JPH0759052B2 - Dual screen tv - Google Patents

Description

TECHNICAL FIELD The present invention relates to a television having a wide screen aspect ratio (9:16) capable of receiving two types of signals, which are a high-definition television signal and a standard NTSC video signal. The present invention relates to a dual-screen television which is an additional function of a receiver.

2. Description of the Related Art In recent years, in dual-screen televisions, in addition to a tuner that receives a standard NTSC system broadcast wave, a dual-screen television has a tuner that receives a satellite broadcast, a dude that receives a text broadcast, and a high-definition television A device for receiving a John signal has come to be built in, and it has been added as one means or function for enhancing the additional function.

Hereinafter, an example of the conventional dual-screen television described above will be described with reference to the screen. FIGS. 4 and 5 are for explaining a conventional example. First, FIG. 4 is a block diagram of a double-screen dual-screen television compatible with Clear Vision (for example, Toshiba Review Vol. See "High-definition digital television" issued on December 1, 1987). In FIG. 4, 1
Is an input terminal of the video signal for the sub screen, 2 is the vertical direction of the video signal,
First sync signal reproducing circuit for generating horizontal sync pulse and clock, 6 is a spatial frequency filter for reducing aliasing distortion due to thinning, 7 and 8 are first, second for controlling thinning in the vertical and horizontal directions Thinning-out control unit, 9 and 10 are first and second frame memories, 11 is a frame synchronization circuit that controls reading and writing of the frame memories 9 and 10, 20 is an input terminal for the main screen video signal, and 22 is A second synchronizing signal reproducing circuit, 3 is a scanning line interpolating circuit for converting interlaced scanning to progressive scanning, and 39 and 40 are first and second selection switches for switching between a main screen image signal and a child screen image signal. , 30 designates the output position of the sub-screen and controls the selection switches 39, 40 to control the sub-screen of the main screen, and 14 and 15 double the data processing speed to complete the sequential scan conversion. The double speed conversion part, 31 is the output end of the combined video signal , 44 is an output terminal of the deflection pulse.

The operation of the dual-screen television configured as described above will be described below.

First, the operation of the frame synchronization circuit 11 will be described. FIGS. 5a and 5b are timing charts for explaining this operation. In FIG. 5, I is a sub-picture video signal, II is a main-picture video signal, III is a frame memory read / write timing, IV is a write timing, and V is a read timing. In addition, as shown in FIG.
The contents of two fields, A field and B field, are written in the frame memory. First, the frame memories 9 and 10 are read out by judging the field polarity of the video signal from the vertical and horizontal synchronizing pulses reproduced by the second synchronizing signal reproducing circuit 22 and written in the frame memories 9 and 10 by the judgment output. Alternately with the contents of the A field and the contents of the B field. On the other hand, writing is the first
From the vertical synchronizing pulse reproduced by the synchronizing signal reproducing circuit 2 of 1, a signal which alternately changes in field units is generated, and this output signal is used for A field and B field.
However, either one of the field polarity determination output of the video signal of the master screen, the picture output position of the slave screen output from the master screen slave screen switching control unit 30 and the relative position of the slave screen video signal with respect to the picture output position is selected. In the middle of writing for the field, it is predicted whether or not the read overtaking will occur, and if the overtaking occurs, the field to be written is reversed. (The writing speed is 1 / n compared to the reading speed because the data is thinned out to 1 / n.) For example,
When the contents of the i-th field in FIG. 5 are written for the B field, the reading outtakes the writing in the middle of the writing, so the contents of the i-th field are written for the A field.

Next, the deflection is performed by the vertical and horizontal pulses of the main screen video signal output from the second synchronization signal generation circuit 22.

However, in the above configuration, only the standard NTSC video signal can be input, and when the sync signal of the parent screen video is disturbed, the child screen is disturbed. Had.

In view of the above problems, the present invention provides (1) a dual-screen television capable of simultaneously displaying a high-definition television signal and video signals of two different standard NTSC systems. (2) Further, the present invention intends to provide a dual-screen television in which the child screen is not disturbed even if the sync signal of the parent screen video is disturbed.

Means for Solving the Problems In order to solve the above problems, the dual-screen television of the present invention is
(1) Standard NTSC video signal input terminal, first sync signal reproduction circuit connected to this input terminal, first time axis compression circuit, scanning line interpolation circuit, first spatial frequency A filter, a second time axis compression circuit connected to the output terminal of the scanning line interpolation circuit, first and second thinning control units connected to the output terminal of the first spatial frequency filter, The first and second thinning control units connected to the output terminals respectively
First and second frame memories, first frame synchronization circuit for controlling the first and second frame memories, output signal of the first time axis compression circuit and output signal of the first frame memory Selection switch for switching between, the second selection switch for switching the output signal of the second time axis compression circuit and the output signal of the second frame memory, and the outputs of the first and second selection switches. First and second double speed converters respectively connected to the terminals, a high-definition television signal input terminal, a second periodic signal reproducing circuit connected to the input terminal, and a second spatial frequency filter , Second
A third thinning control unit connected to the output terminal of the spatial frequency filter, a third frame memory connected to the output terminal of the third thinning control unit, and a second frame memory for controlling the third frame memory. Frame synchronization circuit, a third selection switch for switching the input video signal and the output signal of the third frame memory, the output signals of the first and second double speed conversion units, and the output of the third selection switch A fourth selection switch for switching the signal, a parent screen child screen switching control unit for controlling the fourth selection switch, a video signal output terminal connected to the output terminal of the fourth selection switch, the first, A fifth selection switch for switching the output pulse of the second synchronization signal reproducing circuit, an output terminal of the deflection pulse connected to the output terminal of the fifth selection switch, the first, second,
The main screen selection signal generator for controlling the third and fifth selection switches is provided. (2) Further, the present invention includes an input terminal for a standard NTSC video signal, a first synchronizing signal reproducing circuit connected to the input terminal, a first time axis compression circuit, and a scanning line interpolation circuit. , A first spatial frequency filter, a second time axis compression circuit connected to the output terminal of the scanning line interpolation circuit, and first and second first time connected to the output terminal of the first spatial frequency filter. A thinning control section, a first selection switch for switching between the output signal of the first time axis compression circuit and the output signal of the sixteenth time axis compression circuit, the output signal of the second time axis compression circuit, and the second A second selection switch for switching the output signal of the thinning-out control unit;
First and second frame memories respectively connected to the output terminals of the selection switches, a first frame synchronization circuit for controlling the first and second frame memories, and the first and second frame memories.
First and second double speed converters respectively connected to the output terminals of the frame memory, an input terminal for a high-definition television signal, a second sync signal reproducing section connected to this input terminal, and a second Spatial frequency filter, a third thinning control section connected to the output terminal of the second spatial frequency filter, and a second selection switch for switching between the input video signal and the output signal of the third thinning control section. , A third frame memory connected to the output terminal of the second selection switch, a second frame synchronization circuit for controlling the third frame memory, and output signals of the first and second double speed conversion units. Selection switch for switching the output signal of the frame memory and the frame memory, a parent screen child screen switching control unit for controlling the fourth selection switch, and a video signal output terminal connected to the output terminal of the fourth selection switch. Child, third and fourth synchronization signal generators, fifth selection switch for switching output signals of the third and fourth synchronization signal generators, and deflection connected to output terminals of the fifth selection switch The pulse output terminal and the first, second, third,
This is provided with a configuration called a parent screen selection signal generator that controls the fifth selection switch.

Operation The present invention has the above-described configuration. (1) Simultaneously displays two different video signals so that one screen is a standard NTSC video signal and the other screen is a high-definition television signal. it can. (2) Further, the sub-picture is not disturbed even if the sync signal of the parent-picture is disturbed.

Embodiment A dual-screen television according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of a dual-screen television according to the first embodiment of the present invention. In the figure, 1 is a standard NTSC video signal input terminal, 2 is a first synchronizing signal reproducing circuit, 3 is a scanning line interpolating circuit, 6 is a first spatial frequency filter, 7 and 8 are first and first 2 thinning control section, 9 and 10 first and second frame memories, 11 first frame synchronization circuit, 14 and 15 first and second double speed conversion section, 29 main screen video signal And a sub-screen video signal switching switch, 30 a main-screen sub-screen switching control unit, and 31 an output terminal for a combined video signal. The above is the same as FIG. 4 described in the conventional example.

Reference numerals 4 and 5 denote first and second time axis compression circuits, which compress the time axis of the standard NTSC video signal to 3/4. Reference numeral 21 is an input terminal for a high-definition television signal, and 22 is a second synchronizing signal reproducing circuit, which reproduces vertical and horizontal synchronizing pulses and a clock. A second spatial frequency filter 23 reduces the aliasing component due to thinning. Reference numeral 24 is a third thinning control section. Reference numeral 25 is a third frame memory, and 26 is a second frame synchronization circuit for controlling writing and reading of the frame memory 25. Reference numerals 12, 13 and 27 are selection switches for switching which screen (main screen or sub screen) the input video signal is displayed. Reference numeral 28 is a parent screen selection signal generator for controlling the selection switches 12, 13, 27. Reference numeral 43 is a selection switch for switching a deflection pulse between a pulse reproduced from a standard NISC system signal and a pulse reproduced from a high-definition television signal, and is controlled by the master screen selection signal generator 28. Reference numeral 44 is a deflection pulse output terminal. The operation of the dual-screen television configured as described above will be described below. FIG. 3 is a schematic diagram of a dual-screen television.
FIG. 3a shows a high-definition television signal projected on the main screen,
This is the case of displaying the standard NTSC system on the inset screen. At this time, the selection switches 12, 13, 27, 43 are tilted to the A side, and the deflection is performed based on the synchronizing signal of the high definition television signal. In addition, the child screen is thinned out so that the aspect ratio becomes 3: 4 so that the picture becomes a natural picture. At this time, the high frequency component is cut off through the spatial frequency filter 6 so that the image quality deterioration due to the aliasing does not occur. On the other hand, when a standard NTSC video signal is displayed on the main screen and a high-definition television signal is displayed on the sub screen (3rd
In FIG. B), the selection switches 12, 13, 27 and 43 are tilted to the B side, and the deflection is performed based on the standard NTSC system video synchronizing signal. The standard NTSC video signal, which is the main screen, is time-compressed to 3/4 by the time axis compression circuits 4 and 5 so that the aspect ratio of 9 to 16 is displayed on the screen in the aspect ratio of 3: 4. The high-definition television signal serving as a child screen is thinned out so that the aspect ratio becomes 9:16 through the spatial frequency filter 23 so that aliasing does not occur.

As described above, according to the present embodiment, the standard NTSC video signal and the high-definition television signal input terminals 1 and 21 are provided, respectively, and thinned video signals for the sub-screen are created. By providing a switch that switches between displaying the main signal of the video signal on the main screen and displaying the rest of the signal on the sub screen, two standard video signals of standard NTSC and high-definition television signals can be displayed simultaneously. It is possible to realize a dual-screen television that can be used.

The second embodiment of the present invention will be described below. FIG. 2 is a block diagram of a dual-screen television showing a second embodiment of the present invention. In the figure, 1 is an input terminal for a standard NTSC video signal, 2 is a first synchronizing signal reproducing circuit, 3 is a scanning line interpolating circuit, 4,5 are first and second time axis compression circuits, and 6 is First
Spatial frequency filters, 7 and 8 are first and second thinning control units,
9, 10 are first and second frame memories, 11 is a first frame synchronization circuit, 14 and 15 are first and second double speed converters, 21
Is a high-definition television signal input terminal, 22 is a second synchronizing signal reproducing circuit, 23 is a second spatial frequency filter, and 24 is a third
Thinning control unit, 25 is a third frame memory, 26 is a second frame synchronization circuit, 12, 13, 27, 43, 29 are selection switches, 28 is a parent screen selection signal generator, and 30 is a parent screen child. The screen switching control unit, 31 is a video signal output terminal, and 44 is a deflection pulse output terminal. The above is the same as the configuration of FIG. The difference from the configuration of FIG. 1 is that third and fourth synchronizing signal generators 41 and 42 are provided.

The operation of the dual-screen television configured as described above will be described below. The third synchronizing signal generator 41 is a standard NT
Generates a sync signal (number of scanning lines: 525 lines / field frequency: 60Hz / sequential scanning) that doubles the speed of the sync signal according to the SC method, and the fourth sync signal generator 42 conforms to a high-definition television signal. Sync signal (number of scanning lines: 1125 / field frequency: 60 Hz / interlaced scanning). In the case of FIG. 3A, the selection switches 12, 13, 27, 43 are connected to the A side, and the high-definition television signal serving as the main screen is the input video synchronization signal and the output signal of the selection switch 43. Second input
Writing to the third frame memory 25 is controlled by the frame synchronization circuit 26. The reading of the third frame memory 25 is performed based on the output signal of the selection switch 43. In addition, the standard NTSC video signal that serves as the child screen is the input video sync signal and the selection switch 43
And the output signal of the parent screen / child screen switching control unit 30 are input, the first frame synchronization circuit 11 controls the writing to the first and second frame memories 9 and 10, and the reading is This is performed based on the output signal of the selection switch 43. On the other hand, in the case of FIG. 3b, the selection switches 12,1
Connect 3,27,43 to B side and perform the same operation.

As described above, according to the present embodiment, by providing the third and fourth synchronizing signal generators 41 and 42 and using the output signals for the frame synchronizing circuits 11 and 26 and the deflection pulse, the parent screen Even if the sync signal is disturbed, the sub-picture can be displayed without being disturbed.

EFFECTS OF THE INVENTION As described above, the present invention provides (1) a standard NTSC video signal input terminal, a first synchronizing signal reproducing circuit, a scanning line interpolating circuit, and first and second time-axis compression circuits. Circuit, first spatial frequency filter, first and second decimation control section, first and second frame memories, first frame synchronization circuit, first and second double speed conversion section A high-definition television signal input terminal, a second sync signal reproducing circuit, a second spatial frequency filter, a third decimation controller, a third frame memory, and a second frame synchronization. Circuit, first,
Second and fifth selection switches, a parent screen selection signal generator,
By providing a fourth selection switch, a parent screen / child screen switching control section, a video signal output terminal, and a deflection pulse output terminal, two standard NTSC system signals and two different high-definition television signals can be simultaneously transmitted. A dual-screen television that can be projected can be provided. (2) Standard NTSC video signal input terminal, first synchronizing signal reproducing circuit, scanning line interpolating circuit, first and second time axis compression circuits, first spatial frequency filter, first 1, a second decimation control unit, a high-definition television signal input terminal, a second sync signal reproduction circuit, a second spatial frequency filter, a third decimation control unit, a third, a fourth Sync signal generator, first, second, third and fifth selection switches, a parent screen selection signal generator, first and second frame memories, and a first frame synchronization circuit, First and second double speed conversion units, a third frame memory, a second frame synchronization circuit, a fourth selection switch, a parent screen / child screen switching control unit, an output terminal for video signals, By providing a deflection pulse output terminal,
Standard NTSC system High-definition television signals of two different systems can be displayed at the same time, and even if the sync signal of the parent screen video signal is disturbed or lost, the image on the child screen will not be disturbed.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a dual-screen television according to a first embodiment of the present invention, FIG. 2 is a block diagram of a dual-screen television according to a second embodiment of the present invention, and FIG. Is a schematic diagram for explaining the first and second operations, FIG. 4 is a block diagram of an example of a conventional dual-screen television, and FIG. 5 is a timing diagram for explaining the operations of FIG. 1 …… Standard NTSC video signal input terminal, 2 …… First
Synchronous signal reproduction circuit, 3 ... Scan line interpolation circuit, 4, 5 ...
First and second time axis compression circuits, 6 ... First spatial frequency filter, 7,8 ... First and second decimation control units, 9,10 ... First,
2nd frame memory, 11 ... 1st frame synchronization circuit, 14, 15 ... 1st, 2nd double speed conversion part, 21 ... high-definition television signal input terminal, 22 ... 2nd Synchronous signal reproducing circuit, 23 ... second spatial frequency filter, 24 ... third decimation control section, 25 ... third frame memory, 26
...... Second frame synchronization circuit, 12,13,27,43 ……
1st, 2nd, 3rd, 5th selection switches, 28 ... Main screen selection signal generator, 29 ... Fourth selection switch, 30 ... Main screen / Child screen switching control unit, 31 ... Video signal Output terminal, 41,4
2 …… Third and fourth synchronization signal generators, 44 …… Deflection pulse output terminal.

Claims (2)

[Claims] 1. A standard NTSC system video signal input terminal, a first synchronizing signal reproducing circuit connected to the input terminal, a first time base compression circuit, a scanning line interpolation circuit, and a first line. A spatial frequency filter, a second time axis compression circuit connected to the output terminal of the scanning line interpolation circuit, and first and second decimation control units connected to the output terminal of the first spatial frequency filter , First and second frame memories respectively connected to the output terminals of the first and second thinning-out control units, and a first frame synchronization circuit for controlling the first and second frame memories, A first selection switch for switching between an output signal of a first time base compression circuit and an output signal of the first frame memory, an output signal of the second time base compression circuit, and an output signal of the second frame memory. A second selection switch for switching between First and second double speed converters respectively connected to the output terminals of the first and second selection switches, an input terminal of a high-definition television signal, and a second synchronizing signal reproducing circuit connected to the input terminals. A second spatial frequency filter, a third decimation control unit connected to the output terminal of the second spatial frequency filter, and a third frame connected to the output terminal of the third decimation control unit. A memory; a second frame synchronization circuit for controlling the third frame memory; a third selection switch for switching an input video signal and an output signal of the third frame memory; A fourth selection switch for switching between the output signal of the double speed conversion unit and the output signal of the third selection switch;
Of the main screen and sub-screen for controlling the selection switch of the second selection switch, the video signal output terminal connected to the output terminal of the fourth selection switch, and the output pulse of the first and second synchronization signal reproduction circuits. A fifth selection switch, a deflection pulse output terminal connected to the output terminal of the fifth selection switch, and a parent screen selection signal generator for controlling the first, second, third, and fifth selection switches. A dual-screen TV that is equipped with a device. 2. A standard NTSC system video signal input terminal, a first synchronizing signal generating circuit connected to the input terminal, a first time base compression circuit, a scanning line interpolation circuit, and a first line. A spatial frequency filter, a second time axis compression circuit connected to the output terminal of the scanning line interpolation circuit, and first and second decimation control units connected to the output terminal of the first spatial frequency filter A first selection switch for switching the output signal of the first time-base compression circuit and the output signal of the first thinning-out control unit, and the output signal of the second time-base compression circuit and the second thinning-out control unit. A second selection switch for switching an output signal, first and second frame memories respectively connected to the output terminals of the first and second selection switches, and controlling the first and second frame memories The first frame synchronization circuit and the first and second frames First and second double speed converters respectively connected to the output terminals of the memory, a high-definition television signal input terminal, a second sync signal reproducing section connected to the input terminal, and a second space. Frequency filter and a third spatial frequency filter connected to the output terminal of the second spatial frequency filter
A thinning-out control unit, a third selection switch for switching between an input video signal and an output signal of the third thinning-out control unit,
A third frame memory connected to the output terminal of the third selection switch; a second frame synchronization circuit for controlling the third frame memory;
A fourth selection switch for switching the output signal of the double speed conversion unit and the third frame memory output signal, and a parent screen / child screen switching control unit for controlling the fourth selection switch,
The video signal output terminal connected to the output terminal of the fourth selection switch, the third and fourth synchronization signal generators, and
3, Fifth switching output pulse of the fourth synchronization signal generator
Selection switch, the deflection pulse output terminal connected to the output terminal of the fifth selection switch, and the first, second, and
A dual-screen television comprising a main screen selection signal generator for controlling the third and fifth selection switches.