JPS63250297A - Video signal recording/reproducing device - Google Patents

Abstract

PURPOSE:To improve picture quality by automatically separating a trap circuit for removing a chrominance subcarrier signal added to a Y signal system circuit from a circuit in a state where the signal of a Y/C input terminal is selected. CONSTITUTION:In case of introducing a luminance signal and a chrominance signal into a VTR by using the Y/C input terminal 20, the contacts of switching circuits 1A-1D are controlled so as to fall to lower sides. Then, the luminance signal is supplied to a luminance signal process circuit 9 through an amplifier 6, a delay circuit 7 and the trap circuit 8 and the chrominance signal is directly supplied to a chrominance signal process circuit 14 through a color process circuit 12. Thus, the luminance signal and the chrominance signal are supplied to the luminance signal process circuit 9 and the chrominance signal process circuit 14 without passing through a Y/C separation circuit 3 so as to reduce the deterioration of picture quality. Since the trap circuit 8 is excepted from the luminance signal system circuit by a switch circuit 1D, the high pass component of the luminance signal can be prevented from attenuating by the trap circuit 8 and by using the Y/C input terminal 20 the picture quality is improved and resolution is not damaged.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a video signal recording/reproducing device suitable for separating a video signal into a luminance signal component and a color signal component and recording it on a magnetic tape or the like. It is.

[Summary of the invention]

The video signal recording/reproducing apparatus of the present invention includes, for example, a video terminal for inputting a composite video signal, and a Y/C input terminal for inputting signals separated into a luminance signal and a color signal. When the Y/C input terminal signal is selected, the trap circuit for removing the color subcarrier signal added to the Y signal system circuit is automatically disconnected from the circuit to improve image quality. It is.

[Conventional technology]

A magnetic recording/reproducing device (VTR) capable of recording or reproducing a video signal generally separates a composite video signal into a luminance signal component and a color signal component.
The luminance signal component is frequency modulated (
(low carrier FM signal), the color signal component is converted to a low frequency, and the carrier frequency is used as a bias signal,
The information is recorded in a superimposed manner on tracks formed diagonally on the magnetic tape.

In this video signal recording/reproducing method, the color signal is converted to a low frequency band, so color unevenness is less likely to occur due to time axis fluctuations, and the luminance signal is FM modulated, so it is sufficiently stable against level fluctuations. Measures can be taken and waveform distortion is less likely to occur.

However, when outputting a composite TV signal from a TV tuner or the like and recording it on a VTR, it is first necessary to perform Y/C separation to extract color signal components from the input composite TV signal.
There is a problem in that the presence of the separation circuit degrades the quality of the luminance signal in particular.

Therefore, in the case of video signals output from television cameras, etc., which are not limited to composite video signals,
A VTR has been proposed that is configured so that a luminance signal and a color signal can be input through separate terminals, thereby making it possible to record on a magnetic tape without performing Y/C separation.

[Problem that the invention seeks to solve]

In this way, in addition to the conventional terminal for receiving composite video signals (video input terminal), there is also a terminal (Y
/C input terminal), when the luminance signal and color signal are separated as a video source, recording can be performed without going through the Y/C separation circuit by using the Y/C input terminal. image quality can be improved.

However, even with this method, there is a problem in that the trap for removing the color subcarrier frequency provided in the luminance signal system circuit attenuates the high frequency component of the luminance signal, limiting improvement in resolution.

[Means for solving problems]

The present invention has been made in view of these problems.
A switch circuit is provided that simultaneously excludes the color subcarrier trap circuit provided in the luminance signal system circuit when the Y/C input terminal is selected by the switch circuit.

[Effect]

When a luminance signal and a chrominance signal are input to the Y/C input terminal and are individually processed and recorded, the trap circuit that removes the chrominance subcarrier frequency (3,58MH2) from the luminance signal system circuit becomes inactive. Therefore, the VTR can perform recording/playback of higher image quality.

〔Example〕

FIG. 1 shows a video signal recording/reproducing apparatus according to the present invention.
In particular, it is a block diagram showing an embodiment of the recording system, where IO is a video input terminal, 20 is a Y/C input terminal into which luminance signal components and color signals can be input individually, 30 is a video output terminal, and 40 is a video input terminal. Similarly, it is a Y/C output terminal that can separately output a luminance signal component and a color signal component.

IA, IB, Ic, and ID indicate switch circuits that are configured to switch simultaneously. For example, when selecting a composite video signal from the video input terminal 10, each switch circuit 1 (A, B, C, D) is manually switched. ) will fall upward. Further, when the signal of the Y/C input terminal 20 is selected, the contact piece falls downward. (Incidentally, the switch circuit ID may have its contacts tilted downward during playback.) 2 is an AGC amplifier that adjusts the level of the input video signal so that the sync chip level is constant; 3 is a brightness signal Y/C separation circuit that extracts the color signal component from the components, 4
5 is a low-pass filter with an equalizer, and 5 is a comb-shaped filter for correcting the H level difference. Further, 6 and 7 are used to form a luminance signal corresponding to the time delay and level change of the luminance signal extracted by the low-pass filter 4 etc. from the Y/C separation circuit 3, which is usually composed of an IH play line. An amplifier (6dB) and a delay circuit (440nS) are shown.

8 shows a trap circuit for removing the color subcarrier frequency component (3.58 MHz) left behind in the separated luminance signal. is configured to work when 9 is a luminance signal processing circuit that performs signal processing necessary for supplying luminance signals to the recording head, and includes, for example, a clamp circuit, an emphasis circuit, a modulation circuit, etc.; 1;
Reference numeral 1 denotes an amplifier that outputs a luminance signal before modulation.

Reference numeral 12 denotes a color process circuit that performs level adjustment and frequency conversion of color signals, and includes, for example, an ACC circuit 12A, a converter 12B, a bandpass filter 12C, and the like. The signal converted into a low frequency converted color signal at a predetermined level is then supplied to the color signal processing circuit 14, where it is combined with the luminance signal converted into an FM signal by an adder circuit 25, and sent to the recording head via an amplifier 26. supplied to

A color signal (PB skewer C) reproduced from a circuit (not shown) is supplied to the color process circuit 12 consisting of an IC circuit during reproduction, and is output as a carrier color signal modulated at 3.58 MHz. , delay circuit 1
6.

Further, the reproduced luminance signal (FB@Y) is also supplied to the comb filter 5 from a circuit not shown, and outputted via the amplifier 11. Reference numerals 13A, 13B, and 13C indicate recording/reproducing mode changeover switches, which are controlled by control signals corresponding to the operation mode.

Switch circuit 1 for playback or recording (monitoring)
The luminance signals and color signals output from 3B and 13C are sent to switch 2 via lines L I + L 2, respectively.
3A, 23B, and further buffer amplifier 24A.
, 24B to the Y/C output terminal 40.

However, a composite video signal is formed by combining by the adder circuit 17, and the switches 18A and 18B
It is also possible to output the video to the video output terminal 30 via the video output terminal 30.

In this case, when the contact piece of the switch 18A is pushed downward, a composite television signal (E/E) outputted from a TV tuner in the VTR, for example, is selected.

Further, when the contact piece of the switch 18B is pushed down, the composite television signal is outputted via the digital signal processing circuit 19.

The digital signal processing circuit 19 includes an A/D converter, a field memory, a D/A converter, a control CPU, etc., and can digitally process video signals and skew correction during variable speed playback, for example. It is made possible.

Further, the output of the switch circuit 18B is configured to be input to the Y/C separation circuit 21, so that the signal processed by the digital signal processing circuit 19 can be separated into a luminance signal and a color signal again. . The separated luminance signal is then supplied to one terminal of the above-mentioned switches 23A and 23B via amplifiers (6 dB) 22A and 22B, and then to the Y/C output terminal 40.

Since the video signal recording/reproducing apparatus of the present invention has the above-described configuration, when a composite video signal is connected to the video input terminal 10, the switch circuit IA
By turning the contacts of , IB, IC, and 10 upward, the separated luminance signal is transferred to the Y/C branch circuit 3 as seen in the recording system circuit of a conventional VTR.
The color signal is supplied to the color signal processing circuit 14 via the color processing circuit 12, and the low frequency converted color signal is superimposed on the low carrier FM luminance signal and recorded on the magnetic tape.

In this case, by operating the trap circuit 8 that removes the color subcarrier frequency, the color subcarrier signal (3.58 MHz) remaining in the luminance signal is removed, so the remaining color is removed. Beat interference between the subcarrier signal and the carrier frequency of the FM signal (this beat interference tends to appear as a tree ring pattern on the screen) can be completely removed.

Further, when the luminance signal and the color signal can be input separately as in a video camera, the Y/C input terminal 20 is used to introduce the luminance signal and the color signal into the VTR.

In this case, switch circuits IA, IB, IC.

Control the ID contacts so that they fall down. Then, the luminance signal is sent to the amplifier (6dB)6. The color signal is supplied to the luminance signal processing circuit 9 via the delay circuit 7 and the trap circuit 8, and the color signal is directly supplied to the color signal processing circuit 14 via the color processing circuit 12.

Therefore, the luminance signal and the chrominance signal are supplied to the luminance signal processing circuit 9 and the chrominance signal processing circuit 14 without passing through the Y/C separation circuit 3, thereby reducing deterioration in image quality.

Furthermore, since the trap circuit 8 is excluded from the luminance signal system circuit by the switch circuit ID, which is a feature of the present invention, the high frequency component of the luminance signal is attenuated by the trap circuit 8 as shown by the dotted line in FIG. can be prevented,
By using the Y/C input terminal 10, the resolution is improved and the resolution is not compromised.

Note that by selecting the lower contact point by the switch circuit tC, the luminance signal component is transmitted to the amplifier 6 and the delay circuit 7.
will pass through. Then, it is converted into a signal having the same phase and level as the luminance signal when Y/C separated, thereby maintaining compatibility.

〔Effect of the invention〕

As explained above, the video signal recording/reproducing device of the present invention includes a video terminal for inputting a composite video signal,
In a device equipped with a Y/C input terminal, which is a terminal for inputting a video signal separated into a luminance signal and a color signal,
When you select to record the signal from the /C input terminal,
Since the color subcarrier signal trap circuit provided in the luminance signal system circuit is controlled to be excluded, the effect of preventing the recorded image from deteriorating, which is improved by the Y/C separation input, is achieved. be.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a recording system of a VTR showing an embodiment of the present invention, and FIG. 2 is a frequency characteristic diagram showing the operation of a trap circuit. In the figure, 10 is a video input terminal, 20 is a Y/C input terminal,
IA, IB, IC, 10 are switch circuits, 3 is a Y/C separation circuit, and 8 is a trap circuit.

Claims (1)

[Claims] In a video signal recording/reproducing apparatus equipped with a composite input terminal, a Y/C input terminal, and a switch circuit for selecting both of the input terminals, when the Y/C input terminal is selected, a color subcarrier signal trap is used. A video signal recording/reproducing device characterized in that the circuit is configured to be excluded from a luminance signal system circuit.