JPS63117581A - High definition information multiplex circuit - Google Patents

Abstract

PURPOSE:To prevent occurrence of deterioration of picture quality at part of a picture signal in which inter-field correlation is absent by using each inter- field difference signal of a luminance/color signal of a TV signal to control the multiplicity of high definition information. CONSTITUTION:High definition information YH is separated from a luminance signal Y by an HPF 3 and a low frequency component YL is separated by a subtractor 4. The information YH goes to a high definition information low frequency conversion signal YH' by a low frequency conversion circuit 5, the output YL of the subtractor 4 is added (6) to a color signal C to obtain an NTSC signal. The NTSC signal and the signal YH' are added (7) to obtain a high definition signal EDTV. A signal from a delay circuit 8 is subtracted (9) is subtracted from the signal Y to obtain an inter-field difference signal YF. The signal of a delay circuit 10 is subtracted (11) from the signal C to obtain an inter-field difference signal CF. The signals YF, CF are added (15) via absolute value circuits 13, 14, its output A is sent to a discrimination circuit 16, the total sum A and a setting value B are compared (17), a control signal S relating to the multiplexing of the signal YH' is sent to control the operation of a changeover circuit 19.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a television signal processing circuit, and in particular, it is capable of transmitting high-definition information while maintaining complete communication with the current television system, the NTSC system. Regarding multiplexing circuits.

[Conventional technology]

Conventionally, this type of high-definition information multiplexing circuit has a 4-field sequence similar to the subcarrier of the color signal, and when compared between fields with respect to the subcarrier, the phase is 18
High-definition information Y of luminance signal using 0° different carriers
l( is modulated.

As a result, a high-definition information low-band conversion signal YH' is obtained by converting the high-definition information luminance signal YI+ to a low band, and this high-definition information low-band conversion signal YH' is converted into color difference signals I and Q using subcarriers. The luminance signal is multiplexed with the modulated color signal. In this way, high-definition information can be transmitted while maintaining complete communication with the current NTSC system.

[Problem that the invention seeks to solve]

The conventional high-definition information multiplexing circuit described above is based on the premise that the brightness signal, color signal, and high-definition information low-band conversion signal YH' are separated by performing calculations between fields. ′ are multiplexed. However, in the part where the high-definition information low-frequency conversion signal YII' is multiplexed,
Since it does not have a circuit that controls multiplexing of this signal using the inter-field difference signal, the inter-field difference signal is combined with the high-definition information low-frequency conversion signal YH' based on the part of the image signal that has no inter-field correlation. , deterioration of image quality occurred.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a high-definition information multiplexing circuit that prevents image quality deterioration from occurring in portions of an image signal where there is no inter-field correlation.

[Means for solving problems]

The present invention uses inter-field difference signals of the luminance signal and chrominance signal of a television signal in a circuit that multiplexes high-definition information on the premise that high-definition information is separated by performing inter-field calculations. The apparatus is equipped with a control means for controlling multiplexing of high-definition information.

Therefore, since the control means controls the multiplexing of high-definition information using the inter-field difference signals of the luminance signal and chrominance signal of the television signal, the inter-field difference signal is The difference is no longer multiplexed as high-definition information, and image quality deterioration can be prevented.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 shows an embodiment of a high-definition information multiplexing circuit according to the present invention. In the figure, a brightness signal Y and a color signal C in a television signal are input manually to input terminals 1 and 2, respectively.

The luminance signal Y passes through a bypass filter 3 to separate high-definition information NY□, and a subtracter 4 subtracts high-definition information YH from the luminance signal Y to separate the low frequency component YL of the luminance signal. . In addition, the high-definition information YH passes through a low-frequency conversion circuit 5 that frequency-converts the high-frequency components of the luminance signal and converts them into low-frequency components, and is separated from the color signal by performing inter-field calculations. Detailed information low frequency conversion signal YH'
becomes.

Further, the output YL of the subtracter 4 is converted into a color signal C by the adder 6.
is added to form the current NTSC signal. Further, by adding the NTSC signal and the high-definition information low-frequency conversion signal YH' as the output of the low-frequency conversion circuit 5 using an adder 7, an EDTV (E:<tended Definition TV
) signal is obtained.

On the other hand, the luminance signal Y is subtracted by the subtracter 9 from the signal that has passed through the 263-line delay (263H delay) circuit 8, and the inter-field difference signal Y of the luminance signal Y is obtained as an output. In the conventional system, the circuit consisting of the delay circuit 8 and the subtracter 9 is a circuit that separates the color signal C on the receiver side, and the inter-field difference signal YF obtained by inputting the luminance signal Y to this circuit. is the luminance signal Y
The color signal C included in the color signal C is a component that cannot be separated.

Similarly to the luminance signal Y, the chrominance signal C is divided into a signal passed through a 262 line delay (262H delay) circuit 10 and a subtracter 11.
The inter-field difference signal CF of the color signal C is obtained as an output. Here, the circuit consisting of the 262-line delay circuit 10 and the subtracter 11 is a circuit that separates the high-definition information low-frequency conversion signal Y, / on the receiver side in the conventional system, and the color signal C is sent to this circuit. The inter-field difference signal C2 obtained by inputting the luminance signal Y included in the color signal C is a component from which the luminance signal Y cannot be separated.

Inter-field difference signal YF obtained as above
and CF are components that cannot be separated into the luminance signal Y and color signal C, and the high-definition information low-frequency conversion signal YH' is the luminance signal Y.
Since it is a signal obtained based on , it can be said that the high-definition information low-frequency conversion signal YH' and the color signal C are components that cannot be separated. Therefore, ° field difference signals YF and C
2 is output, the high-definition information low-frequency conversion signal Y□
It is necessary to stop multiplexing ′.

The 263-line delay circuit 8, the 262-line delay circuit 10, and the 2A calculator 9.11 are connected to a first circuit 12 that obtains inter-field difference signals of the luminance signal and chrominance signal of the television signal.
Configure. The interfield difference signal Yp as the output of this first circuit 12, that is, the output of the subtracters 9 and 11.
and C2 are supplied to absolute value circuits 13 and 14, respectively, and their absolute values are taken. The outputs of these absolute value circuits 13 and 14 are added by an adder 15, and the output A
is supplied to the comparator 17 of the determination circuit 16. The absolute value circuits 13 and 14 and the adder 15 receive inter-field difference signals Yp and CF of the luminance signal and chrominance signal from the first circuit 12.
A second circuit 18 that takes the absolute value of and calculates the sum A.
Configure.

The determination circuit 16 compares the sum A (the sum of the respective absolute values of the inter-field difference signals YF and Cp) from the adder 15 of the second circuit 18 with the set value B in the comparator 17, and calculates the high-definition information. It determines whether to multiplex the low-frequency converted signal Yl(') and sends out a control signal (multiplexing control signal) S indicating whether to multiplex the high-definition information low-frequency converted signal Y□'.

Here, the comparator 17 outputs L(
A low (1) level signal is sent out, and if A<8, an H (high) level signal is sent out as the output S.

The changeover switch 20 of the changeover circuit 19 is connected to the comparator 1'7. Based on the multiplex control signal S from , switching to the L side or the H side is controlled. That is, the multiple control signal S
is at the L level, the selector switch 20 is switched to the L side, and the NTSC signal is outputted via the output terminal 21. Further, if the multiplex control signal S is at H level, the selector switch 20 is switched to the H side, and the EDTV signal is transferred to the output terminal 2.
It will be output via 1. In addition, selector switch 2
As 0, an appropriate device such as an electronic switch is used.

As described above, it is composed of the first circuit 12, the second circuit 18, the determination circuit 16, and the switching circuit 19, and uses the inter-field difference signals of the luminance signal and chrominance signal of the television signal to perform high-definition information low-frequency conversion. By using a control means for controlling the multiplexing of the signal YH', the inter-field difference signal is converted into the high-definition information low-frequency conversion signal Y in the part of the image signal where there is no inter-field correlation
H' is not multiplexed. Therefore, image quality deterioration does not occur in parts of the image where there is no inter-field correlation.

It goes without saying that the present invention is not limited to the embodiments described above, and that various applications and modifications can be made without departing from the gist of the present invention.

[Effects of the Invention] As described above, according to the high-definition information multiplexing circuit according to the present invention, the control means for controlling the multiplexing of high-definition information using the inter-field difference signals of the luminance signal and color signal of the television signal is provided. By using this method, the difference signal between fields will not be multiplexed as high-definition information in the part of the image signal where there is no inter-field correlation, and there will be no image quality deterioration in the part of the image signal where there is no inter-field correlation. be effective.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of a high-definition information multiplexing circuit according to the present invention. 12...First circuit, 16...Determination circuit, 18...Second circuit, 19...Switching circuit. Applicant: NEC Corporation Representative

Claims (1)

[Claims] 1. In a circuit that multiplexes high-definition information on the premise that high-definition information is separated by performing inter-field calculations, each inter-field difference signal of a luminance signal and a chrominance signal of a television signal is 1. A high-definition information multiplexing circuit characterized by comprising a control means for controlling multiplexing of high-definition information using the control means. 2. The control means includes a first circuit that obtains inter-field difference signals of a luminance signal and a chrominance signal of a television signal;
A second circuit calculates the sum of the absolute values of the inter-field difference signals of the luminance signal and chrominance signal from the first circuit, and a second circuit calculates the sum of the absolute values of the inter-field difference signals of the luminance signal and color signal from the first circuit, and compares the sum from the second circuit with a set value to obtain high-definition information. A determination circuit that determines whether or not to perform multiplexing and sends out a multiplex control signal; and a switching circuit that switches whether or not to multiplex and output high-definition information based on the multiplex control signal from this determination circuit. A high-definition information multiplexing circuit according to claim 1, characterized in that it is comprised of: