JP3097518B2 - Wide television signal transmission device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a second generation EDTV.
(Wide clear vision) In broadcasting, the present invention relates to a wide television signal transmission apparatus to which a black clip circuit for preventing loss of synchronization in a receiver or studio equipment is applied.

[0002]

2. Description of the Related Art FIG. 4 shows a configuration of a conventional wide television signal transmission apparatus.

In FIG. 4, reference numeral 501 denotes a luminance signal (Y);
502 is a color signal (I), 503 is a color signal (Q), 504
Is a horizontal LPF for passing a horizontal frequency of 1 MHz or less of the luminance signal (Y) 501, and 505 is one of the luminance Y components 501.
Horizontal BP to pass horizontal frequency of ~ 4.2MHz range
F and 506 are horizontal HPFs that pass a horizontal frequency of 4.2 MHz or more of the luminance signal (Y) 501, 507 is a horizontal LPF that passes a 1.5 MHz horizontal frequency of the chrominance signal (I) 502, and 508 is a chrominance signal ( Q) 503 at 0.5 MH
This is a horizontal LPF that passes the horizontal frequency of z.

A vertical HPF 509 extracts a component of 360 TV or more from a component of 1 MHz or less in the horizontal direction.
Reference numeral 510 denotes a vertical LPF that extracts 360 TV vertical components or less from horizontal 1 MHz or lower components, and 511 denotes a horizontal BPF.
The vertical LPF connected to 505 and 512 are horizontal HPFs
The vertical LPF 513 connected to the reference numeral 06 is a horizontal LPF 50
5, a vertical LPF 514 is connected to a horizontal LPF 505.
Is connected to the vertical LPF.

[0005] Reference numeral 515 denotes a 4 connected to the vertical HPF 509.
-3 converter, 516 is connected to the vertical LPF 509
-3 converter, 517 is connected to the vertical LPF 511
-3 converter, 518 is connected to the vertical LPF 512
-3 converter, 519 is connected to the vertical LPF 513
-3 converter, 520 is connected to the vertical LPF 514
-3 converter.

Reference numeral 521 denotes a time LPF connected to the 4-3 converter 515, 522 denotes a vertical HPF connected to the 4-3 converter 516, and 523 denotes a vertical LPF connected to the 4-3 converter 516. Time LPF 525 connected to 4-3 converter 517 is a time LPF connected to 4-3 converter 518, and 526 is a sequential-interlace converter connected to 4-3 converter 519, and 527 is 4- 3 is a sequential-interrupt converter connected to the converter 520, 528 is a sequential-interrupt converter connected to the time LPF 521, and 529 is a vertical HPS 52.
2 is connected to the sequential-interlacing converter, and 530 is a vertical LPS.
A sequential-to-jump converter connected to 523, and a time L
Sequential-to-interlace converter 532 connected to PF 524 is a sequential-to-interlace converter connected to time LPF 525.

Reference numeral 533 denotes a modulator for fsc modulating the output of the sequential-interlace converter 526, and 534 denotes a sequential-interlace converter 527.
A modulator 535 modulates the output of fSC with f _SC, a modulator 533,
An adder 534 that adds the outputs of 534 and outputs a color signal 584, an adder 536 that adds the VH signal 580 and the VT signal 581 output from the sequential-interlace converters 528 and 529, and 537 is a sequential-interlace converter An adder 538 that adds the outputs from 530 and 531 to output a main image portion luminance signal, and 538 outputs the output of the sequential-interlace converter 532 to 16/7
f _SC modulated by a modulator for outputting a HH signal 538, 539
Is an adder for adding the color signal 584 and the HH signal 538.

Reference numeral 540 denotes a main picture section correlation circuit connected to the adder 536; 541, a horizontal LPF; 542, a modulator for fsc modulating an output from the main picture section correlation circuit 540;
Is a self-bias circuit connected to the modulator 542,
Reference numeral 5 denotes an adder 546 that adds the output signal of the adder 539 and the main image portion luminance signal 582 and outputs a main image portion signal 586.
Is a non-image portion reinforcing signal 58 from the self-bias circuit 543.
A combiner multiplexing 5 into the non-image portion and a main image portion signal 586 into the main image portion; and 548, an adder that adds the synchronization signal and the burst signal to the output from the synthesizer 546 and outputs a letterbox signal 549; Reference numeral 547 denotes a black clip circuit connected to the adder 548.

In the conventional wide television signal transmission apparatus configured as described above, a wide television signal (aspect ratio 16: 9, 525 scanning lines, sequential scanning 1:
Among the signal sources 1), the luminance signal (Y) 501 is converted to a horizontal LP.
1 MHz or less, 1 to 4.2 MHz, 4.2 by F504, horizontal BPF 505, and horizontal HPF 506, respectively.
Each is separated into components of MHz or more. From the horizontal 1 MHz or lower components, the vertical HPF 509 extracts the vertical 360 TV or more components, and the 4-3 converter 515, time LP
A VH signal 580 having a vertical high frequency component multiplexed into 120 TV portions (hereinafter, referred to as a non-image portion) is created by the F521 and the sequential-interlacing converter 528 in accordance with the top and bottom of the screen.

The components of 360 TV lines or less extracted by the vertical LPF 510 are subjected to 4-3 conversion by a 4-3 converter 516, and then converted to a vertical HPF 522 and a vertical LPF 52.
In step 3, the components are separated into the following components and more than the vertical 180 TV lines.
A VT signal 581 having a moving image vertical high frequency component is created. Also,
Components below 180 TV vertical are 1-4.2 MHz horizontal
Are similarly subjected to 4-3 conversion by the 4-3 converter 523, and sequentially added by the adder 537 to the signal obtained by the interlace conversion by the -jump converter 530, and 360 parts at the center of the screen (hereinafter, referred to as Main picture section luminance signal 58 multiplexed with the main picture section)
Make 2.

[0011] The horizontal 4.2 MHz or higher component is converted to the vertical LP.
In the F512 system, components of 180 TV lines or less are extracted, subjected to 4-3 conversion and sequential-jump conversion, and then converted to 16/7.
An HH signal having f _SC modulation and a horizontal high-frequency component is created.

The color signal (I) 502 and the color signal (Q)
Reference numeral 503 denotes horizontal LPFs 507 and 508, each of which is limited to a horizontal frequency of 1.5 MHz or less and a horizontal frequency of 0.5 MHz or less.
_The color signals 584 that are _SC- modulated and added by the adder 534 are generated.

The main picture section luminance signal 582, HH signal 583, and color signal 584 are added by an adder 545, and multiplexed as a main picture section signal 586 by a combiner 546 on the main picture section. Further, the VH signal 580 and the VT signal 581 are added by an adder 536 in order to reduce visual interference, and then the main signal is added to the main image portion luminance signal 582 using a correlation with a horizontal component of 1 MHz or less. The level is reduced by the image correlation circuit 540, the f _SC modulator 542 and the self-bias circuit 543 perform processing to make the image more difficult to see, and are multiplexed as a non-image part reinforcement signal 595 by the combiner 546 on the non-image part.
The signal multiplexed into the main image portion and the non-image portion becomes a letterbox signal 549 by adding a synchronization signal and a burst signal in an adder 548.

Conventionally, when transmitting this signal, NT
As in the case of transmitting the SC signal, the letterbox (composite) signal is clipped by the black clipping circuit 547 and then sent to the video carrier modulator. The operation of the black clip circuit 547 will be described below by taking the configuration of NTSC signal transmission as an example.

FIG. 5 is a block diagram showing a configuration of a black clip circuit in NTSC signal transmission.

In FIG. 5, a luminance signal (Y) 401
When a component similar to the synchronizing signal, that is, a signal having a low horizontal frequency and a large negative level is generated in the video signal portion of the composite signal output formed from the color signal (I) 402 and the color signal (Q) 403. Is indistinguishable from a synchronizing signal, so that the synchronizing clock circuit of the receiver or the studio equipment malfunctions and normal processing cannot be performed. Therefore, when transmitting the composite signal 449, the black clip circuit 447 is used to prevent malfunction.

That is, by using the black clipping circuit 447 having the frequency characteristic diagram shown in FIG. 6 (for example, the black clipping characteristic of D2-VTR), the level of the horizontal low-frequency signal is prevented from becoming a large negative value. Clip it. For example, when the composite signal component has a level equal to or lower than the solid line in FIG. 6, a process of rounding to the value of the solid line is performed.

Note that this black clip circuit is shown in FIG.
Of which R is the input / output characteristic (address-data characteristic)
It can be configured by using OM.

[0019]

SUMMARY OF THE INVENTION A main picture area luminance signal, a non-picture area reinforcement signal component, which are signal components of a letter box signal,
The color signal and the HH signal have frequency characteristics shown in FIGS.

That is, a portion 71 shown in FIG. 7 is a main image portion luminance signal component, and the upper limit of the signal level is about 100 IRE.
It is. A portion 81 shown in FIG. 8 is a non-image portion reinforcement signal component, which is limited to ± 15 IRE at the time of modulation, and further decreases by -5 IRE due to self-bias. A portion 91 shown in FIG. 9 represents a color signal component, and a portion 92 represents an HH signal component. The color signal is in a range of about ± 60 IRE, and the HH signal is in a range of about ± 25 IRE.

