KR100205819B1 - Method of preventing video signal from over recording - Google Patents

Abstract

The present invention proposes a video signal recording method capable of preventing the duplication of video signal at the initial recording area when video signals are recorded on a video tape using VSI.

The technical core of the present invention is to supply an oscillation signal for erasing video and audio signals on a videotape to the full-amplification head in accordance with VSI's video tape recording mode execution start, and after generating the oscillation signal for full-width erasing at this stage. And supplying a video signal for recording to a video head provided on the head drum with a predetermined delay time.

Description

How to Prevent Video Signal Overwriting

1 is an internal circuit diagram of VSI for explaining a process of recording and reproducing a video signal in a general VSI.

2 is a schematic structural diagram of a video tape traveling system for explaining the cause of signal overlap in the video signal recording process using VSI.

3 is a hardware diagram for implementing the present invention.

4 is a flow chart for explaining the operation of the present invention.

* Explanation of symbols on the main parts of the drawings

100: main PCB 110: power supply

115: power failure judgment circuit 120: audio recording and playback section

130: timer ciscon servo unit 131: system control (microcomputer)

140: video recording and playback unit 160: head amplifier module

161: delay unit 162: IF block

163 tuner 164 RF modulator

165: input selector 170: control head

171: head drum 174: voice head

175: video head 176: full-width head

177: mute head

The present invention relates to a video signal superimposition recording prevention method capable of avoiding a redundant recording phenomenon of a signal occurring near a recording start of a video tape when recording and recording a video signal and an audio signal using VSI.

Video and audio signals from external sources or over-the-air broadcast signals received through an internal television tuner are recorded on the video tape, and the video and audio signals recorded on the video tape are output through the television screen. The video signal recording and reproducing process of VSI will be described with reference to the internal circuit diagram of VSI shown in FIG. 1 as follows.

As referred to herein, the VSI circuit is largely divided into a main PCB 100 and a logic PCB 200.

The main PCB 100 includes a power supply unit 110, an audio recording and reproducing unit 120, a timer scissor servo unit 130, an image recording and reproducing unit 140, and the like.

The power supply unit 110 includes a noise filter 111 installed on a power line to remove noise components on an AC input voltage input through the power cord 114 and a commercial AC input voltage passing through the noise filter 111. Switching circuit 112 for generating a high-frequency switching voltage to obtain a high-quality voltage from the constant voltage circuit 113 for generating a stable VSI circuit operating voltage in response to the switching voltage output from the switching circuit.

The audio recording and reproducing unit 120 may include an equalization amplifier 123 for amplifying a voice signal read and input by the voice head 174, and an amplification of an output signal of the equalization amplifier 123 to the A / V jack 180. A line amplifier for transmitting to the voice output terminal 182 and the voice output terminal of the skat jack 190, and amplified by receiving the audio input signal of the voice input terminal 184 of the A / V jack and the voice input terminal of the scott jack And a recording amplifier 122 for amplifying the output signal of the line amplifier 121 and outputting the amplified signal to the voice head 174, and for the full-amplification head 176 and the audio mute ed 177. OSC 124 for supplying the oscillation signal for.

The timer ciscon servo unit 130 receives the data from the remote control receiver 220 in the logic PCB 200 and exchanges data with the timer through the digitron driver 230. A system control (microcom) that exchanges data between the two and receives a tape control signal by the control head 170 and outputs a control signal to be recorded on the control track of the video tape during tape recording to the control head 170 side. 131 and the respective drive servos 133 and gapstan servos for driving the drive motor 171, the tapstan motor 172, and the loading motor 173 according to the control output of the system control 131. 134, a loading motor driver 135.

The video recording and reproducing unit 140 includes a signal path including an LPF 141 pre-emphasis circuit 142 and an FM modulator 143 to record an image signal coming from the input selector 165, a BPF 145, A signal path comprising an automatic chroma level control (ACC) 146, a converter 147, and a first mixer 144 for mixing the two signals passing through these signal paths and transmitting the mixed signals to the head amplifier module 160 side. .

The video recording / reproducing unit 140 also includes a signal processing path of the head amplifier module 160 including a DOC 148, a demodulator 149, and a de-emphasis circuit 150, a converter 152, and a BPF 153. And a second mixer 151 for mixing a signal processing path of the head amplifier module, a video signal passing through these two signal paths, and a playback amplifier 154 for amplifying the video playback signal output from the second mixer. do.

The head amplifier module 160 has four image rotating heads 175. In the standard recording and reproducing method, the image amplifier includes two image rotating heads.

