JPS6374288A - Recording and reproducing device for video signal - Google Patents

Abstract

PURPOSE:To record and reproduce a monochroic picture with high resolution by providing a high pass filter, forming a transmission line a bypassing the high pass filter at recording/reproduction of a monochroic signal so as to cut off a color difference signal outputed from a color difference signal recording and reproducing system at the recording/reproduction of monochroic signal. CONSTITUTION:An output signal of a frequency correction circuit 16 is bypassed for the high pass filter 18 at the monochroic signal recording and outputted to a mixer 22 via a switch 20, the output of a low pass filter 26 and the input of the mixer 22 is connected to ground. Thus, signal components over all hands of a luminance signal are outputted to a magnetic head 32 and the picture with high resolution is recorded at the monochroic recording. At the reproduction of monochroic signal, the output signal of an amplifier 34 bypasses a high pass filter 36 and is outputted to a frequency correction circuit 40 via a switch 38. Thus, the signal component over the entire band of the luminance signal at the base band is outputted to an encoder 46 and the picture with high resolution is obtained at the reproduction of a monochroic signal.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a video signal recording and reproducing device, and more particularly to a video signal recording and reproducing device suitable for recording and reproducing monochrome and color video signals. BACKGROUND OF THE INVENTION Recently, it has been possible to electronically photograph a subject by combining an overimage device such as a solid-state image sensor or an image pickup tube with a recording device that uses a magnetic disk, which is inexpensive and has a relatively large storage capacity, as a recording medium. Electronic still camera systems have been developed that record still images on magnetic disks and reproduce the images using a separately provided television system, printer, or the like. In addition, there is a video magnetic recording system that captures still images recorded on visible recording media such as ordinary film and photographic paper and records them on a magnetic disk, and a video magnetic recording system that reads video signals from the magnetic disk and displays them on a television etc. In such a conventional magnetic recording and reproducing device where a video reproduction system has also been realized, a luminance signal recording system that FM modulates a luminance signal of the video signal into a predetermined frequency range;
It has a chroma signal recording system that FM modulates the color difference signal of the video signal to a predetermined frequency, and is configured to perform color recording of the video signal based on the signals obtained from these image recording systems. .

In this case, the luminance signal recording system includes a high-pass filter that passes signal components in a frequency range higher than the frequency where the frequency characteristics of the luminance signal and color difference signal intersect among the entire luminance signal band. During monochrome recording, the video signal is recorded based on the luminance signal extracted by the high-pass filter, and the output signal of the chroma signal recording system is cut off so that it is not recorded.

Therefore, the signal components of the luminance signal lower than the frequency at which the frequency characteristics of the luminance signal and color difference signal intersect are blocked, and phenomena such as chroma signal components being superimposed on the luminance signal occur, resulting in a high-resolution image. The problem was that I couldn't get it.

[Object of the invention] The present invention has been made in view of the above circumstances, and
It is an object of the present invention to provide a video signal recording and reproducing device capable of recording and reproducing monochrome images at high resolution.

[Existing requirements of the invention]

In order to achieve the above object, the present invention records a luminance signal and a color difference signal by FM modulating each at a predetermined frequency, or performs FM demodulation of a luminance signal and a color difference signal which have been FM modulated and recorded at a predetermined frequency. In a recording/reproduction device for a video signal to be reproduced, the luminance signal recording system or luminance signal reproduction system operates in a frequency range higher than the frequency near the intersection of the respective frequency characteristic curves of the luminance signal and the color difference signal among the entire band of the recorded signal. bypass means that includes a high-pass filter that passes a signal component and forms a transmission path that bypasses the high-pass filter during monochrome recording and playback; and a signal cutoff that blocks color difference signals output from the color difference signal recording and playback system during monochrome recording and playback. It is characterized by comprising means.

[Embodiments of the invention]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a video signal recording and reproducing apparatus according to the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 shows the configuration of an embodiment of a recording system of a video signal recording/reproducing apparatus according to the present invention. In the figure, a decoder 10 is connected to an FM modulator 12 of a 1-variant signal recording system and an FM modulator 14 of a chroma signal recording system.
2 is connected to a mixer 22 via a frequency correction circuit 16, a high-pass filter 18, and a switch 20.

On the other hand, the FM modulator 14 is connected to the mixer 22 via a frequency correction circuit 24, a low-pass filter 26, and a switch 28. The mixer 22 is connected to a magnetic head 32 via a recording amplifier 30.

A video signal containing a composite synchronization signal is supplied to the decoder 10, and this video signal is separated by the decoder 1o into a luminance signal containing the composite synchronization signal and color difference signals R-Y and B-Y. It is supplied to factory 4. The luminance signal including the composite synchronization signal is FM-modulated to the high frequency side by the FM modulator 12 and output to the high-pass filter 18 via the frequency correction circuit 16. The high-pass filter 18 is configured to pass a signal having a frequency at which the frequency characteristics of the luminance signal and the color difference signal intersect, for example, a signal of 2.5 MHz or more.
A signal of 5MH2 or more is sent to the mixer 22 via the switch 20.
supplied to

On the other hand, the color difference signals R-Y and B-Y are FM-modulated to the lower frequency side by the FM modulator 14 and output to the low-pass filter 26 via the frequency correction circuit 24. The low-pass filter 26 is configured to pass only signal components at frequencies below 2.5 MHz, for example, frequencies at which the frequency characteristics of the luminance signal and the color difference signal intersect, so that 2.5 MHz of the modulated video signal is passed during color recording. The following signals are output to mixer 22 via switch 28. The signal output from the luminance signal recording system and the signal output from the chroma signal recording system are mixed by a mixer 22 and output to an amplifier 30. This signal is amplified to a predetermined level and then supplied to the magnetic head 32, where it is magnetically recorded on a rotating recording medium such as a magnetic disk.

In this embodiment, in order to make the switch 20.28 function as a signal selection means, the contact 20b of the switch 20 is connected to the input side of the high-pass filter 18.
A contact 28b of the switch 28 is grounded. That is, when recording in monochrome, a signal transmission path that bypasses the high-pass filter 18 is formed in the luminance signal recording system by operating the switch 20.28, and a signal transmission path that blocks the output side of the low-pass filter 26 is formed in the chroma signal recording system. configured to form. Therefore, according to this embodiment, when recording in monochrome, the output signal of the frequency correction circuit 16 bypasses the high-pass filter 18 and is directly output to the mixer 22 via the switch 20, and the output side of the low-pass filter 26 is cut off. The input side of the mixer 22 is grounded.

As a result, no chroma signal is output to the magnetic head 32, and the entire brightness signal band (0 to 10 MHz) is output to the magnetic head 32.
The signal components covering the range are output to the magnetic head 32, and a high resolution image can be recorded during monochrome recording.

On the other hand, as shown in FIG. 2, the reproduction system includes a reproduction amplifier 34, a high-pass filter 36, a switch 38, a frequency correction circuit 40. FM demodulator 42, (No. 8 processing circuit 44,
Encoder 46, low pass filter 48, switch 50
, a frequency correction circuit 52, an FM demodulator 54, and a signal processing circuit 56.

The output signal of the magnetic head 32 is amplified to a predetermined level by an amplifier 34, and then output to a high-pass filter 36 included in the luminance signal reproduction system, and also to a low-pass filter 48 constituting the chroma signal reproduction system. Like the high-pass filter 18, the high-pass filter 36 is configured to pass a signal having a frequency at which the frequency characteristics of the luminance signal and the color difference signal intersect, for example, a signal of 2.5 MHz or more, and the reproduced signal obtained by the magnetic head 32. Of these, signal components of 2.5 MHz or higher are converted to FM via a high-pass filter 36, a switch 38, and a frequency correction circuit 40.
The signal is output to the demodulator 42. The FM demodulator 42 outputs a baseband luminance signal Y, and this signal is output to the encoder 46 via the signal processing circuit 44.

On the other hand, the low-pass filter 48 is configured to pass signal components of 2.5 MHz or less, and the regenerated F
Only signal components of 2.5 MHz or less of the M-state video signal are output to the FM demodulator 54 via the low-pass filter 48, switch 50, and frequency correction circuit 52. Then, the FM demodulator 54 outputs a baseband line-sequential color difference signal. This line-sequential color difference signal is synchronized by the signal processing circuit 56 and output to the encoder 46. The encoder 46 outputs a predetermined format (for example, NT
SC system) video signal is output.

This video signal is then output to a CRT control circuit and CRT, and an image is displayed on the screen of the CRT.

Here, in this embodiment, in order to make the switch 38.50 function as a signal selection means, the contact 38b of the switch 38 is connected to the input side of the high-pass filter 36.
A contact 50b of the switch 50 is grounded. Therefore, during monochrome reproduction, the output signal of the amplifier 34 bypasses the high-pass filter 36 and is directly output to the frequency correction circuit 40 via the switch 38, and the output of the chroma signal is blocked by the operation of the switch 50, and the frequency correction circuit The input side of 52 is grounded. Therefore, during monochrome playback, the entire baseband luminance signal band (0 to 10M
Hz) is output to the encoder 46, and the chroma signal is no longer output to the encoder 46. This makes it possible to obtain G1 high resolution images during monochrome playback.

Note that the switches 20, 28, 38, and 50 may each be configured by a mechanical switch or an analog switch.

〔Effect of the invention〕

As explained above, in the present invention, when recording in monochrome, the chroma signal is blocked and the signal components of the entire band of the luminance signal are used for recording. It is possible to obtain a monochrome reproduction image of

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of a recording system of a video signal recording/playback apparatus according to the present invention, and FIG. 2 is a block diagram of an embodiment of a playback system of a video signal recording/playback apparatus according to the present invention. It is. 12.14...FM modulator, 18.36...High pass filter, 20.28.38.50...Switch, 26.48...Low pass filter, 42
．． 54...FM demodulator.

Claims (1)

[Scope of Claims] A video signal in which a luminance signal and a color difference signal are each FM modulated at a predetermined frequency and recorded, or a luminance signal and a color difference signal which are each FM modulated and recorded at a predetermined frequency are FM demodulated and reproduced. In the recording and reproducing apparatus, the luminance signal recording system or the luminance signal reproducing system records signal components in a frequency range higher than the frequency where the respective frequency characteristic curves of the luminance signal and color difference signal intersect, out of the entire band of the recorded signal. A bypass means for forming a transmission path that includes a high-pass filter for passing through the high-pass filter and bypasses the high-pass filter during monochrome recording and reproduction, and a signal blocking means for blocking the color difference signal output from the color difference signal recording and reproduction system during monochrome recording and reproduction. A video signal recording and reproducing device characterized by: