JPS63189086A - Television receiver - Google Patents

Abstract

PURPOSE:To prevent the deterioration of picture quality by the excessive emphasis of the contour by discriminating the reception display of teletext among signals outputted from a character decoder part which is incorporated to receive the teletext and stopping the operation in a contour correction part. CONSTITUTION:A back switch signal is generated by the character signal decoder part incorporated in the receiving adaptor of the teletext according to an area where the character is super-displayed and supplied to an RGB signal switch circuit 6. The super-display character is facilitated to be seen by reducing back brightness. A television character screen switch signal Y and a back brightness switch signal Y are inputted by an OR gate 10 composing the contour correction interruption control part 9 and a correction interruption signal is outputted while one of those signals is generated. Thus a switch circuit 13 provided with the contour correction part 11 is operated to earth all velocity modulation signals from a velocity modulation signal generation circuit 12 and the contour correction part 11 is stopped operating.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a television receiver having an outline correction function for emphasizing the outline of a displayed image and a teletext receiving function.

[Conventional technology]

2. Description of the Related Art In recent years, with the rapid development of electronic technology and semiconductor integration technology, there is a tendency for various functions to be added to television receivers. These additional functions include a contour correction function and a teletext broadcast reception function.

Here, the contour correction function extracts a signal indicating the contour part of the image from the video signal, and uses a speed modulation signal obtained by differentiating this signal to speed-modulate the horizontal deflection of the electron beam in the cathode ray tube, thereby creating a display image. By emphasizing the outline of the image, the displayed image becomes sharper.

Further, the teletext multiplexing reception function extracts character signals that are multiplexed and sent during a predetermined horizontal retrace period and displays them as a character screen or superimposes them on a television screen.

[Problem that the invention seeks to solve]

However, when receiving and displaying a teletext broadcast on a television receiver that has an outline correction function, the outline correction function also acts on the character display screen, so the outline of the character screen is overemphasized. This has the problem that the screen becomes difficult to view.

[Means for solving problems]

The television receiver according to the present invention determines the reception indication of teletext broadcasting from the signal output from the character decoder section which is built in or built into an adapter and connected via a connector in order to receive teletext broadcasting. A contour correction stop control section is provided for stopping the operation of the contour correction section.

[Effect]

In a television receiver configured in this way,
Since contour correction for a character screen that receives teletext is automatically stopped, both the television screen and the character screen can be easily viewed.

[Embodiments of the invention]

FIG. 1 is a block diagram of essential parts showing an embodiment of a television receiver according to the present invention. In the figure, 1 is a tuner circuit that selects and extracts only a target television broadcast signal from signals supplied from an antenna (not shown). 2 is a video intermediate frequency amplification circuit for amplifying the output signal of the tuner circuit l; 3 is a 21-pin type connector to which a teletext broadcast receiving adapter (not shown) is connected; and 3a is a video intermediate frequency amplification circuit 4 supplied from the video intermediate frequency amplification circuit 3b is a terminal to which a video signal is supplied from the teletext broadcasting reception adapter; 3c is a terminal to which a switching signal is supplied;
3d to 3f are terminals to which RGB (three primary color) signals are supplied;
3g is a terminal to which a television/character screen switching signal Y is supplied, and 3h is a terminal to which a back luminance switching signal YM is supplied. Reference numeral 4 denotes a video signal switching circuit which selects the video signal supplied from the video intermediate frequency amplification circuit 4 and the video signal supplied from the outside via the terminal 3b of the connector 3 in accordance with the switching signal, and converts the video signal into a video signal. It is supplied to the chroma circuit 5. Reference numeral 6 denotes an R-CB signal selection circuit which selects an RGB signal supplied from the video chroma circuit 5 and an RGB signal supplied from a teletext receiving adapter (not shown) and supplies the selected RGB signal to the video output circuit 7. This RGB signal selection circuit 6 is
When the TV/character screen switching signal Y supplied via the terminal 3g of the connector 3 is at the L level, the ROB signal supplied from the video chroma circuit 5 is selected, and the TV/text screen switching signal Y is at the H level. Sometimes, it selects and outputs RGB signals supplied from a teletext receiving adapter. 7 is a video output circuit connected to the RGB signal selection circuit 6, and 8 is a cathode ray tube for displaying the output of the video output circuit 7.

Reference numeral 9 denotes a contour correction stop control unit which determines the reception status of a teletext broadcast from a signal supplied from a teletext reception adapter (not shown) and outputs a correction stop signal, and is built in the teletext reception adapter. Connector 3 terminals 3g, 3. , h, and an OR gate 10 which calculates the logical sum of the television/character screen switching signal Ys and the back brightness switching signal YM supplied through the terminals 1 and 2. Reference numeral 11 denotes an outline correction unit that emphasizes the outline of the displayed image, which extracts a signal indicating the outline of the image from the video signal supplied from the video signal switching circuit 4, differentiates this signal, and generates a speed modulation signal. A speed modulation signal generation circuit 12 that generates a speed modulation signal, and a switch circuit 1 that turns on and off the speed modulation signal output from the speed modulation signal generation circuit 12.
3, and a speed modulation drive circuit l4 that drives the speed modulation coil 15 attached to the neck portion of the cathode ray tube 8 according to the speed modulation signal supplied via the switch circuit 13.
It is composed of. In this case, the switch circuit 13 supplies the speed modulation signal generated from the speed modulation signal generation circuit 12 to the speed modulation drive circuit 14 in the normal state, and supplies the correction stop signal from the contour correction stop control section 9. Then, the speed modulation signal generation circuit 12
The configuration is such that the speed modulation signal generated from the contour correction section 11 is bypassed to ground, and the operation of the contour correction section 11 is stopped.

In the television receiver configured in this manner, the tuner circuit 1 selects and outputs a designated television broadcast signal from signals supplied from an antenna (not shown),
The video intermediate frequency amplification circuit 2 amplifies the television broadcast signal output from the tuner circuit 1 and converts it into a video signal switching circuit 4.
supply to.

Here, in the state of receiving television broadcasting, the teletext broadcasting receiving adapter is inoperative, and therefore no switching signal is supplied. As a result, the video signal switching circuit 4
selects the video signal supplied from the video intermediate frequency amplification circuit 2 and supplies it to the video chroma circuit 5.

In addition, when the teletext receiving adapter (not shown) connected to the connector 3 is not in operation, the TV/text screen switching signal Y is at the L level, so the RGB signal switching circuit 6 switches the video chroma The RGB signals supplied from the circuit 5 are selected and supplied to seven video output circuits. The video output circuit 7 displays the received image by driving the cathode ray tube 8 according to the RGB signal supplied from the RGB signal switching circuit 6.

On the other hand, since both the TV/text screen switching signal Y and the back brightness switching signal YM supplied from the teletext decoder section of the teletext receiving adapter (not shown) via the connector 3 are at L level, The correction stop signal output from the OR gate 10 constituting the correction stop control section 9 is at L level, rendering the switch circuit 13 inactive.

Here, when the video signal selected by the video signal switching circuit 4 is supplied to the contour correction section 11, the speed modulation signal generation circuit 12 first detects the high frequency component of the video signal and differentiates this signal. By doing this, a limbal signal corresponding to the contour part of the image is extracted. Then, this speed modulation signal is in a non-operating state, and the switch circuit 1 which allows the signal to pass through.
3 to the speed modulation drive circuit 14. When the speed modulation drive circuit 14 receives the speed modulation signal,
A current corresponding to this speed modulation signal is supplied to the speed modulation coil 15. Here, since the speed modulation coil 15 is arranged so that the magnetic field generated by it influences the horizontal deflection speed of the electron beam in the cathode ray tube 8, the horizontal deflection speed is modulated according to the speed modulation signal. become. Here, since the velocity modulation signal corresponds to the contour portion of the image, a portion of the phosphor film at the contour portion of the displayed image is increased in stimulation by the electron beam. As a result,
The brightness at the outline of the displayed image increases, resulting in a sharp image.

Next, when the teletext receiving adapter (not shown) connected to the connector 3 is powered on and set to the teletext receiving mode, the teletext receiving adapter connects the video intermediate frequency amplification circuit 2 to the connector 3. A video signal received from a television broadcast supplied through the terminal 3a of the terminal 3a is taken in. Then, the teletext multiplex reception adapter extracts the character signal multiplexed and sent during the horizontal retrace period of the video signal, and converts it into an RGB signal by decoding it with a built-in character signal decoder section. The RC and B signals for character display taken out in this way are connected to the terminals 3d to 3r of the connector 3.
The signal is supplied to the RGB signal switching circuit 6 via the RGB signal switching circuit 6. Further, the character signal decoder section built into the teletext broadcasting receiving adapter sets the television/text screen switching signal Y to H level when sending out the RGB signal as the character display signal. As a result, the RGB signal switching circuit 6 receives the RGB signals supplied from the teletext receiving adapter via the connector 3 when the TV/text screen switching signal Y is generated.
A signal is selected and supplied to the video output circuit 7. in this case,
Teletext reception adapter.

Since the RGB signal supplied from the computer is a character ↑ video signal that is multiplexed and sent during the horizontal retrace period of television transmission, the cathode ray tube 8 displays characters corresponding to the character information on the television. This will be superimposed on, for example, the lower part of the John broadcast reception screen. In addition, the character signal decoder built into the teletext receiving adapter generates a back brightness switching signal corresponding to the horizontal deflection period for the area where characters are superimposed, and converts this back brightness switching signal into RGB signal switching. Supplied to circuit 6. RG
When the B signal switching circuit 6 receives the back brightness switching signal, it lowers the back brightness during the period to make the superimposed characters easier to see.