A part of the image reproduction signal output from the image recording / reproducing unit 140 is output to the image output terminal 181 of the A / V jack 180, and the other part is modulated by the RF modulator 164 to output the RF output terminal 196. Configure output to The RF signal input to the antenna input terminal 195 of the RF modulator 164 is converted into a video and audio signal through the tuner 163 and the IF block 162, and thus, the first and second switches of the input selector 165. One end of each of the first and second switches 166 and 167 of the input selector 165, and the video and audio inputs 183 and 184 of the A / V jack 180 and the skat. The video / audio signal input through the video and audio input terminal of the jack 190 is connected to be applied.

The audio signal and the video signal output from the first and second switches 166 and 167 of the input selector 165 are respectively the LPF 141 in the line amplifier 121 and the video recording / reproducing unit 140 in the audio recording / reproducing unit 120. ) To be transmitted to the BPF 145.

The logic PCB 200 includes a key matrix 240 for inputting a key signal of a function selection key provided on an external front panel of the VSI, and key timer signal data received from the key matrix 240. Digitron driver 230 for transmitting to the timer 132 of the servo unit 130 and receiving data from the timer, and for displaying various characters and numbers according to the output of the digitron driver 230. Tron 210 and a remote control receiver 220 for receiving a control key input signal from the remote control and transmitting the control data to the timer 132.

The operation relationship of the VSI circuit configured as described above is as follows.

The power supply unit 110 of the main PCB 100 to supply the stabilized operating voltage to each portion of the VSI is a noise filter 111 of the 60Hz (or 50Hz) commercial voltage of the power supply unit 110 through the power cord 114 After inputting to the switching circuit 112, the switching circuit converts the input voltage frequency into a high frequency of several tens of KHz, and then converts the input voltage frequency into a necessary switching voltage and transmits it to the constant voltage circuit 113.

As a result, the constant voltage circuit generates a stable operating voltage to be supplied to each part of the VSI.

When such an operating voltage is applied to VSI, the audio and video signals selected by the audio and video switches 166 and 167 of the input selector 165 are supplied to the audio recording and reproducing unit 120 and the video recording and reproducing unit 140, respectively. .

The voice switch 166 of the input selector 165 selects an audio signal input through the voice input terminal of the skat jack and the A / V jack and an audio signal generated in the IF block 162, and also the image switch 167 thereof. Selects the video signal of the video tape coming in through the video input terminal of the skat jack and the A / V jack and the air broadcast video signal generated in the IF block 162.

Prior to this, the broadcast channel signal by the tuner 163 is applied to the IF block 162, and the A / V signal or antenna input terminal 195 modulated by the RF modulator 164 to the RF signal is applied to the tuner 163. The antenna signal inputted through is applied.

The voice signal applied to the voice recording and reproducing unit 120 is amplified by the recording amplifier 122 through the line amplifier 121 and then transmitted to the voice head 174 to record the corresponding voice signal on the video tape.

The video signal applied to the video recording / reproducing unit 140 includes a first signal path consisting of the LPF 141 pre-emphasis circuit 142 and the FM modulator 143, the BPF 145, the ACC 146, and the converter 147. The second signal paths are respectively configured to be mixed in the first mixer 144 and applied to the head amplifier module 160 having two or four image heads 175. To be recorded on a videotape.

In recording such video and audio signals, oscillation signals from the OSC 124 are applied to the full-width erasing head 176 and the audio muting ped 177 so that the previous video and audio signals recorded on the videotape are immediately before recording. It is being deleted.

On the contrary, as the video tape is reproduced, the audio reproduction signal on the video tape read by the audio head 174 passes through the equalization amplifier 123 and the live amplifier 121 in the audio recording and reproducing unit 120 in turn. And the video signal on the video tape read by the video head 175 through the head amplifier module 160 and the video recording / reproducing unit 140 through the A / V jack. Each of the image output terminal 180 and the scart jack 190 is output.

In addition, the audio output signal of the audio recording and reproducing unit 120 and the video output signal of the video recording and reproducing unit 140 which have passed through the oscillation circuit 161 are modulated into RF signals by the RF modulator 164 and output to the RF output terminal 196. do.

The key input signal on the front panel of VSI, which enters the key matrix 240 on the logic PCB 200, passes through the digitron driver 230 to the timer 132 in the timer ciscon servo unit 130. The display signal generated by the timer 132 is applied to the system control 131 along with the received signal, and is displayed on the digitron 210 through the digitron driver 230.

