JPS6012883A - High precision signal converting device of television signal - Google Patents

Abstract

PURPOSE:To obtain high precision TV picture while keeping perfect communication with present TV system by inserting high precision information into the gap of frequency band of current TV system in transmitting side and utilizing this inserted high precision information in receiving side. CONSTITUTION:High precision information YH1, YH2 of luminance signal Y is extracted by an HPF1 of transmitting side and modulated in cospifsct, cos2pifsct by modulators 4, 5. Each of modulated wave is added to BPF 2, 3, and frequency modulated signal components YH1', YH2' are taken out. After adding color difference signals C1, C2, said components are perpendicular two-phase modulated by modulators 6, 7 and added to luminance signal YL of subtracter 8 by an adder 11. The signal from transmitting side is separated into color signals by a Y/C separating circuit of receiving side and demodulated by synchronous detection circuits 13, 14. Pieces of high luminance information YH1', YH2' are taken out from the demodulated signal by HPF15, 16. Color signals C1, C2 are outputted from subtracters 19, 20 and processed by frequency conversion circuits 17, 18 and an adder 21, and high precision information is reproduced.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to improving the quality of television images, and in particular to a signal suitable for high-definition television images that is compatible with the current television system (NTSC system). This invention relates to a conversion device.

[Background of the invention]

In order to improve the image quality of the current television system, attempts have been made to display a display by doubling the scanning lines on the receiving side. This method achieves high image quality by eliminating image quality deterioration caused by interlace scanning, that is, interlace disturbance, and can improve vertical resolution.

However, since the characteristics of the horizontal resolution are determined by the standards of the current television system, there is a problem in that the characteristics cannot be improved with respect to the horizontal resolution.

[Purpose of the invention]

The purpose of the present invention is to insert high-definition information into the gap between the frequency bands of the current television system on the image sending side, and to utilize this inserted high-definition information on the receiving side, thereby completely matching the current television system. To provide a device capable of obtaining high-definition television images while maintaining communication performance.

[Summary of the invention]

In order to achieve the above object, the present invention multiplexes high-definition information into the gaps in the frequency spectrum of the current television system. This is intended to utilize a large amount of high-definition information.

[Embodiments of the invention]

The present invention will be described in detail below using the drawings.

FIGS. 1 and 2 show spectrum diagrams of current television signals for convenience of explanation of the following embodiment, and include a luminance signal Y and two color difference signals CI.

FIG. 1 shows how C2 is orthogonally modulated with the subcarrier fBc and nine color signals are multiplexed. To show these in more detail, as shown in FIG. 2, the spectrum of the color signal is interpolated between the valleys of the spectrum of the luminance signal.

FIG. 3 shows a frequency characteristic diagram when a high-frequency component of a luminance signal is used as high-definition information, in order to explain the operation of an embodiment of the signal conversion device according to the present invention.

FIG. 3(a) shows a luminance signal in a two-dimensional (horizontal-vertical) frequency display. The region Yt in the figure is the frequency region that can be displayed in the current television system.

On the other hand, MHI and YI (□ indicate high-definition information used in the present invention. These two high-definition information
Frequency conversion is performed to a signal in the region indicated by 2'. After adding the color difference signals Cx and C2, orthogonal 2
The luminance signal YL is phase-modulated and the orthogonal two-phase modulated signal is converted into a luminance signal YL.
is added to create a signal similar to the current television system.

FIG. 3(C) shows the frequency spectrum of this method.

In the figure, areas Yt, C1, and C2 have the same frequency characteristics τ as the current television system, and Ynt' and YR2' are newly inserted high-definition information. On the receiving side, after Y/C separation, the signals are demodulated by synchronous detection into C, Yi1', and C2 and Ya2' signals as shown in Figure 3(b), and the high-definition information YHI' and YH2' are removed. The signals are output and decoded by frequency inverse conversion as the original high-definition information YH1 and YFI2 as shown in FIG. 3(a). Therefore, according to the present invention, it is possible to improve the resolution in the horizontal direction by using the high-definition information of YHIT YI2.

If this signal is received by a current monitor on the receiver side, high-definition information YHI' and YH2' will appear as low-frequency components of the luminance signal, but the high-definition information has less power and There is little interference because the polarity is reversed every frame.

FIG. 4 shows a configuration diagram of the image sending side in an embodiment of the apparatus according to the present invention, in which high-definition information Ygt, YI2 of the luminance signal Y is extracted by a bypass filter (HPF) 1. cosπfsc t, co at modulator 4.5, respectively
It is modulated by s fCfsc L (fsc is the subcarrier frequency), frequency-converted by a bandpass filter (BPF) 2.3, and the signal components of 9Ynl' and YH2' are extracted, and color difference signals C1 and C2 are added to them. After addition by adders 9 and 10, modulators 6 and 7 add cos2πfsct.

modulated by sin 2πfact (i.e. orthogonal 2
After phase modulation), the adder 11 adds it to the luminance signal YL. Note that the luminance signal YL is obtained by subtracting the output of the HPF with a subtracter 8.

FIG. 5 shows an example of the configuration of the image receiving side. High-definition information YHI'HYa2' of the Y/C separation is extracted, and this signal is subtracted by subtractors 19 and 20 to obtain color difference signals Cr,
Demodulate Cz. On the other hand, Yt+1' and YH2' are converted into original frequency component signals by frequency conversion circuits 17 and 18, and added to YL by an adder 21, thereby reproducing high-definition signals Yal and YI2.

In general, there are various methods for inserting high-definition information in addition to this embodiment. FIG. 6 shows an embodiment of the invention with another insertion. In the current television system, the color signal is (525/4.-15
), and (-525/4°15). Therefore, (525/4.15), and (-
525/4. -15) Since there is a gap around the area, it is also possible to allocate high-definition information to this area. For this reason, high-definition information YH subjected to orthogonal two-phase modulation in this area
It is also possible to insert 1'&YnJ.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to efficiently insert high-definition information, and it is effective in improving the quality of television images while maintaining complete communication with the current system.

[Brief explanation of drawings]

Figures 1 and 2 are spectrum diagrams of current television signals, Figure 3 is a frequency component diagram for explaining the principle of the present invention, and Figures 4 and 5 are respectively transmission side diagrams in one embodiment of the present invention. and a block diagram of the receiving side, and FIG. 6 is a frequency component diagram for the purpose of explaining another embodiment of the present invention. 1.15.16...Bypass filter, 2,3...
Bandpass filter, 4, 5, 6.7...Modulator, 8
゜19.20...Subtractor, 9, 10, 11.21...
・Adder, 12...Y/C separation circuit, 13.14...
- Synchronous detection circuit, 17.18... Frequency conversion circuit. Agent Patent Attorney Akio Takahashi No. 12 Kaya 2 Fig. fs frt: ty@yt, @ Fig. 3 V (Phantom No. 4 ￥5 Fig.

Claims (1)

[Claims] 1. A high-definition signal conversion device for a television signal, comprising means for separating high-definition information and means for frequency conversion, and separating and frequency-converting the high-definition information, followed by orthogonal modulation and addition.