Here, the vertical LPF 523 and the vertical HPF 522 that generate the main picture area luminance signal 582 and the VT signal 581 are S
SKF (Symmetric Short Kerne)
lFilter), and the respective SSKF frequency characteristics are as shown in FIG. 10 and FIG.

At this time, if the signal source has a horizontally long, bright and dark horizontal line having a component of about 120 TV lines in the vertical direction, the vertical LPF 523 performs a filtering process in which the gain exceeds 1, and the vertical LPF 523 performs horizontal filtering of the main image portion luminance signal. A large negative signal component (part 72 shown in FIG. 7: the lower limit of the signal level is about −12 IRE) is generated in a low frequency part.

However, in the black clipping circuit 547, only the clipping based on the characteristic shown in FIG. 6 transmits a part of the signal component without being clipped.
Synchronization disturbance may occur in the receiver or studio equipment. Further, since black clipping is performed on the composite signal, it is impossible to simply increase the clipping level.

The present invention provides a wide television signal transmission apparatus for performing black clipping of a signal component to be transmitted in a second generation EDTV (wide clear vision) broadcast to prevent loss of synchronization in a receiver or studio equipment. The purpose is to:

[0025]

SUMMARY OF THE INVENTION In order to solve this problem, the present invention relates to a transmission apparatus for a wide television signal, which converts a wide television signal having an aspect ratio of 16: 9 into a television having an aspect ratio of 4: 3. In order to have the compatibility with the signal standard and to transmit, the information of the wide horizontal television signal converted from the progressive scanning to the interlaced scanning which is multiplexed into about 3/4 of the center in the vertical direction of the screen in the luminance horizontal low band A black clipping circuit for clipping and outputting the signal level of the component with a constant negative value is newly added.

Thus, a signal having a large negative level of a horizontal low-frequency component generated in the main image portion luminance signal can be clipped, and synchronization disturbance generated by a receiver or studio equipment can be prevented.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention relates to a transmission apparatus for a wide television signal, which converts a wide television signal having an aspect ratio of 16: 9 into a television having an aspect ratio of 4: 3. In order to have the compatibility with the television signal standard and to transmit the information, the information of the wide television signal converted from the interlaced scanning to the interlaced scanning, which is multiplexed into about 3/4 of the central portion of the screen in the vertical direction, has the same brightness level and low level. A first black clip circuit for clipping and outputting the signal level of the band component at a constant negative value, and a wide television signal converted from the progressive scan to the interlaced scan to the output signal of the first black clip circuit Of the horizontal and high-frequency components of the luminance and the color components are modulated and added together, and the wide television signal multiplexed to approximately 1/8 of the upper and lower parts of the screen is skipped from the sequential scanning. A synthesizer for synthesizing 120 TV scanning line difference signals out of information lost during the conversion, and a constant negative and constant level of a signal obtained by adding a synchronization signal and a burst signal to the output signal of the synthesizer. And a second black clipping circuit for clipping a signal having a large negative level of a horizontal low-frequency component generated in the main image portion luminance signal, and transmitting the signal. Prevents synchronization disturbances that occur in receivers and studio equipment.

Hereinafter, embodiments of the present invention will be described with reference to FIGS.
This will be described with reference to FIG. FIG. 1 shows a configuration of a wide television signal transmission apparatus according to an embodiment of the present invention.

In FIG. 1, reference numeral 101 denotes a luminance signal (Y);
102 is a color signal (I), 103 is a color signal (Q), 104
Is a horizontal LPF that passes a horizontal frequency of 1 MHz or less of the luminance signal (Y) 101, and 105 is 1 of the luminance Y component 101.
Horizontal BP to pass horizontal frequency of ~ 4.2MHz range
F and 106 are horizontal HPFs that pass the horizontal frequency of 4.2 MHz or more of the luminance signal (Y) 101, 107 is a horizontal LPF that passes the 1.5 MHz horizontal frequency of the chrominance signal (I) 102, and 108 is a chrominance signal ( Q) 0.5 MH of 103
This is a horizontal LPF that passes the horizontal frequency of z.

