JP2845037B2 - Video signal processing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video signal processing apparatus for recording and reproducing a video signal called a wide television having an aspect ratio of 16: 9 on a disk or VTR.

[0002]

2. Description of the Related Art In recent years, standards for wide television have been proposed, and there has been an increasing demand for recording and reproducing apparatuses for wide television signals.

Hereinafter, a method of transmitting a video signal of a wide-screen television will be described with reference to FIG. (a) represents an original signal having an aspect ratio of 16: 9. In this example, the number of scanning lines is 576. Next, the number of scanning lines of the original signal is thinned out to 432, and a main signal (b) is obtained. At this time, the vertical high frequency band is lost due to the thinning, so at the same time as obtaining the main signal of (b), the high frequency band is extracted by the vertical filter and the vertical high frequency
As (c), transmission is performed by the remaining 144 scanning lines. And
As shown in (d), 77 vertical high frequency signals are arranged above and below the main signal and transmitted. If this signal is displayed on a conventional television having an aspect ratio of 4: 3, a vertical high-frequency signal can be received vertically, and a 16: 9 main signal can be received for the central 432 lines, which is compatible. In order to make the vertical high-frequency signal inconspicuous when displayed on a conventional television, the signal is transmitted as a signal (e) in which the amplitude around the black level is suppressed.

[0004]

However, if such a signal is recorded as it is on a conventional VTR or laser disk (LD), the S / N becomes low due to the low level of the vertical high-frequency signal, so that it cannot be used in a wide-screen television. Even if the vertical resolution is restored by restoring the vertical high-frequency signal, there is a disadvantage that it looks disturbing.

The present invention has been made to solve the above-mentioned conventional problems, and it is an object of the present invention to provide a video signal processing apparatus having a good S / N by appropriately changing a gain of a scanning line for transmitting a vertical high frequency signal. Aim.

Also, the present invention relates to a direct F
It is an object of the present invention to provide a video signal processing apparatus that can be used for both an apparatus that performs M modulation recording and an apparatus that performs low-frequency conversion recording of color signals such as a VTR.

[0007]

In order to achieve this object, a video signal processing apparatus according to the present invention is arranged so that n (n is an integer) scanning lines are thinned out to m (m is an integer), and The vertical high-frequency components lost by the transmission are transmitted by nm scanning lines, and the above-mentioned nm of the video signal having the aspect ratio of 16: 9 is transmitted.
A gain detecting circuit for detecting the gain of the scanning line period of the present, a first gain control circuit the gain of the scanning line period of the n-m present by said gain detecting circuit is controlled, the first gain control circuit An FM modulation circuit for FM modulating the output of the
Recording means for recording the output of the modulation circuit on a recording medium; reproduction means for reproducing the recording medium; FM demodulation circuit for FM demodulating the output of the reproduction means; and a burst signal of a video signal output from the FM demodulation circuit And a second gain control circuit for controlling the gain of the output of the FM demodulation circuit during the nm scanning lines with the output of the burst level detection circuit. I have.

[0008]

According to the present invention, a video signal with a good S / N can be obtained when the recorded / reproduced signal is restored on a wide-screen television to a vertical high-frequency signal to restore the vertical resolution.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a configuration of a video signal processing device according to a first embodiment of the present invention. In FIG. 1, an input video signal is input to a gain control circuit 11. The video signal is a wide television signal in which the above-described vertical high-frequency signal is inserted into scanning lines at the top and bottom of the screen. The gain of the vertical high-frequency signal of the video signal is detected by a gain detection circuit 10 and the gain control circuit 11 is controlled so that the gain becomes constant.
Control. Further, the timing generation circuit 12 generates the timing of the vertical high-frequency signal period, and supplies it to the gain detection circuit 10 and the gain control circuit 11. In this way, the video signal obtained at the output of the gain control circuit 11 maintains the gain of the vertical high-frequency signal at an optimum constant value. This video signal is FM-modulated by an FM modulation circuit 13 and recorded on a medium by a recording means 14.
In this embodiment, an LD is suitable as a recording medium because a signal is directly FM-modulated.

Next, the signal reproduced from the medium by the reproducing means 15 is FM-demodulated by the FM demodulation circuit 16. Since the signal is directly FM-modulated, the burst signal is also added to the scanning line through which the vertical high-frequency signal is transmitted. Therefore, if the burst level is detected by the burst level detection circuit 17, the gain appropriately changed by the gain control circuit 11 can be determined. Therefore, the gain of the vertical high-frequency signal can be restored by controlling the gain control circuit 18 with the output of the burst level detection circuit 17 so that the burst level becomes constant. The timing of the scanning line to which the vertical high-frequency signal is transmitted is generated by the timing generation circuit 19. In this way, the vertical high frequency signal can be recorded and reproduced at an optimum level,
The S / N of the vertical high frequency signal can be improved.

In the above description, the control of the gain has been described by the feedforward control from the gain detection circuit 10 to the gain control circuit 11, and the control from the burst level detection circuit 17 to the gain control circuit 18. However, the feedback control can also be realized. .