Here, the OR gate 1 constituting the contour correction stop control section 9
0 inputs the TV/character screen switching signal Y and the back brightness switching signal Y, so the period during which either of these signals is generated, that is, the area where the received characters of the teletext broadcast are displayed, is horizontal. A correction stop signal will be sent during the deflection period. When this correction stop signal is generated, the switch circuit 13 provided in the contour correction section 11 is activated, and the speed modulation signal generation circuit 12 is activated.
The operation of the contour correction section 11 is stopped by bypassing all the velocity modulation signals generated from the contour correction section 11 to ground.

In other words, the outline emphasizing process for the area where the characters are superimposed is stopped, and the outlines of the characters are automatically prevented from being overemphasized and even visible.

FIG. 2 is a circuit diagram showing a specific example of the speed modulation signal generation circuit 12 and the switch circuit 13 shown in FIG.
7 amplifies the video signal. The low frequency component of this amplified video signal is grounded by the inductance 18, whereby a high frequency component signal corresponding to the outline of the displayed image is extracted. This wide-range component signal is differentiated by a differentiating circuit including a capacitor 19 and a resistor 20, and then sent out via a transistor 21 as a speed modulation signal. Moreover, the switch circuit 13 is
Inductance 18 in speed modulation signal generation circuit 12
A transistor 22 is connected in parallel to the correction stop signal and turned on by a correction stop signal. Here, in normal times, since the correction stop signal is at the L level, the transistor 22 is turned off and does not have any influence on the speed modulation signal generation circuit 12. On the other hand, when the correction stop signal becomes H level and the transistor 22 is turned on, the video signal amplified by the transistor 17 in the speed modulation signal generation circuit 12 is all bypassed to ground, so the speed The speed modulation signal generation operation in the modulation signal generation circuit 12 is completely stopped.

FIG. 3 is a block diagram of main parts showing another embodiment of the television receiver according to the present invention, and the same parts as in FIG. 1 are indicated using the same symbols. Here, the television receiver shown in Fig. 1 is configured to receive text broadcasting by externally connecting a text multiplex adapter, whereas the television receiver shown in Fig. 3 is configured to receive text signals by externally connecting a text multiplex adapter. A television receiver has a built-in character signal decoder section 23 that extracts character signals from multiplexed video signals and converts them into RGB signals. In this case, as in the case of the embodiment shown in FIG.
A similar operation can be obtained by controlling the operation of the contour correction section 11.

As explained above, the television receiver according to the present invention receives a teletext broadcast from a signal output from a character decoder section that is built in or built into an adapter and connected via a connector in order to receive the teletext broadcast. The operation of the contour correction section is stopped by determining the reception display of the contour correction section. Therefore, the contour correction for the character screen that has received the teletext is automatically stopped, which has the effect of preventing image quality deterioration due to excessive contour enhancement of the character screen.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of main parts showing an embodiment of the television receiver according to the present invention, FIG. 2 is a circuit diagram showing a specific example of the contour correction section shown in FIG. 1, and FIG. 3 is a television receiver according to the present invention. FIG. 2 is a block diagram of main parts showing another embodiment of the John receiver. 1...Tuner circuit, 2...Video intermediate amplification circuit, 3...Connector, 4...
Video signal switching circuit, 5...video chroma circuit,
6...RGB switching circuit, 7...Video output circuit, 8...Cathode ray tube, 9...Contour correction cancellation control unit, 10...・・Or Gate, 11・
... Contour correction section, 12 ... Speed modulation signal generation circuit, 13 ... Switch circuit, 14 ...
... Speed modulation drive circuit, 15 ... Speed modulation coil, 23 ... Character signal decoder.

Claims (3)

[Claims] (1) A contour correction unit that enhances the contour of the displayed image by modulating the horizontal deflection speed using a speed modulation signal obtained by differentiating a signal indicating the contour portion of the video extracted from the video signal, and a device for receiving teletext. In a television receiver having a character signal decoder section built into the adapter or built into the adapter and connected via a connector, reception of a teletext broadcast is determined from the signal output from the character signal decoder section, and the contour A television receiver comprising a contour correction stop control section that stops the operation of the correction section. (2) The contour correction stop control section that determines the receiving status of teletext broadcasting and stops the operation of the contour correction section is configured to control the area where the TV/text screen switching signal and text information output from the text signal decoder section are displayed. 2. The television receiver according to claim 1, further comprising an OR gate that calculates a logical sum with a background brightness switching signal that performs control to reduce background brightness. (3) The television according to claim 1, wherein the contour correction section has a switch circuit that prevents the transmission of the speed modulation signal when a correction stop signal is supplied from the contour correction stop control section. receiver.