JPH08275126A - Signal reproducing device - Google Patents

Abstract

PURPOSE: To avoid disturbance caused in a reproduced image of a video signal by keeping the operating state of a filter means when a synthesis means outputs a re-modulation auxiliary signal and excluding only the re-modulation auxiliary signal component included in a reproduced video signal. CONSTITUTION: A changeover means 4 gives a luminance signal 4a including a re-demodulation helper signal to an adder 5 when a control signal is at a high level. The adder 5 adds the signal 4a and a reproduced color signal 1b in a form of frequency multiplexing to generate and output a composite video signal 5a. The signal 5a is fed to a transmission line and to a filter means 6. The filter 6 is active only for a helper signal period and a composite video signal 6a not almost including the helper signal component included in the signal 5a is fed to an RF converter 7. The converter 7 applies trap processing to the received signal 6a and applies RF conversion to the result to provide an output of an RF signal. Thus, disturbance of the helper signal on a reproduced image of the video signal is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a signal reproducing apparatus which is compatible with a video signal of a predetermined broadcasting system and reproduces a series of high quality video signals having an aspect ratio different from that of the video signal. is there.

[0002]

2. Description of the Related Art FIG. 4 shows a VTR compatible with the PALplus system.
FIG. 5 is a diagram for explaining an RF converter, FIG. 5 is a diagram for explaining a trap process, and FIG. 7 is a diagram for explaining an ideal LPF characteristic. 8 and 9 are diagrams for explaining the characteristics of the LPF.

A high-definition video signal (EDTV; Extended Definition TV, high-resolution TV) that is compatible with the video signal of the current broadcasting system and improves the drawbacks of the current system.
There is PAL (Phase Alte
There is a so-called "PALplus" system which is intended to improve the image quality of the rnation by line (broadcast) system and to make it widescreen (an image having an aspect ratio of 16: 9).

As a system and a device relating to the PALplus system, a video signal recording / reproducing system, a video signal recording / reproducing device, and a video signal modulating / demodulating device (Japanese Patent Application No. 6-1601).
No. 2) was proposed. As described therein, the PALplus system video signal is generated in order to stretch a reduced widescreen original image while maintaining compatibility with a display device such as a TV receiver of the PAL broadcasting system which is a current broadcasting system. To improve the deterioration of vertical resolution,
A high-definition video signal (hereinafter referred to as "encoded video signal") on which an auxiliary signal (hereinafter also referred to as "helper signal") for superimposing the definition of video information, which is a main signal, is superimposed is transmitted. At the time of transmission, the helper signal is transmitted as a modulated helper signal that is AM-modulated at the color subcarrier frequency.

Since the signal reproducing apparatus compatible with the PALplus system is compatible with the current PAL system video signal and the PALplus system video signal, a recording medium (magnetic tape or the like) on which the signals of each system are recorded. ) Can reproduce the signal from.

As shown in FIG. 4, this signal reproducing apparatus is
Reproduced luminance signal 1 by reproducing the signal recorded on magnetic tape
a and VTR signal reproduction processing means 1 for demodulating the reproduction color signal 1b, and the auxiliary signal component contained in the reproduction luminance signal 1a obtained by the VTR signal reproduction processing means 1 is re-modulated to this auxiliary signal component in order to restore it to a predetermined mode. Remodulation processing means 2 for performing processing, and remodulation auxiliary signal 2 output by the remodulation processing means 2.
LPF (low-pass filter) 3 for removing unnecessary high-frequency components of a, remodulation auxiliary signal output from LPF 3, and VT
Reproduction luminance signal 1a output from the R signal reproduction processing means 1
And a switching means 4 for switching and outputting at a predetermined timing to output a luminance signal 4a in which an auxiliary signal component is combined, and the luminance signal 4a and the reproduced color signal 1b are added to perform a frequency-multiplexed composite video signal 5a. And an RF converter 7 for converting the composite video signal 5a into a radio frequency signal 7a.

At this time, the above-mentioned VTR signal reproduction processing means 1 has the same structure as the known VTR signal processing means,
Signal processing for reproducing and demodulating a signal magnetically recorded on a magnetic tape or the like to reproduce a video signal is performed. Although not described in detail here, it goes without saying that the reproduction signal reproduced from the VTR signal reproduction processing means 1 also includes an audio signal, and is reproduced by a signal processing means (not shown) of a system different from the video signal. Is played.

