KR100322604B1 - Apparatus for controlling a level of recording color signal and video copy apparatus using thereof - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video recording apparatus, and more particularly, to a color level so as to maintain an optimal state regardless of the state of an input level of a color signal to be recorded in a D / DECK Dual Record Video Cassette Recorder (VCR) that performs FM recording. The present invention relates to a recording color level control device for controlling the control and a video copying device using the same.

According to the present invention, by controlling the color level to maintain the optimal level regardless of the level difference of the color signal recorded on the recording medium to be copied, it is possible to prevent deterioration of image quality due to the color signal during tape copying. It works. In particular, since a dropout may occur or a sudden change in color level may be prevented even in a horizontal synchronization signal section or a vertical equalization pulse section, color quality deterioration due to dropout may be prevented during FM COPY.

Description

Apparatus for controlling a level of recording color signal and video copy apparatus using Technical Field

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video recording apparatus, and more particularly, to a color level so as to maintain an optimal state regardless of the state of an input level of a color signal to be recorded in a D / DECK Dual Record Video Cassette Recorder (VCR) that performs FM recording. The present invention relates to a recording color level control device for controlling the control and a video copying device using the same.

In general, in the case of copying a video tape using a D / DECK VCR, there are two methods for recording a video signal.

The first video tape copy method is as follows.

As shown in FIG. 1, the modulated video signal detected by the video head 101 of the deck DECK1 to be reproduced is applied to the preamplifier 103 via the rotary transformer 102 and amplified with a constant gain. The signal amplified by the preamplifier 103 separates the luminance signal and the color signal modulated by the low pass filter LPF1: 104 and the high pass filter HPF1: 105, and the separated color signal is a frequency converter 106. Is converted to a high frequency before recording, and the separated luminance signal is subjected to frequency demodulation by the demodulation unit 108 after improving the frequency characteristic by the reproduction equalizer 107 composed of the picking circuit and the filter circuit. Then, the luminance signal and the color signal demodulated by the mixing unit 109 are synthesized.

In other words, the mixing unit 109 outputs the reproduced and demodulated video signal. The recording deck DECK2 of the dual-deck VCR inputs the reproduced and demodulated video signal from the reproduction deck DECK1 to generate a low pass filter LPF2: After separating the luminance signal and the color signal demodulated by the 110 and the high pass filter (HPF2: 111), the separated luminance signal is frequency-modulated by the FM modulator 112. The color signal output from the high pass filter HPF2 111 is converted into a low frequency by the frequency low pass converter 113.

Then, the luminance signal modulated by the FM modulator 112 by the mixing unit 114 and the color signal low-converted by the low frequency converter 113 are mixed, and the mixed modulated video signal is transmitted to the recording amplifier 115. After amplification, the tape is recorded by the video head 117 of the deck 2 via the rotary transformer 116.

The second video tape copy method is as follows.

As shown in FIG. 2, the modulated video signal detected by the video head 201 of the deck DECK1 to be reproduced is applied to the preamplifier 203 via the rotary transformer 202 and amplified with a constant gain. The signal amplified by the preamplifier 203 is separated into a luminance signal and a color signal modulated by the low pass filter (LPF) 204 and the high pass filter (HPF) 205. The low pass color signal that has passed through the low pass filter (LPF) 204 is amplified with a constant gain by the amplifier 206. The modulated luminance signal passing through the high pass filter (HPF) 205 is applied to the recording equalizer 208 again after the frequency characteristic is improved by the reproduction equalizer 207 composed of the picking circuit and the filter circuit. The waveform is shaped to have a frequency characteristic suitable for the recorder.

Then, the mixing unit 209 mixes the modulated luminance signal output from the recording equalizer 208 and the low-pass converted color signal output from the amplifier 206, and the mixed modulated video signal is written to the recording amplifier 210. After being amplified by), it is recorded on the tape by the video head 212 of the deck 2 via the rotary transformer 211.

The first recording method described above is the same as the general method of copying a video tape using two VCRs. On the other hand, since the second recording method processes and records the signal in a directly modulated state without demodulating the reproduced video signal, the signal processing is simple and the noise and frequency characteristics are improved compared to the first recording method. .