Reference numeral 109 denotes a vertical HPF for extracting 360 TV vertical components or more from horizontal 1 MHz or lower components;
110 is a vertical LPF for extracting 360 TV vertical components or less from horizontal 1 MHz or lower components, and 111 is a horizontal BPF.
A vertical LPF connected to 105, 112 is a horizontal HPF 1
06 is connected to the vertical LPF 10 and the horizontal LPF 10
5, the vertical LPF 114 is connected to the horizontal LPF 105.
Is connected to the vertical LPF.

Numeral 115 denotes a 4 connected to the vertical HPF 109.
-3 converter, 116 is connected to the vertical LPF 109 4
-3 converter, 117 is connected to the vertical LPF 111
-3 converter, 118 is connected to the vertical LPF 112
-3 converter, 119 is connected to the vertical LPF 113
-3 converter, 120 is 4 connected to the vertical LPF 114
-3 converter.

Reference numeral 121 denotes a time LPF connected to the 4-3 converter 115; 122, a vertical HPF connected to the 4-3 converter 116; 123, a vertical LPF connected to the 4-3 converter 116; The time LPF connected to the 4-3 converter 117, 125 is the time LPF connected to the 4-3 converter 118, and 126 is the sequential-interlace converter connected to the 4-3 converter 119, and 127 is 4- 3 is a sequential-jump converter connected to the converter 120, 128 is a sequential-jump converter connected to the time LPF 121, and 129 is a vertical HPS 12
2 is a sequential-to-jump converter, 130 is a vertical LPS
A sequential-interlaced converter connected to 123, 131
132 is a sequential-interrupt converter connected to the PF 124, and 132 is a sequential-interrupt converter connected to the time LPF 125.

Reference numeral 133 denotes a modulator for _fsc modulating the output of the sequential-interlace converter 126, and reference numeral 134 denotes a sequential-interlace converter 127.
A modulator for _fSC modulating the output of the modulator 135 is a modulator 133,
An adder 134 adds the output of 134 and outputs a color signal 184, 136 is an adder for adding the VH signal 180 and the VT signal 181 output from the sequential-interlacing converters 128 and 129, and 137 is a sequential-interlacing converter. An adder 138 that adds the outputs from 130 and 131 to output a main image portion luminance signal outputs a signal 138 to the output of the sequential-interlacing converter 132 at 16/7.
f _SC modulated by a modulator for outputting a HH signal 138, 139
Is an adder for adding the color signal 184 and the HH signal 138.

Further, 140 is the main picture portion correlation circuit connected to the adder 136, 141 horizontal LPF, 142 is a modulator of f _SC modulating an output from the main picture portion correlation circuit 140, 143
Is a self-bias circuit connected to the modulator 142;
Reference numeral 4 denotes a first black clip circuit that clips the signal level of the horizontal low-frequency component of the main image portion luminance signal 182 with a constant negative value, and 145 adds the output signal of the black clip circuit 144 with the output signal of the output signal adder 139. And the main picture signal 186
146 is a self-bias circuit 143
The non-image part reinforcement signal 185 from the main image part signal 1
A synthesizer multiplexes 86 into the main picture section, and 148 denotes a synthesizer 146.
The adder 147 that adds the synchronization signal and the burst signal to the output from the controller and outputs a letterbox signal 149 is a second black clip circuit connected to the adder 148.

Next, the operation of the present embodiment configured as described above will be described. From a signal source of a wide TV signal (aspect ratio 16: 9, 525 scanning lines, sequential scanning 1: 1), a VH signal 180 having a vertical high-frequency component, a VT signal 181 having a moving image vertical high-frequency component, a main image Main section luminance signal 182 multiplexed in the section, HH signal 1 having a horizontal high-frequency component
83 and the chrominance signal 184 are produced in the same manner as in the conventional wide television signal transmission apparatus shown in FIG.

Hereinafter, the operation of the black clip circuit 144 and the subsequent steps, which is a characteristic part of the present embodiment, will be mainly described.

Since the main image portion luminance signal 182 has the components shown in FIG. 7, when a signal below the level of the solid line 21 (-5 IRE in this example) shown in FIG. A clip process for rounding to the level indicated by the solid line 21 in FIG. 2 is performed. The HH signal 183 and the chrominance signal 184 each have the components shown in FIG. 9. However, since these may be clipped as a composite signal, they are added by an adder 189 and further added to the black clip circuit 144. The output signal and the adder 145 are added, and the result is multiplexed as the main image signal 186 by the synthesizer 146 on the main image.