The system control 131 controls the drum servo 133, in response to the VSI control signal from the remote control receiver or key matrix input through the timer 132 and the control signal from the control head 170 installed in the tape odometer. Each drum motor 171, the capstan motor 172, and the loading motor 173 are controlled through the capstan servo 134 and the loading motor driver 135.

However, a problem in the VSI operating in this way is that when the image signal is recorded on the video tape, an overlapping section of the image recording, which partially overlaps with the previous image signal recording portion, occurs.

The overlapping section of the video signal recording on the video tape is generated at the portion placed between the full width erasing head and the rotating head provided on the rotating drum cylinder.

FIG. 2 is a schematic structural diagram of a video tape traveling system, which will be described below with reference to this description.

In the standard method, two image heads 175 are mounted on the side surface of the rotating head drum 171 having a diameter of 62 mm at intervals of 180 degrees, and the head drums rotate 30 times per second.

The video tape 260 is driven in a state in which the head drum 171 is wound over 180 °. The head drum 171 is inclined with respect to the chassis and is also inclined with respect to the tape traveling in parallel with the chassis. Form.

The tape guide 257 for guiding the video tape 260 is provided in the lower cylinder of the head drum 171 fixed to the chassis.

At the position approaching the tape guide formed in the head drum 171, the respective loading on the pulley side and the take-up side of the head drum to prevent the video head from being able to accurately trace the video track as the tape moves up and down. Posts 255 and 256 are installed.

The loading posts 255 and 256 pull out and move the video tape 260 at the time of tape loading, which are each made up by pairs of inclined posts and posts perpendicular to each other.

Impedance rollers 254 and 258 are provided on both sides of the tape supply side and the take-up side that pass the loading posts 255 and 256 from the head drum 171, respectively.

These impedance rollers 254 and 258 stabilize tape running and prevent jitter from being shaken by the play signal.

The driving path of the videotape is as follows.

The video tape 260 drawn out from the supply reel 251 of the tape cassette comes into contact with the full-width erasing head 176 via the tension arm and the back tension post 253.

The full-width erasing head 176 receives the high frequency signal current supplied from the OSC 124 shown in FIG. 1 at the time of signal recording to erase the video signal recorded on the tape.

The tape is then recorded by the image head 175 at the rotating head drum 171 via the impedance roller 254 and the loading post 255 and then through the loading post 256 and the impedance roller 258. .

The video tape passed through the impedance roller 258 reaches the mute head 177 and the voice and control heads 174 and 170.

Since the oscillation signal of the OSC 124 supplied to the full-width mute head 176 is supplied to the voice mute head 177, the voice track of the video tape 260 is erased.

The voice and control head has a control head 170 disposed on its lower side and a voice head 174 on its upper side to record and reproduce voice and control signals on each track.

The voice mute head is not used in normal cases because of the full mute head, and is used only for voice dubbing.

The video tape is then wound around the take-up reel 262 through the capstan 261 and the pinch roller 259 for stably running the tape.

As described above, in the tape traveling system, when the video signal is recorded, the erasing current and the image recording signal are simultaneously supplied to the full width erasing head 176 and the image head 175, respectively. In the video tape, new video signals are duplicated and recorded without the previous recording contents being erased.

SUMMARY OF THE INVENTION An object of the present invention is to provide a video signal recording superimposition prevention method, in which video signal recording using VSI can avoid duplication of video signals at the beginning of recording.

A feature of the present invention is that the video head supply video signal installed on the head drum is delayed at a predetermined time interval compared to the video tape video and audio signal erasing oscillation signals supplied to the full-width erasing head when the video tape recording mode is started. This prevents duplication of image signals from occurring in the tape section between the full-width erasing head and the rotating video head on the travel path.

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

3 is a system block diagram of VSI for realizing the present invention.

As referred to herein, the power supply unit 110 in the main PCB 100, the noise filter 111 is installed on the power line to remove the noise component on the AC input voltage input through the power cord 114, and The switching circuit 112 generates a high frequency switching voltage to obtain a high quality voltage from the commercial AC input voltage passing through the noise filter 111, and a stable VSI circuit operating voltage is received in response to the switching voltage output from the switching circuit. And a constant voltage circuit 113 for generation.