In FM COPY corresponding to the second recording method described above, in order to record a low-converted color signal separated from a modulated video signal reproduced from the video head of the playback deck to the recording deck, it is necessary to constantly control the color signal level. . If the recording level of the color signal is lower than the rated level, the S / N ratio of the color signal is lowered. If the recording signal is high, the image quality of the luminance signal is deteriorated, and a bit is generated on the screen by affecting the luminance signal.

According to the related art, in order to control the level of the color signal, the input color signal is simply amplified using an amplifier having a constant gain. By the way, the level of the modulated color signal reproduced in the reproduction deck is usually different depending on the recording state of the tape.

For this reason, in FM COPY according to the prior art, there is a problem in that the recording quality of the tape to be copied is deteriorated because the optimal color signal level cannot be controlled according to the recording state of the tape.

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a recording color level control device and a video copy device using the same to control the color level so as to maintain an optimal state regardless of an input state of a color signal to be recorded. It is.

1 is a block diagram of a video copying apparatus using a modulation and demodulation method in a dual deck VCR according to the related art.

2 is a block diagram of a video copying apparatus using the FM copying method in a dual deck VCR according to the related art.

3 is a block diagram of a video copying apparatus to which the present invention is applied.

Fig. 4 shows the level of the input / output signal of the recording color level control device according to the present invention.

In order to achieve the above technical problem, an apparatus for controlling a recording color level according to the present invention is a device for controlling a level of a low-conversion recording color signal, wherein the recording color signal is input to a gain corresponding to a gain control signal fed back. A gain control amplifier for amplifying the recording color signal, a level detector for inputting an output signal of the gain control amplifier, detecting a peak level of the input signal at predetermined intervals, and an output of the level detector for inputting a predetermined set level The following signals are cut off and the predetermined level value is output. Otherwise, a clipping unit for conducting an input signal and an output signal of the clipping unit are input, and compared with the predetermined reference voltage. Generate a gain control signal corresponding to the difference in voltage of the output signal of the clipping unit. Comparative characterized in that it comprises parts.

In order to achieve the above technical problem, a video copying apparatus according to the present invention uses a modulated luminance signal and a modulated color signal which are reproduced and separated from a reproduced deck VCR of a dual deck VCR (playback deck VCR, record deck VCR). A video copying apparatus, comprising: a gain control amplifier for inputting the modulated color signal, amplifying the modulated color signal with a gain corresponding to a feedback control signal fed back, and an output signal of the gain control amplifier; A level detector for detecting a peak level of the input signal at a period of time; and an output of the level detector, inputs a signal below a predetermined set level and outputs the predetermined set level value; otherwise, the input signal is conducted. A clipping unit to input the output signal of the clipping unit and compare it with a predetermined reference voltage A comparison unit for generating a gain control signal corresponding to a difference between the predetermined reference voltage and the voltage of the output signal of the clipping unit, and mixing and recording a modulation color signal amplified and output from the gain control amplifier unit and the modulation luminance signal And a mixing unit for generating a video signal, a recording amplifier for amplifying the recording video signal to a predetermined recording level, and recording means for recording the recording amplifier output signal on a predetermined recording medium.

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

As shown in FIG. 3, the video copying apparatus to which the recording color level control apparatus according to the present invention is applied includes a first video head 301, a first rotary transformer 302, a preamplifier 303, and an FM automatic gain adjusting unit ( FM AGC: 304, playback equalizer (PB EQ: 305), limiter 306, record equalizer (REC EQ: 307), drop out compensation (DOC: 308), low pass filter (LPF: 320), Color Killer 309, Gain Control Amplifier (GCA: 310), Level Detector (311), Horizontal Sync Signal Masking (H-Sync MASK: 312), Vertical Equalization Pulse Masking (V-EQ MASK: 313) And a clipping unit 314, a comparator (COMP: 315), a mixing unit (Y / C MIX: 316), a recording amplifier 317, a second rotary transformer 318, and a second video head 319. .

Here, the recording color level control apparatus 1000 according to the present invention includes a gain control amplifier (GCA) 310, a level detector 311, a horizontal sync signal masking unit (H-Sync MASK: 312), and a vertical equalization pulse masking. And a part (V-EQ MASK: 313), a clipping part 314, and a comparator (COMP: 315).

The second rotary transformer 318 and the second video head 319 of the recording deck DECK2 VCR correspond to recording means mounted to the drum assembly.

First, the operation of the deck DECK1 to be played is explained as follows.

