JPS62173885A - Device for generating high precision signal from television signal - Google Patents

Abstract

PURPOSE:To reduce interference given to an existing television receiver by dividing a high frequency component included in a luminance signal into two frequency bands, converting them into low frequencies, then adding one to a high frequency included in a signal Q and the other to that included in a signal I whose frequency band is limited. CONSTITUTION:A luminance signal YL with a wide frequency band the same as a luminance signal included in a signal NTSC and high frequency components YH1 and YH2 is separated from the high frequency band luminance signal Y by high-pass filters 22 and 24 and subtractors 21 and 23. The component YH1 is multiplied by a subcarrier (frequency fSC) by a multiplier 31, and passed through a band-pass filter 32, whereby it is shifted to a low frequency band by the fSC. The component YH2 is shifted to a low frequency band by 1.25 fSC in the same manner. The frequency- shifted signals YH2' and YH1' are added to the signal I with a limited frequency band by adders 5 and 6. After a modulator 9 applies perpendicular double phase modulation to the outputs of the adders 5 and 6 with the aid of a subcarrier, an adder 11 adds them to the signal YL. Accordingly the components YH1' and YH2' never overlap with a low frequency included in the luminance signal, thereby reducing the interference given to an existing receiver.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to improving the quality of television images, and relates to a high-definition signal generation device for television signals compatible with the current NTSC television system.

BACKGROUND OF THE INVENTION In recent years, many technologies have been developed to improve the image quality of television receivers. From high-definition television, whose horizontal image frequency and number of scanning lines are completely incompatible with the current NTSC television system, to 2 scanning lines on the receiver side under the current broadcasting system.
Various proposals have been made, including methods of doubling and interpolating for display. In the latter method, high image quality is achieved by removing image quality deterioration 1 caused by interlace scanning, that is, interlace disturbance, and it is possible to improve the resolution in the vertical direction. - As a method to improve the resolution in the horizontal direction, there is a method of multiplexing a high-frequency luminance signal into the gap between the color difference signal and the conventional luminance signal (Special Publication No. 69-
171387) and a method in which the color difference signal is added to the high frequency range and then modulated (Japanese Patent Publication No. 12883/1983 and Japanese Patent Publication No. 32493/1982). Also horizontal.

A new system that improves both vertical resolution and is compatible with the current NTSC television system is disclosed, for example, in the January 1985 issue of the Journal of the Society of Television Engineers, pages 886 to 897.

The apparatus for improving the above-mentioned horizontal resolution will be described below with reference to one drawing.

FIG. 3 shows a block diagram of a conventional high-definition signal generating device for television signals, and FIG. 4 shows a block diagram of a corresponding high-definition signal receiving device. Further, FIG. 6 shows a frequency characteristic diagram when a high frequency component of a luminance signal is used as high-definition information to explain a conventional example. In FIG. 6, a indicates a luminance signal in frequency display. YL in the figure is the frequency range that can be transmitted using the current television system. On the other hand, Y[1”112
indicates high-definition information used in the conventional example. These two pieces of high-definition information are obtained by frequency conversion operation as shown in Fig. 6, Y'I! + "II 2 The frequency is converted into a signal in the area indicated by 2. Then, one color difference signal C1,
After adding C2, orthogonal two-phase modulation is performed using the color subcarrier,
A luminance signal Y is added to this orthogonal two-phase modulated signal to produce a signal similar to that of the current television system.

Figure 5d shows the frequency spectrum of this method.

In the figure, the areas yL, c, , C2 have the same frequency characteristics as the current television system, and y/□+, Y'[2 is newly inserted high-definition information.

FIG. 3 shows a conventional transmitting device, in which a bypass filter 1 provides high-definition information Y)Il, YH of the luminance signal Y.
Extract 2. cosπfSc in each modulator 4.5
t (f, . is the subcarrier frequency) and frequency-converted by bandpass filter 2.3 "Hj '")!
Take out the signal component of 2 and add it to the color difference signal C, .
After adding C, , with adder 9.10, 00 with modulator 6°7
82πfsCt and 5in2πfsct (that is, orthogonal two-phase modulation), the 1 adder 11 outputs the luminance signal Y1. Add to. Note that the brightness signal YL is 1HPF.
is obtained by subtracting the output of .

FIG. 4 shows a conventional high-definition signal receiving device, in which a luminance/chrominance signal separation circuit 12 separates the chrominance signal, and synchronous detection circuits 13, 14, C4 and Y'□4, respectively.
Demodulates into C2 and "H2" signals.

High-definition information Y'M + with HPF15.16
``''H2 is taken out and this signal is subtracted by subtracters 19 and 20 to demodulate the color difference signal C4''2. On the other hand, 1Y
'□j'"H2 is converted into a single frequency component signal by the frequency conversion circuits 17 and 18, and added to YL by the adder 21, thereby generating a wideband luminance signal containing the high-definition signal YHj'YH2. Reproduce.

Problems to be Solved by the Invention However, in the configuration of the conventional example, when this signal is received by a current television receiver on the receiving side, the high definition information "Hj l Y'H2 is a low frequency component of the luminance signal. The problem is that the hailstones form an obstruction, resulting in images that are extremely difficult to view.

SUMMARY OF THE INVENTION In view of the above-mentioned problems, the present invention provides a device that maintains compatibility with the current television system as much as possible, eliminates the above-mentioned interference as much as possible, and can generate high-definition information.

Means for Solving the Problems To achieve this object, the high-definition signal generator of the present invention generates a high-definition signal YH2 from about 4.2 MHz to about 6.2 MHz, from about 1 o, a MHz to about A circuit that converts the frequency to 1.8MH2 and approximately 5.2MB2 to a,2
A circuit that converts the frequency of the high-definition signal YMl up to MHz from about 0.7 MH2 to about 1.7 MH2, and a circuit that removes the band from 0.5 MHz to 1.5 MHz of the broadband color difference signal (processing signal) and converts it to the above low frequency. Converted high-definition signal Y'□1 or "H
2 and a conventional narrowband color-difference signal (Q signal).

Effect The present invention uses the above-described configuration to separate the high-definition signal YH in the approximately 2 MHz band into Yl (1 and Yl2), add one to the Q signal, and add the other to the band-limited engineering signal. It is possible to transmit the high-frequency signal of the luminance signal as high-definition information within a band that is almost the same as the signal band, and it is possible to obtain a television signal with less interference.In addition, the engineering signal can be transmitted at the same frequency as the Q signal, from 0 to 500 KHz. Even if the band is limited, the drop in color signal transients seems to have little effect when using currently commercially available television receivers.
This is because only 100% of the bandwidth is used. Even if this signal is received by a current television receiver, the degree of interference will be almost the same as before.

Embodiment Hereinafter, a high-definition signal generating device according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1a shows a block diagram of a high-definition signal generating device according to an embodiment of the present invention, and FIG. 1b shows a block diagram of a corresponding high-definition signal receiving device.

In Figure 1a, the broadband luminance signal Y input from a signal source such as a camera is passed through two bypass filters (HPF).
22 and 24 and two subtracters 21 and 23, YL and the first
and a second high frequency component Y□, and Yl2. The frequency spectrum is shown in Figure 2a. First high-definition information YI
I is subcarrier aos2xf8°t(fsa
is 3. ssMHz) and frequency shifted by extracting the lower sideband signal with a bandpass filter (BPF) 32. In other words, YHl is 5in2
If πft, the output C of the multiplier is c=A#5in2πftlIC082πf8c.

== (51n2π(f+fB C)t+5in2π(
f-, fsc)t), and the second term is extracted.l The frequency f of Yl1 is shifted by fsc and becomes f
−f, . On the other hand, the frequency of the second high-definition information YH2 is similarly shifted, but since the frequency of the carrier wave input to the second frequency converter 4 is 1.25 fsc, the frequency after conversion is f-1,2ts fsa. becomes. 2nd Na
As shown in the frequency spectrum of the second high-definition signal Y
l(2 usually selects the 6.2-6.2 MH2 band, so f-1,2sfsc is about 0.7-1.7 MHz.

Frequency shifted signal Y'8. and “H2 is the first and second
adders 6 and 6 add the two narrowband color difference signals. Here, it is assumed that the broadband color difference signal (engineering signal) is limited in band by a low-pass filter 10 in advance to a range of 0 to 500 KH2, which is equivalent to the Q signal. On the other hand, the first and second high-definition signals each have a frequency of approximately 0.6 to 1.6 MHz.
and has a signal band of approximately Q, 7 to 1.7 MHz, so
1st. The output of the second adder has approximately the same bandwidth Q~1
．． It will have a frequency of 7MHz. Thereafter, both signals are subjected to quadrature two-phase modulation using subcarriers, and then added to YL in an adder 11.

The signal received in FIG. 1 is separated by a luminance/color difference signal separation circuit 12 into YL, a color difference signal, and a high frequency component X/ of the brightness signal. The color difference signal and Y'□ are demodulated by synchronous detectors 13 and 14. One synchronous detector 13 separates the Q signal and Y'□, and a bypass filter 15 and an adder 19 further separate the Q signal and Y'
Separated into □.

The other synchronous detector 14 separates the narrowband signal and Y'H2, and the second filter 17 further separates the signal into the narrowband signal and Y'H2. The above two Y′□.

and "H2 are converted into the original high-definition signals YH4 and Y)12 by frequency converters 61 and 62, and sent to an adder 60.

YL is added to obtain a wideband luminance signal.

FIGS. 2&d show frequency spectra of embodiments of the invention. The area YL111Q in the figure has the same frequency characteristics as the current television system, and "Hl" and "+(2) are newly inserted high-definition information. The feature of the present invention is that the first high-definition signal Y
ill is frequency-converted using the subcarrier cO52πfsct and Q
signal and add the second high-definition signal YH2 to another carrier C
082,5πfsct and add it to the band-limited engineering signal (Z/multiple signal. In this case, the high-definition signal YH4 is 4.2 to 5.2 MHz, Y
, by using a total of 2 MHz band from 5.2 to 6.2 MHz, and by band-limiting the engineering signals that are not effectively used, 1. sMH
It becomes possible to transmit within the z band. Since current television receivers do not use the 0.6-1.5 MHz band for industrial signals, it is possible to add high-definition information in the 2 MHz band within the occupied band, which is almost the same as that for NTSC signals. Furthermore, even if this signal is received by a current receiver, it is thought that the interference caused by the subcarrier to the luminance signal will hardly increase. Note that in the embodiment, the first high-definition signal Y
I) 11 is added to I' times the signal, and the second high-definition signal Y')
Although I2 was added to the Q signal, it may be reversed.

Effects of the Invention As described above, the present invention divides the high-frequency component of a luminance signal as high-definition information into two bands, frequency-converts both to a low-frequency band, adds one to the high-frequency band of the Q signal, and adds the other to the high-frequency band of the Q signal. By adding it to the high frequency range of the optical signal (I' times signal) converted into a narrowband signal, it is possible to construct a high-definition signal generating device that causes less interference to current television receivers.

[Brief explanation of drawings]

FIG. 1q is a block diagram of a high-definition signal generating device in an embodiment of the present invention, FIG. 1 is a block diagram of a corresponding high-definition signal receiving device, and FIG. 2 is a block diagram of the embodiment of FIG. 1 is a diagram showing a frequency spectrum for explanation. FIGS. 3 and 4 are block diagrams of a conventional high-definition signal conversion device. FIG. 5 is a frequency spectrum diagram thereof. 2... High-definition signal separator 13... Second frequency converter, 4... First frequency converter, 6...
Mark: First adder, 6...Second adder, 9.
...Modulator, 1o ...Low pass filter, 11 ...Adder, 12 ...Brightness.
Color signal separator, 16... Demodulator, 17...
-First filter 118...-Second filter, 50...Adder, 61...First frequency converter, 62...Second frequency converter. Name of agent: Patent attorney Toshio Nakao and 1 other person
1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (2)

[Claims] (1) Input a wideband luminance signal and select a specific frequency f_1
A first high-definition signal having a higher frequency component, a second high-definition signal higher than another specific frequency f_2 (f_2<f_1) and lower than the above frequency f_1, and the above frequency f_
a high-definition signal separator that outputs a low-band luminance signal having components in a lower range than 2; and a first frequency that inputs the first high-definition signal and outputs a low-band-converted first high-definition signal. a converter, a second frequency converter that inputs the second high-definition signal and outputs a second high-definition signal that has been low-frequency converted;
a first adder inputting the narrowband color difference signal and the second high-definition signal subjected to low frequency conversion and outputting a first non-modulated signal; and a first adder inputting the wideband color difference signal and outputting a second narrowband color difference signal. a second adder that inputs the second narrowband color difference signal and the low-pass converted first high-definition signal and outputs a second non-modulated signal; A high-definition signal generator for television signals, which is configured with a modulator that inputs a second unmodulated signal and a carrier wave and performs orthogonal two-phase modulation, and is capable of transmitting a high-definition signal. (2) Input a wideband luminance signal and select a specific frequency f_1
A first high-definition signal having a higher frequency component, a second high-definition signal higher than another specific frequency f_2 (f_2<f_1) and lower than the above frequency f_1, and the above frequency f_
a high-definition signal separator that outputs a low-band luminance signal having components in a lower range than 2; and a first frequency that inputs the first high-definition signal and outputs a low-band-converted first high-definition signal. a converter, a second frequency converter that inputs the second high-definition signal and outputs a second high-definition signal that has been low-frequency converted;
a first adder that inputs the narrowband color difference signal and the low-pass converted first high-definition signal and outputs a first non-modulated signal; and a first adder that inputs the wideband color difference signal and outputs a second narrowband color difference signal. a second adder that inputs the second narrowband color difference signal and the low-pass converted second high-definition signal and outputs a second non-modulated signal; A high-definition signal generator for television signals, which is configured with a modulator that inputs a second unmodulated signal and a carrier wave and performs orthogonal two-phase modulation, and is capable of transmitting a high-definition signal.