The VH signal 180 and the VT signal 181
Are added by an adder 136 in order to reduce visual disturbance, and then the horizontal 1M of the main image portion luminance signal 182 is added.
Main image portion correlation circuit 140 using the correlation with the component below Hz.
To reduce the signal level, and furthermore, the f _SC modulator 14
2 and the self-bias circuit 143, a process for making the image more invisible is performed to obtain a non-image portion reinforcement signal 185. After this signal is multiplexed into a non-picture part by the synthesizer 146, a synchronizing signal and a burst signal are added by the adder 184 together with the main picture part signal 186, and transmitted as a letterbox signal 189.

At this time, since the non-picture part reinforcement signal 185 has the components shown in FIG. 8, and the HH signal 183 and the color signal 184 have the components shown in FIG. 8, clip processing as a composite signal is performed. What is necessary is just to prevent a component with a large negative level from being generated due to the influence of noise or the like. Therefore, the level of the solid line 31 shown in FIG.
RE) When the following signals are generated, the clip processing for rounding to the level of the solid line 31 in FIG.

As described above, according to the present embodiment, a signal having a large negative level of the horizontal low-frequency component generated in the main image portion luminance signal can be clipped, and the modulated component can be abruptly caused by noise. Large negative level signal can be clipped.

Further, since the frequency characteristics of the black clip circuit are constant, the black clip circuit can be easily configured with only the comparator and the selector, and can be realized at lower cost than the configuration using the ROM.

[0042]

As described above, according to the present invention, a signal having a large negative level of a horizontal low-frequency component generated in a main picture portion luminance signal can be clipped, and a modulated component can be abruptly caused by noise. Since a signal with a large negative level can be clipped, it is possible to prevent synchronization disorder generated by a receiver or studio equipment.

Further, there is an effect that the black clip circuit can be constituted by an inexpensive circuit including only a comparator and a selector.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a wide television signal transmission apparatus according to an embodiment of the present invention.

FIG. 2 is a frequency characteristic diagram of a black clip circuit with respect to a main picture portion luminance signal of the wide television signal transmission apparatus according to one embodiment of the present invention;

FIG. 3 is a frequency characteristic diagram of a black clip circuit for a main picture signal and a non-picture part reinforcement signal of the wide television signal transmission apparatus according to one embodiment of the present invention;

FIG. 4 is a block diagram showing a configuration of a conventional wide television signal transmission device.

FIG. 5 is a block diagram showing a configuration of a black clip circuit in conventional NTSC signal transmission.

FIG. 6 is a frequency characteristic diagram of a conventional black clip circuit.

FIG. 7 is a frequency characteristic diagram showing a main image portion luminance signal component transmitted from a conventional wide television signal transmission device.

FIG. 8 is a frequency characteristic diagram showing a non-picture part reinforcement signal component transmitted from a conventional wide television signal transmission device.

FIG. 9 is a frequency characteristic diagram showing a color signal and an HH signal component transmitted from a conventional wide television signal transmission device.

FIG. 10 is a frequency characteristic diagram of an SSKF-LPF used in a conventional wide television signal transmission device.

FIG. 11 is a frequency characteristic diagram of SSKF-HPF used in a conventional wide television signal transmission device.

[Explanation of symbols]

101 Luminance signal (Y) 102 Color signal (I) 103 Color signal (Q) 104, 107, 108, 141 Horizontal LPF 105 Horizontal BPF 106 Horizontal HPF 109 Vertical HPF 110-114 Vertical LPF 115-120 4-3 converter 121 , 124, 125 hours LPF 122 vertical HPF 123 vertical LPF 126-132 sequential-interlacing converter 133, 134, 142 f _SC modulator 135-137, 139, 145, 146 adder 140 main image section correlation circuit 143 self-bias circuit 144 First black clip circuit 146 Combiner 147 Second black clip circuit

Claims (1)

(57) [Claims] An apparatus for transmitting a wide television signal, which is compatible with a television signal standard having an aspect ratio of 4: 3 and transmits a wide television signal having an aspect ratio of 16: 9. Of the information of the wide television signal converted from the progressive scanning to the interlaced scanning which is multiplexed to about 3/4 of the vertical center of the screen, the signal level of the luminance horizontal low-frequency component is clipped with a constant negative value. And a first black clip circuit for outputting the first horizontal signal and a luminance horizontal high-frequency component and a color component of the wide television signal converted from the progressive scanning to the interlaced scanning, respectively, in the output signal of the first black clip circuit. Out of the information that is lost when the wide-band television signal multiplexed in the upper and lower portions of the screen is converted from progressive scanning to interlaced scanning. A synthesizer for synthesizing the difference signal between 20 TV lines, and a second black clipping circuit for clipping a level of a signal obtained by adding a synchronizing signal and a burst signal to the output signal of the synthesizer with a constant negative value A wide-screen television signal transmission device comprising: