JPH0514761A - Color television receiver - Google Patents

Abstract

PURPOSE:To enable the interlace display of a slave screen by using a synchronizing pulse from a synchronizing signal generating circuit for the slave screen for a clock for the slave screen at the time of a non-interlace display by a master screen. CONSTITUTION:At the time of the non-interlace display such as a character display by the master screen, a character decoder 7 prepares the horizontal and vertical synchronizing pulses of the non-interlace by the incorporated synchronizing signal generating circuit. Then, this pulse is used for the display of the master screen, and the horizontal and vertical pulses outputted from a synchronizing signal generating circuit 8 for the slave screen are used for a clock for an A/D conversion, and the clock for reading a video memory 4, for preparing the slave screen. Then, the horizontal and vertical pulses are inputted through the decoder 7 to a slave screen processing circuit 3. Thus, at the time of the non-interlace display by the master screen, the interlace display by the slave screen can be operated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color television receiver having a child screen display function.

[0002]

2. Description of the Related Art In recent years, color television receivers having a sub-screen display function have come on the market, and when an image displayed on a parent device is a character image, it is displayed by a non-interlace method. Therefore, the screen of the child device is required to be displayed in an interlace system.

A conventional color television receiver having a child screen display function will be described below with reference to the drawings.

As shown in FIG. 2, the sub-screen display function is first performed by the input switching circuit 1 as an input video signal among television broadcast, satellite broadcast (abbreviated as BS), video tape recorder (abbreviated as VTR), and the like. A video signal obtained by selecting any one and demodulating and adding it to the video chroma jungle circuit 2 and the sub-screen processing circuit 3 from the video memory 4 and the character decoder (having a character synchronizing signal generating circuit) 7 Create a child screen by using. Next, the RGB matrix 5 converts the color difference signal of the small screen into three primary color signals of R, G, B and applies the signals to the small screen switching circuit 6.

The operation of the color television receiver having the child screen display function configured as described above will be described below. As shown in FIG. 2, the sub-picture luminance signal Y, the color difference signals RY and BY, the horizontal sync pulse H, and the vertical sync pulse V output from the video chroma jungle circuit 2 are used for the sub-picture processing circuit 3. In A, a screen compressed by the video memory 4 for accumulating the sub-screen compressed data after A / D conversion and digital processing is created. At this time, the A / D conversion for writing the child screen and the write clock pulse of the video memory 4 are supplied from the horizontal and vertical synchronizing pulses H _p ″, V _p ″ of the parent screen through the character decoder 7 to the voltage controlled oscillator VCO and the PLL circuit. Is created inside the sub-picture processing circuit 3. After the child screen is processed, D
The luminance signal Y'and the color difference signals RY 'and BY' of the A / A converted and compressed child screen signal are output, and the RGB matrix circuit 5 obtains the three primary color signals of R, G and B to obtain the child screen. It is added to the switching circuit 6. The small screen switching circuit 6 superimposes the small screen signal on the main screen signal to obtain a combined output signal.

[0006]

However, in the above-mentioned conventional structure, the main screen displays a non-interlaced display as in the case of a character television or a color television receiver with RGB input. In this case, since the write clock used for the A / D converter and the memory circuit of the sub-screen is made from the non-interlaced sync signal, the display screen of the sub-screen becomes non-interlaced and the vertical direction. Had the problem of half the resolution.

The present invention solves the above-mentioned conventional problems. Even when the main screen is non-interlaced,
The small screen has a small screen display function that enables interlaced display. It is an object to provide a color television receiver.

[0008]

In order to achieve the above object, a color television receiver having a sub-screen display function of the present invention has a sub-screen when the main screen is a non-interlaced display such as a character display. The clock for use is provided in addition to the sync signal for the parent screen, and a sync signal generation circuit for the child screen is provided.

[0009]

According to the present invention, with the above configuration, the main screen is a character image.
If the surface is displayed, it is included in the child screen processing circuit.
Voltage controlled oscillator VCO circuit and PLL circuit
Screen for A / D conversion circuit and video memory readout
The lock is for the child screen without using the sync signal of the parent screen signal.
Horizontal and vertical sync pulse H from sync signal generator _p′,
V_p′ Is used.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, a circuit having the same operation as that of FIG. 2 showing a circuit configuration of a conventional color television receiver having a child screen display function is given the same reference numeral and its description is omitted. The present embodiment is different from the conventional example in that a sub-screen synchronization signal generating circuit 8 is newly provided.

The operation of the color television receiver having the child screen display function configured as described above will be described with reference to FIG.

First, when the main screen displays a normal general video signal, the video signal input from the main screen to the character decoder 7 and the horizontal and vertical pulses H _p ″, V _p ″.
Passes through the character decoder 7 and enters the small screen processing circuit 3 as it is, and the VCO circuit and the PL in the small screen processing circuit 3 are connected.
It is used by the L circuit as an A / D conversion circuit of the child screen and a read clock of the video memory 4.

Next, when the main screen receives a character broadcast or the like and displays a non-interlaced screen, the character decoder 7 uses the built-in sync signal generation circuit to perform non-interlaced horizontal and vertical sync pulses. It makes H _p and V _p . To display the parent screen, H _p and V _p as they are may be used. However, the A / D conversion clock for creating the child screen and the reading clock of the video memory 4 are used as the horizontal and vertical synchronizing pulses H _p and V _p for the characters on the parent screen display.
When the child screen is created, the data of the 1-field screen is lost. Therefore, in the present embodiment, the horizontal signal output from the newly-provided sub-screen synchronization signal generation circuit 8
The vertical pulses H _p ′ and V _p ′ are passed through the character decoder 7 and
Input to the small screen processing circuit 3.

As a result, even when the main screen is displayed in the non-interlace mode, the interlaced display is maintained in the slave screen, and the screen data of one field is not lost.

[0016]

As described above, in the color television receiver having the child screen display function of the present invention, the child screen is interlaced even if the parent screen is a non-interlaced screen display such as when receiving a character broadcast. It is possible to realize a color television receiver that can be displayed and does not deteriorate the vertical resolution of the small screen and has an excellent small screen display function.

[Brief description of drawings]

FIG. 1 is a block diagram of a color television receiver having a child screen display function according to an embodiment of the present invention.

FIG. 2 is a block diagram of a conventional color television receiver with a small screen display function.

[Explanation of symbols]

3 Child screen processing circuit 4 video memory 6 Sub screen switching circuit 7 character decoder 8 Sub-screen sync signal generation circuit

Claims (2)

[Claims] 1. A non-interlace sync signal generator for receiving and displaying a teletext and an interlace sync signal generator for superimposing and displaying a sub-screen on a main screen are built-in. A color television receiver having a sub-screen display function for switching to the synchronization signal to display a screen. 2. A teletext reception screen is displayed on the entire screen in a non-interlaced manner, and the sub-screen display is switched to an interlaced sync signal generator for the sub-screen display, or when the sub-screen is not displayed. , The non-interlaced synchronizing signal for teletext is switched to.
Color television receiver as described.