The audio recording and reproducing unit 120 may include an equalization amplifier 123 for amplifying a voice signal read and input by the voice head 174, and an amplification of an output signal of the equalization amplifier 123 to the A / V jack 180. A line amplifier for transmitting to the voice output terminal 182 and the voice output terminal of the skat jack 190, and amplified by receiving the audio input signal of the voice input terminal 184 of the A / V jack and the voice input terminal of the scott jack And a recording amplifier 122 for amplifying an output signal with the line amplifier 121 and outputting the signal to the voice head 174, and for the full-amplification head 176 and the voice muting head 177. OSC 124 for supplying the oscillation signal for.

The timer ciscon servo unit 130 only receives data from the remote control receiver 220 in the POB 200 and sends and receives data through the digitron driver 230. The system control (microcomm) which exchanges data between the two and receives the tape control signal by the control head 170 and outputs the control signal to be recorded on the control track of the video tape during tape recording to the control head 170 side (microcom) 131 and the respective drive servos 133 and capstan servos for driving the drive motor 171, the capster motor 172, and the loading motor 173 according to the control output of the system control 131. 134, a loading motor driver 135.

The video recording and reproducing unit 140 includes an LPF 141, a pre-emphasis circuit 142, and an FM modulator 143 to record a video signal input from the input selector 165 through the delay unit 161. A signal path, a signal path comprising a BPF 145, an automatic chroma level control (ACC) 146, a converter 147, and two signals passing through these signal paths are mixed and transmitted to the head amplifier module 160. The first mixer 144 is included.

In addition, the video recording / reproducing unit 140 includes a signal processing path of the head amplifier module 160 including a DOC 148, a demodulator 149, and a de-emphasis circuit 150, a converter 152, and a BPF 153. And a second mixer 151 for mixing a signal processing path of the head amplifier module, a video signal passing through these two signal paths, and a playback amplifier 154 for amplifying the video playback signal output from the second mixer. do.

The delay unit 161 is configured to determine the delay timing of the video signal by the output of the microcomputer 131 in the timer sheath servo unit 130.

The head amplifier module 160 may have two or four image rotating heads 175. In the standard recording and reproducing method, the image rotating heads are composed of two.

A part of the image reproduction signal output from the image recording / reproducing unit 140 is output to the image output terminal 181 of the A / V jack 180, and the other part is modulated by the RF modulator 164 to output the RF output terminal 196. Configure output to

On the other hand, the RF signal input to the antenna input terminal 195 of the RF modulator 164 is converted into a video and audio signal through the tuner 163 and the IF block 162, the first and second switches of the input selector 165 One end of each of the first and second switches 166 and 167 of the input selector 165, and the video and audio inputs 183 and 184 of the A / V jack 180 and the skat. The video and audio signals input through the video and audio input terminals of the jack 190 are connected to each other.

The audio signal output from the first switch 166 of the input selector 165 is directly connected to the line amplifier 121 in the audio recording and reproducing unit 120, and the video signal output from the second switch 167 is It is connected to the LPF 141 and the BPF 145 in the video recording and reproducing unit 140 via the delay unit 161.

Only the PCB 200 receives a key matrix 240 for inputting a key signal of a function selection key provided on an external front panel of VSI, and receives a key input signal data from the key matrix 240 and generates a timer signal. Digitron driver 230 for transmitting to the timer 132 of the servo unit 130 and receiving data from the timer, and for displaying various characters and numbers according to the output of the digitron driver 230. Tron 210 and a remote control receiver 220 for receiving a control key input signal from the remote control and transmitting the control data to the timer 132.

A method of preventing the occurrence of the dual recording area of the present invention based on the hardware configuration of the VSI system will be described in detail below.

The power supply unit 110 of the main PCB 100 to supply the stabilized operating voltage to each portion of the VSI is, the commercial voltage of 60Hz (or 50Hz) through the power cord 114 is a noise filter of the power supply unit 110 ( When input to the switching circuit 112 via 111, the switching circuit converts the input voltage frequency into a high frequency of several tens of KHz, and then converts the input voltage frequency into a switching voltage of a required size and transmits it to the constant voltage circuit 113.

As a result, the constant voltage circuit generates a stable operating voltage to be supplied to each part of the VSI.

When such an operating voltage is input to each internal circuit of VSI's system, the audio signal selected by the voice switch 166, which is the first switch of the input selector 165, is supplied to the voice recording / reproducing section 120. The video signal selected by the video switch 167 which is the second switch of the selector 165 is supplied to the video recording / reproducing unit 140.

The voice switch 165 of the input selector 165 selects an audio signal input through the voice input terminals of the skat jack and the A / V jack and an air broadcast video signal generated in the IF block 162.

Prior to this, the broadcasting station signal by the tuner 163 is applied to the IF block 162, and the A / V signal or antenna input terminal 195 modulated by the RF modulator 164 to the RF signal is applied to the tuner 163. The antenna signal inputted through is applied.

The voice signal applied to the voice recording and reproducing unit 120 is amplified by the recording amplifier 122 through the line amplifier 121 and then transmitted to the voice head 174 to be recorded as a corresponding voice signal on the video tape.

The video signal applied to the video recording / reproducing unit 140 includes a first signal path consisting of the LPF 141, the pre-emphasis circuit 142, and the FM modulator 143, the VPF 145, the ACC 146, and the converter ( It is applied to the head amplifier module 160 having two or four image heads 175 mixed in the first mixer 144 via the second signal paths formed of 1470, and the corresponding image signal is applied to the image head. Will be recorded on the videotape.

In recording such video and audio signals, the oscillation signal from the OSC 124 is applied to the full-width erasing head 176 and the audio-clearing head 177, so that the previous video and audio signals recorded on the videotape are immediately before recording. Is being deleted.

On the contrary, as the video tape is reproduced, the audio reproduction signal on the video tape read by the audio head 174 is sequentially passed through the equalization amplifier 123 and the line amplifier 121 in the audio recording and reproducing section 120. 180) and the video signal output to the audio outputs of the skat jack 190, and read out by the video head 175 through the head amp module 160 and the video recording / reproducing unit 140 through the A / V. Each of the jack 180 and the scart jack 190 will be output to the video output terminal.

In addition, the audio output signal of the audio recording and reproducing unit 120 and the video output signal of the video recording and reproducing unit 140 which have passed through the oscillation circuit 161 are modulated into an RF signal by the RF modulator 164 to the RF output terminal 196. Will be output.

The key input signal on the front panel of VSI entering the key matrix 240 on the logic PCB 200 is passed through the digitron driver 230 to the timer 132 in the timer ciscon servo unit 130. The display signal generated by the timer 132 is applied to the system control 131 along with the received signal, and is displayed on the digitron 210 through the digitron driver 230.

The control signal from the system control head 170 is input in accordance with the control signal from the remote control receiver or key matrix input through the timer 132 and the control signal from the control head 170 installed in the tape odometer. The system control 131 controls the drum motor 171, the capstan motor 172, and the loading motor 173 through the drum servo 133, the capstan servo 134, and the loading motor driver 135. .

In this operation, the system control (microcomputer) 131 in the timer shecon servo unit 130 performs the steps shown in FIG. 4 if there is a key input for executing the tape recording mode following the loading operation by the tape cassette in. Will run.

That is, the step of executing the double recording prevention function in the initial recording part according to the present invention first determines whether the key input is the recording mode execution command when there is an external key input for the VSI operation following the cassette tape loading. .

In this case, when a command for recording is recognized by the microcomputer 131, the microcomputer first outputs the audio recording / reproducing unit so that a signal for video tape full erasing is output from the OSC 124 to the full width erasing head 176. 120) otherwise it will wait.

In this step, if there is a tape erase signal output, the microcomputer executes timing through a timer to determine whether the timing time T has reached the set time.

The set time is set to the time taken for the tape 260, which was in contact with the full width erasing head 176, to reach the video head 175 at the standard traveling speed of the tape.

On the other hand, when the timing time for delaying the video signal reaches the set time, the microcomputer 131 determines that the tape portion in contact with the video head 175 is completely completely erased, and operates the input selector by operating the delay unit 161. The video signal from 165 is transmitted to the video recording and reproducing unit 140.

Therefore, the video signal for recording on the video tape is recorded from the part where the previous video recording contents have been sufficiently erased by the full width erasing head, thereby preventing the occurrence of video recording redundancy in the recording start portion of the tape. .

As described above, when the other video signal is recorded on a video tape which has recorded the video signal more than once, the existing video signal and the new video signal are superimposed on the video recording start. This can be avoided.

Therefore, the present invention makes it possible to manufacture high quality VSAL which is free from screen blurring and noise generation at the boundary of the recording section during videotape playback.

Claims (2)

A video signal recording method in VSI, comprising: supplying an oscillation signal for erasing video and audio signals on a videotape to a full-width erasing head in accordance with VSI's video tape recording mode execution start; And supplying a video signal for recording to a video head installed on the head drum with a delay time after the oscillation signal is generated. 2. The method according to claim 1, wherein the delay time is determined by the time taken for the tape portion located in the full-width erasing head to reach the video head position on the rotating head drum at the running speed of the video tape.