Further, the above-mentioned switching means 4 switches and connects the output terminals a and b on the basis of a control signal from a supply source (not shown) and outputs a signal supplied to each of them. For example, it is a signal for controlling the switching means 4 so as to selectively switch the output terminal a in the period in which the helper signal exists in the one field period of the above-mentioned encoded video signal and the output terminal b in the other periods.

By the way, when a video signal reproduced and output from a video signal reproducing device such as a VTR is displayed on a TV monitor or the like, a method for switching the input of the TV monitor and a channel dedicated to video are provided in the channels of the TV monitor. There is a way.

The input of the TV monitor is switched and displayed by switching the signal supplied from the dedicated input terminal. The method of providing the video dedicated channel is the above-mentioned radio frequency signal (for the TV monitor without the dedicated input terminal). "RF
(Also referred to as “signal”), the video signal converted to
The V monitor is provided with a dedicated reception channel for receiving this RF signal. Then, a video signal reproducing device such as a normal VTR has a dedicated output terminal for supplying a video / audio signal to be reproduced and output to the dedicated input terminal of the TV monitor, and a TV monitor having no dedicated input terminal. And an RF converter for supplying.

Now, in the RF signal, the above-mentioned current P
In the AL system, the audio signal in the RF signal is 5.5MHz
There is something to insert in. As shown in FIG. 5, this current P
In contrast to the AL system, the RF converter 7 described above has a frequency of 5.5 in the frequency band of the video signal by the trap means 7A before performing the RF modulation for the purpose of avoiding the interference between the video and the audio.
Attenuating the MHz band (see FIG. 6A for the gain characteristic,
(B) shows examples of group delay characteristics, respectively. The trapped video signal is supplied to the RF modulator 7B, modulated into a radio frequency signal by a carrier wave from a supply source (not shown), and output.

Here, the frequency band of the output signal of the VTR compatible with the current PAL system is within 5 MHz for the luminance signal and within 4.43 MHz ± 500 kHz for the chrominance signal, so that the above trap processing has no practical problem. .

On the other hand, the encoded video signal is the above-mentioned RF.
When converting and outputting to the RF signal by the converter 7, it is necessary to transmit all the video signals within the frequency band of about 5 MHz.
It must have the filter characteristics shown in. This is an LPF used for broadcasting equipment, etc.
The gain characteristic is symmetrical about 0.5 in the Hz band, and is a characteristic corresponding to the so-called VSB (Vestigal Side Band) transmission method (also referred to as VSB characteristic).

However, the LPF having such characteristics is expensive. Therefore, the LPF actually used in the above-mentioned VTR is, for example, as shown in FIG.
It has a VSB characteristic in which the gain characteristic is symmetrical about 0.5 in the band of about 3 MHz around 4.43 MHz. Both LPFs whose characteristics are shown in FIG. 7 and FIG.
Since the gain characteristic at 3 MHz is symmetrical about 0.5, there is no practical problem in the above VSB transmission system. That is, the video signal transmitted by this VSB transmission method can be demodulated by the video signal display means such as a TV receiver and a monitor.

[0015]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
As described in Japanese Patent No. 6012, the helper signal component output from the VTR signal reproduction processing means 1 is about 0 to 0.
Reproduction luminance signal 1 as a signal having a frequency band of 3 MHz
included in a. The helper signal modulated by the re-modulation means 2 has a carrier frequency of 4.43 MHz to + 3M.
A re-modulated helper signal 2a having an upper band of Hz and a lower band of -3 MHz is obtained, and the upper band is removed by the LPF 3 (VSB transmission method described above).
a is obtained (a waveform diagram of each of the helper signals 1a to 3a is omitted).

However, L having the characteristics shown in FIG.
When the composite video signal 5a obtained by using the PF as the LPF 3 is RF-modulated by the RF converter 7, the gain is attenuated in the band of 5.5 MHz by the track processing described above. Since the characteristics of No. 1 deteriorate significantly, and it does not function as a helper signal, there is a problem that the video signal is remarkably disturbed on the reproduction screen.

[0017]

In order to solve the above problems, the present invention provides a signal reproducing device having the following configuration.

The present invention is required to have an aspect ratio different from the aspect ratio of a predetermined broadcasting system, be compatible with at least the predetermined broadcasting system, and include at least a main signal containing video information and video additional information. A signal reproduction device for outputting a high-quality video signal composed of an auxiliary signal (helper signal) of a mode as a radio frequency signal, comprising: a signal reproduction processing means (VTR signal reproduction processing means 1) for reproducing a recorded signal. Re-modulation processing means for outputting a re-modulation auxiliary signal (re-modulation helper signal) obtained by re-modulating the auxiliary signal component contained in the reproduction signal obtained by the signal reproduction processing means into the required mode, Included in the replay video signal is a synthesizing means (switching means 4) for synthesizing the replay signal from the signal replay processing means and the remodulation auxiliary signal to output a replay video signal. Filter means (LPF6) for removing the re-modulation auxiliary signal component, and conversion means (RF converter 7) for converting the reproduction signal output from the filter means from which the re-modulation auxiliary signal component has been removed into a radio frequency signal. The present invention provides a signal reproducing apparatus, characterized in that the filter means is kept in an operating state when the synthesizing means outputs the re-modulation auxiliary signal.

[0019]

1 is a diagram for explaining a signal reproducing apparatus according to the present invention, FIG. 2 is a diagram for explaining a filter means which is an essential part of the present invention, and FIG. 3 is for explaining characteristics of the filter means. FIG. The signal reproducing apparatus according to the present invention will be described below with reference to the drawings. The same components as those described above are designated by the same reference numerals, and the description thereof will be omitted.

As shown in FIG. 1, the signal reproducing apparatus according to the present invention is constructed by adding filter means 6 to the signal reproducing apparatus described in the prior art. Reproduction luminance signal 1a output from the above VTR signal reproduction processing means 1
Is supplied to the remodulation processing means 2 and the output terminal b of the switching means 4 in the same manner as described above. The remodulation processing means 2 remodulates the helper signal contained in the reproduction luminance signal 1a, and the output terminal a of the switching means 4 is passed through the LPF 3 described above.
Is supplied to.

The switching means 4 switches and connects the output terminals a and b by the same control signal as described above,
For example, the re-modulated helper signal is output during the period (helper signal period) in which the helper signal exists in one field period, and the reproduction luminance signal 1a is output during the other periods. For example, the control signal becomes "H" during the period when the helper signal is present in one field period, and the output terminal a of the switching means 4
Switch and connect. During the other period, the control signal becomes "L", and the output terminal b of the switching means 4 is switched and connected. On the other hand, this control signal is also supplied to the filter means 6, and when the control signal is "H", the filter means 6 is operated, and when the control signal is "L", the operation of the filter means 6 is stopped.

When the control signal is "H", the switching means 4 supplies the luminance signal 4a including the re-demodulation helper signal to the adder 5 through the switching connection similar to that described above. The adder 5 adds the luminance signal 4a and the reproduction color signal 1b output from the VTR signal reproduction processing means 1 in the form of frequency multiplexing to generate and output a composite video signal 5a. The composite video signal 5a output from the adder 5 is supplied to a transmission line (not shown) and is also supplied to the filter means 6 which is an essential part of the present invention.

The filter means 6 is composed of, for example, a well-known filter circuit having a simple structure as shown in FIG. At this time, a coil L and a capacitor C are used so that the center frequency of the filter is 4.43 MHz (that is, the formula in the figure is satisfied), and the characteristics thereof are as shown in FIG.

At this time, when the composite video signal 5a is supplied to the above-mentioned filter circuit, the transistor Tr1 becomes conductive and the composite video signal component is supplied to the transistor Tr2. Since the control signal (“H”) described above causes the transistor Tr3 to conduct, a band (around the center frequency (4.43 MHz) determined by the coil L and the capacitor C of the composite video signal component supplied to the transistor Tr2 ( The frequency band of about ± 1.5 MHz) is attenuated. The attenuated composite video signal component is the transistor Tr2.
Is output as a composite video signal 6a.

When the control signal is "L", the switching means 4 is switched and connected to the output terminal b, and the transistor Tr3 of the filter means 6 becomes non-conductive. That is, the reproduction luminance signal 1a containing no helper signal component is frequency-multiplexed with the reproduction color signal 1b in the adder 5 and supplied to the filter means 6. However, since the transistor Tr3 is non-conductive, the transistor Tr1 outputs the signal. The composite video signal component is directly output from the transistor Tr2.

In this way, the filter means 6 supplies to the RF converter 7 the composite video signal 6a which is in the ON state only during the helper signal period and hardly transmits the helper signal (modulated helper signal) component contained in the composite video signal 5a. . The RF converter 7 can perform the above-described trap processing on the supplied composite video signal 6a, perform RF conversion, and output as an RF signal.

The composite video signal output as the RF signal is a signal which is a reproduction of an encoded video signal compatible with the PALplus system, but contains almost no helper signal component. That is, with this video signal, for example, the definition of the video information which is the main signal cannot be improved in a monitor or the like corresponding to the encoded video signal as described above, but the frequency component is not damaged even by RF modulation. Compared to the case of using a cost filter, a simple structure can prevent interference of a helper signal whose frequency component has been impaired on the playback screen of a video signal, and thus has a large practical effect.

Further, since the operation of the above-mentioned filter means 6 is controlled in accordance with the above-mentioned control signal, only the helper signal in the period of the helper signal has the frequency band removed by the filter means 6, and other There is no practical problem because the video signal during the period has no effect.

Of course, the above-mentioned filter means 6 is not limited to the above-mentioned configuration as long as it corresponds to one that removes the band corresponding to the frequency band of the helper signal included in the composite video signal 5a.

[0030]

As described above, according to the configuration of the present invention as set forth in claim 1, when the synthesizing means outputs the re-modulation auxiliary signal, it is included in the reproduced video signal by keeping the filter means in the operating state. Since it is possible to remove only the re-modulated auxiliary signal component that is generated, it is possible to prevent interference that has occurred on the playback screen of the video signal due to the frequency component of the helper signal being significantly impaired by RF modulation. The effect is that you can do it. Further, as compared with the case of using a high-performance filter that does not impair the frequency component of the helper signal even when performing the RF modulation, there is an effect that the above-mentioned interference can be prevented by an inexpensive and simple configuration.

[Brief description of drawings]

FIG. 1 is a diagram for explaining a signal reproducing device according to the present invention.

FIG. 2 is a diagram for explaining a filter means that is an essential part of the present invention.

FIG. 3 is a diagram for explaining characteristics of a filter means.

FIG. 4 is a diagram for explaining a signal reproducing device of a VTR compatible with the PALplus system.

FIG. 5 is a diagram for explaining an RF converter.

FIG. 6 is a diagram for explaining trap processing.

FIG. 7 is a diagram for explaining ideal characteristics of an LPF.

FIG. 8 is a diagram for explaining the characteristics of an LPF.

[Explanation of symbols]

 1 signal reproduction processing means 2 re-modulation processing means 4 combining means 6 filter means 7 conversion means

Claims (1)

[Claims] 1. A required aspect which has an aspect ratio different from an aspect ratio of a predetermined broadcasting system, is compatible with at least the predetermined broadcasting system, and includes at least a main signal containing video information and video additional information. A signal reproducing device for outputting a high-definition video signal composed of an auxiliary signal as a radio frequency signal, comprising a signal reproducing processing means for reproducing a recorded signal, and a reproduction signal obtained by the signal reproducing processing means. Re-modulation processing means for outputting a re-modulation auxiliary signal obtained by re-modulating the included auxiliary signal component in the required manner, a reproduction signal from the signal reproduction processing means, and the re-modulation auxiliary signal are combined. A synthesizing means for outputting a reproduced video signal; a filter means for removing the re-modulation auxiliary signal component contained in the reproduced video signal; and the re-modulation output by the filter means. A signal for converting the reproduction signal from which the auxiliary signal component has been removed into a radio frequency signal, and maintaining the filter means in an operating state when the synthesizing means outputs the remodulation auxiliary signal. Playback device.