Next, a second embodiment of the present invention will be described with reference to FIG. The present embodiment is an example suitable for an apparatus for converting a color signal into a low-frequency band and recording the same, such as a home VTR. The input wide-screen television image signal is separated by a YC separation circuit 40 into a luminance signal and a chrominance signal. However, the line to which the vertical high frequency signal is transmitted is directly output to the luminance signal output. The gain of the vertical high frequency signal sent to the luminance signal output is detected by a gain detection circuit 41, and is controlled to an optimum level by a gain control circuit 42. The vertical high-frequency signal at the optimum level is finally FM-modulated by the FM modulation circuit 46 and recorded in the luminance signal channel. I can't go back. One method is to leave only the burst signal on the transmission line of the vertical high-frequency signal and control the gain based on the burst level during reproduction in the same manner as in the first embodiment to restore the original signal. This method is simple, but has a drawback that a high frequency burst cannot be recorded in a luminance signal channel in a VHS system VTR having a narrow transmission band. Therefore, in the present embodiment, the information on the gain change changed by the gain control circuit 42 is generated by the pilot signal generation circuit 44, and the switch circuit 45 is generated during the horizontal synchronization period.
The method of switching and adding is adopted. FIG. 3 shows an example of the addition method. FIG. 3 (a) is a vertical high frequency signal, and the signals to which the pilot signal is added are (b) and (c). (b)
Is for adding a DC value according to the gain, and (c) is for adding a burst signal having a relatively low frequency that can be recorded on a luminance signal channel.

In this manner, the video signal to which the pilot signal has been added is FM-modulated by the FM modulation circuit 46, and the color signal converted to the low band by the frequency conversion circuit 29 and the mixing means 4.
7 and are recorded on a recording medium by the recording means 48. Next, the video signal reproduced from the recording medium by the reproducing means 50 is separated into a luminance signal and a chrominance signal by the high-pass filter 51 and the low-pass filter 55, respectively. The luminance signal is F
FM demodulation is performed by an M demodulation circuit 52, a pilot signal is separated by a pilot signal separation circuit 53, and a gain is controlled by a gain control circuit 54 according to the level. as a result,
The vertical high frequency signal returns to the gain before recording. The line to which the vertical high-frequency signal is transmitted is designated by the timing generation circuit 57 to the gain control circuit 54. On the other hand, the chrominance signal is converted into a high frequency band by the frequency converter 56 in the opposite direction to that at the time of recording, mixed with the luminance signal by the mixing means 58, and output as a wide TV signal.

[0015]

As described above, according to the present invention, the vertical high frequency signal is controlled to the optimum level before recording and returned to the original level after reproduction, so that the vertical high frequency signal is transmitted to the VTR or LD by the S / S signal. There is an effect that recording and reproduction can be performed N times better.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a video signal processing device according to a first embodiment of the present invention.

FIG. 2 is a block diagram illustrating a configuration of a video signal processing device according to a second embodiment of the present invention.

FIG. 3 is a waveform diagram showing a waveform of a vertical high frequency signal to which a pilot signal is added according to the present invention.

FIG. 4 is a schematic diagram showing a method of transmitting a wide-screen television signal.

[Explanation of symbols]

 Reference Signs List 10 gain detection circuit 11, 18 gain control circuit 17 burst level detection circuit 44 pilot signal generation circuit 45 switch circuit 29, 56 frequency converter 53 pilot signal separation circuit 54 gain control circuit

Claims (2)

(57) [Claims] 1. A method in which n (n is an integer) scans are thinned out to m (m is an integer) scans, and vertical high frequency components lost by the thinning are transmitted by nm scan lines. A gain detection circuit for detecting a gain of the video signal having an aspect ratio of 16: 9 during the nm scanning lines, and a gain of the nm scanning line period is controlled by the gain detection circuit. First
And the output of the first gain control circuit is F
FM modulation circuit for performing M modulation, recording means for recording the output of the FM modulation circuit on a recording medium, reproduction means for reproducing the recording medium, and FM for demodulating the output of the reproduction means
A demodulation circuit; a burst level detection circuit for detecting a level of a burst signal of a video signal output from the FM demodulation circuit; and the nm scanning lines of the output of the FM demodulation circuit at the output of the burst level detection circuit. A video signal processing device comprising a second gain control circuit for controlling a gain in a period. 2. n (n is an integer) scanning lines are thinned out to m (m is an integer) lines, and vertical high frequency components lost by being thinned out are transmitted by nm scanning lines. A YC which separates a video signal having an aspect ratio of 16: 9 into color signals and luminance signals in the m scanning line periods in which the pixel signals are decimated, passes through the nm periods, and outputs to the luminance signal output. A separating circuit, and the n- output of the luminance signal output from the YC separating circuit.
a gain detecting circuit for detecting the gain of the scanning line period of the m, a first gain control circuit the gain of the scanning line period of the n-m present by said gain detecting circuit is controlled, the first gain control A gain information adding circuit for adding the gain information obtained by the circuit to the luminance signal; an FM modulation circuit for FM-modulating an output of the gain information adding circuit; and a frequency conversion of a color signal output of the YC separation circuit to a low band. A first frequency converter;
Recording means for adding the output of the M modulation circuit and the output of the first frequency converter and recording the result on a recording medium; reproducing means for reproducing from the medium; and an FM-modulated luminance signal and frequency of the output of the reproducing means A filter circuit for extracting the converted color signal, an FM demodulation circuit for FM demodulating a luminance signal output from the filter circuit, a second frequency converter for frequency-converting the color signal to a high frequency band, and an FM demodulation circuit. A video signal processing apparatus comprising: a second gain control circuit for controlling a gain in the nm scanning line periods according to output gain information.