces the video signal of the video tape detected from the deck 13 and applies it to a display device such as a monitor (not shown).

The microcomputer 14 controls the driving of the recording processing system 11, the reproduction processing system 12 and the deck 13 in this manner. The mode for controlling the driving in this manner is a mode in which among the various function keys of the key metrics 15 It is controlled by the user, i.e., in response to the pressed key.

FIG. 3 shows a flow diagram of a program stored in the microcomputer 14 for carrying out the present invention.

First, the microcomputer 14 determines whether the search mode is set according to the key of the key matrix 15 (step 31), and if the search mode is set, the microcomputer 14 proceeds to step 32. [

In step 32, the microcomputer 14 determines whether the bus signal is detected (step 33) and determines whether the search flag is in the reset state (step 34) when the bus signal is detected (step 34) . If it is determined in step 34 that the seek flag is in the reset state, the microcomputer 14 proceeds to step 35 to set the count value of the internal counter to 0 while switching the VCR to the stop mode.

At this time, even if the stop mode is set in step 35, the tape can not stop the running due to inertia of the capstan motor or the like, and continues running for a predetermined time. The microcomputer 14 measures the length of the tape traveled by the inertial force by counting the control pulse using a counter.

When the running of the tape due to the inertial force is stopped, the microcomputer 14 advances the VCR at a low speed until the value of the counter becomes '0' at steps 36 and 37. That is, as described above, the tape traveled by the inertia force is returned to the position where the vis signal is detected. Then, the microcomputer 14 drives the VCR in the reproduction mode for a predetermined time (step 38), sets the above-described search flag to 1, and then returns to step 31 (step 39).

That is, when one bus signal is detected by the search mode, the microcomputer 14 sets the search flag after performing the playback mode for a predetermined time from the position where the bus signal is detected.

In this state, the microcomputer 14 is driven in the fast reverse mode with the search flag being set, and the bus signal will be detected again in step 33 at this time. However, in this case, since the search flag is set, the microcomputer 14 proceeds to the step 40, and after the search flag is reset at the step 40, the microcomputer 14 returns to the step 31 again.

That is, in the present invention, when one vis signal is detected by the search mode, the microcomputer 14 sets the search flag after performing the reproduction mode for a predetermined time from the position where thevis signal is detected, The search flag is reset by the bus signal first detected by the backward signal, and then the stop and playback mode is performed by the second bus signal.

As described above, the present invention has an effect of accurately detecting the bus signal for performing the search mode by controlling the detection of the bus signal in the search mode using the flag.

Claims (1)

A method of driving a video cassette recorder, comprising: (31,32,33) a step of determining whether a seek mode is set and fast-reversing until a video signal is detected when a search mode is set; (34, 35) of judging whether the search flag is in the reset state (0) when the vis signal is detected, switching the search flag to the reset state and the stop mode, and setting the count value to 0; Counting the length of the tape traveled by the inertial force after the switching of the stop mode and advancing at a low speed until the count value becomes '0' when the travel of the tape due to the inertial force is stopped; Returning to a playback mode for a predetermined time when the count value becomes '0', setting (1) the search flag, and returning to a step (31) of determining whether to set the search mode; (30) to a step (31) of judging whether to set the search mode after resetting the search flag if the search flag is set to 1 after detection of thevis signal. Way.