The modulated video signal detected by the video head 301 of the deck DECK1 to be reproduced is applied to the preamplifier 303 via the rotary transformer 302 and amplified with a constant gain. Then, the modulated video signal inputted by the FM automatic gain adjusting unit (FM AGC) 304 automatically controls the gain to be output at a constant level. Of the signals output from the FM automatic gain control unit FM AGC 304, only the low-frequency converted color signals having a low frequency band are passed by the low pass filter LPF 320, and the frequency-modulated luminance signals are blocked. The low-converted color signal determines the phase and level of the burst by the color killer 309, and passes the low-converted color signal which is input when it is normal. Otherwise, when the phase of the burst is abnormal or the level is too small. In this case, the low-pass color signal is blocked.

The low frequency converted color signal output from the color killer unit 309 is applied to the recording color level control apparatus 1000 according to the present invention.

Next, the operation of the recording color level control apparatus 1000 will be described in detail.

The gain control amplifier (GCA) 310 inputs a signal output from the color killer 309 and amplifies the input signal with a gain value corresponding to the gain control signal applied from the comparator 315. The gain control signal is generated by the following operation.

In other words, the level detector 311 detects and outputs the peak level of the output signal output from the gain control amplifier GCA 310. Peak level detection can be performed, for example, in a period of 1H (one horizontal synchronization signal).

At this time, the horizontal synchronizing signal masking unit 312 generates a horizontal synchronizing signal masking pulse to prevent level detection in the generating section of the horizontal synchronizing signal, and the vertical equalization pulse masking unit 313 is level in the vertical equalizing pulse generation section. Vertical equalization masking pulses are generated to prevent detection.

When the horizontal synchronizing signal masking pulse and the vertical equalization masking pulse are applied to the level detector 311, the peak level detected in the previous horizontal line is held as it is without detecting the peak level in the section in which the masking pulse is generated.

The clipping unit 314 inputs the peak level detected by the level detector 311 to block a signal below the set reference level and to clip the output to the set reference level, otherwise to conduct the input signal. This is to prevent over-emphasis when dropout occurs or when the level of the modulated color signal changes abruptly.

The comparator 315 inputs an output signal of the clipping unit 314 to generate a gain control signal corresponding to the level difference between the reference voltage and the input signal compared to the set reference voltage. That is, the gain control signal is a value proportional to the level difference between the reference voltage and the input signal.

The gain control signal generated by the comparator 315 is fed back to the gain control amplifier 310 to determine the gain value.

Accordingly, the level of the low frequency converted color signal output from the gain control amplifier 310 is controlled constantly.

That is, as shown in Fig. 4, when the level of the low-frequency converted color signal input to the recording color level control device 1000 changes like T1 to T4, the output is controlled at a constant level in the T1 to T4 section. .

The signal output from the FM automatic gain adjusting unit 304 is also applied to a reproducing equalizer 305 composed of a picking circuit and a filter circuit to separate only the luminance signal frequency-modulated by the built-in filter circuit and then change the frequency characteristic. Improve. Then, the limiter LIMITER 306 limits the signal output from the reproduction equalizer 305 at a predetermined level in order to prevent black and white reversal.

The limited modulated luminance signal is waveform equalized by the recording equalizer (REC EQ) 307 to suit the characteristics of the recorder. The signal output from the recording equalizer (REC EQ) 307 is dropped by a dropout compensation unit (DOC) 308 composed of a switching circuit and a 1H delay line to switch and output a 1H delayed signal when a dropout occurs. To compensate out.

In addition, the dropout generation signal generated by the dropout compensation unit 308 when the dropout occurs is applied to the color killer unit 309. When the dropout generation signal is applied to the color killer 309, the color killer is operated to block the output of the color signal. This is to prevent the mixing of noise in the section where the dropout occurs.

The modulated luminance signal output from the drop-out compensation unit 308 and the low-frequency converted color signal output from the gain control amplifier 310 of the recording color level control device 1000 are mixed in the mixing unit 316. Then, the mixed modulated video signal output from the mixing unit 316 is amplified by the recording amplifier 317 to suit the characteristics of the recording system, and then, via the rotary transformer 318, to the video head 319 of the deck 2. Is recorded on the tape.

In such a case, when FM COPY is executed by the dual deck VCR, the level of the low-converted color signal reproduced from the reproduction deck can be controlled at a constant level to be recorded on the recording deck. In particular, it is possible to prevent a sudden change in the level of the low-conversion color signal in the drop out or in the horizontal synchronization signal section or the vertical equalization pulse section.

As described above, according to the present invention, the color level is controlled to maintain the optimal level regardless of the level difference between the color signals recorded on the recording medium to be copied, thereby degrading the image quality due to the color signals during tape copying. There is an effect that can be prevented. In particular, since a dropout may occur or a sudden change in color level may be prevented even in a horizontal synchronization signal section or a vertical equalization pulse section, color quality deterioration due to dropout may be prevented during FM COPY.

Claims (10)

An apparatus for controlling the level of a low-conversion recorded color signal, A gain control amplifier for inputting the recording color signal and amplifying the recording color signal with a gain corresponding to a feedback control signal fed back; A level detector which inputs an output signal of the gain control amplifier and detects a peak level of the input signal at a predetermined period; A clipping unit which inputs the output of the level detector to block a signal below a predetermined set level and outputs the predetermined set level value; And And a comparator for inputting an output signal of the clipping unit to generate a gain control signal corresponding to a difference between the predetermined reference voltage and the voltage of the output signal of the clipping unit in comparison with a predetermined reference voltage. Level control device. The recording color level control apparatus according to claim 1, wherein a predetermined period of the level detection unit is set to one horizontal driving section. The recording color level control apparatus according to claim 1, wherein the level detector is controlled so as not to execute peak detection in a horizontal synchronization signal generation section. 2. The recording color level control apparatus according to claim 1, wherein the level detector controls to hold and output the peak value in the previous horizontal line so as not to execute peak detection in the vertical equalization pulse generation section. A video copy apparatus for copying a video signal using a modulated luminance signal and a modulated color signal reproduced and separated by a reproduced deck VCR of a dual deck VCR (playback deck VCR, recording deck VCR), A gain control amplifier configured to input the modulated color signal and amplify the modulated color signal with a gain corresponding to a feedback control signal fed back; A level detector which inputs an output signal of the gain control amplifier and detects a peak level of the input signal at a predetermined period; A clipping unit which inputs the output of the level detector to block a signal below a predetermined set level and outputs the predetermined set level value; A comparison unit configured to input an output signal of the clipping unit to generate a gain control signal corresponding to a difference between the predetermined reference voltage and a voltage of the output signal of the clipping unit by comparing with a predetermined reference voltage; A mixing unit for mixing the modulated color signal amplified by the gain control amplifier and the modulated luminance signal to generate a recorded video signal; A recording amplifier for amplifying the recording video signal to a predetermined recording level; And And recording means for recording the recording amplifier output signal on a predetermined recording medium. 6. The video copying apparatus according to claim 5, wherein the predetermined period of the level detector is set to one horizontal driving section. 6. The video copying apparatus according to claim 5, wherein the level detector is controlled so as not to perform peak detection in the horizontal synchronization signal generation section. 6. The video copying apparatus according to claim 5, wherein the level detector controls to hold and output the peak value in the previous horizontal line so as not to perform the peak detection in the vertical equalization pulse generation section. A video copy apparatus for copying a video signal using a modulated luminance signal and a modulated color signal reproduced and separated by a reproduced deck VCR of a dual deck VCR (playback deck VCR, recording deck VCR), A color killer unit which inputs the modulated color signal to determine a burst phase and level of the modulated color signal and blocks the block if it is out of a predetermined range; otherwise, outputs the modulated color signal; A gain control amplifier configured to input the modulated color signal output from the color killer and to amplify the modulated color signal with a gain corresponding to a gain control signal fed back; A level detector which inputs an output signal of the gain control amplifier and detects a peak level of the input signal at a predetermined period; A clipping unit which inputs the output of the level detector to block a signal below a predetermined set level and outputs the predetermined set level value; A comparison unit configured to input an output signal of the clipping unit to generate a gain control signal corresponding to a difference between the predetermined reference voltage and the voltage of the output signal of the clipping unit by comparing with a predetermined reference voltage; A mixing unit for mixing the modulated color signal amplified by the gain control amplifier and the modulated luminance signal to generate a recorded video signal; A recording amplifier for amplifying the recording video signal to a predetermined recording level; And And recording means for recording the recording amplifier output signal on a predetermined recording medium. 10. The video copying apparatus of claim 9, wherein the color killer controls to block the output of the modulated color signal during a dropout period of the modulated luminance signal.