JPH0585172U - Television receiver - Google Patents

Abstract

(57) [Summary] [Purpose] Even when a teletext decoder dedicated to the vertical sync signal of 50 Hz is used, it is possible to always display arbitrary characters and the like regardless of the vertical sync signal. In a television receiver capable of receiving television broadcasting systems having different vertical frequencies and having a character multiplex broadcasting decoder, character data is extracted from a television signal by a data slicer 13, and a text decoder 14 is used.
The frequency discriminating circuit has a text mode in which a character display signal is displayed on the CRT 21 and an arbitrary character display mode in which the operator can arbitrarily display characters on the CRT 21 using the text decoder 14, and the vertical frequency is 60 Hz. 16, and when the arbitrary character display mode is selected, the transistor 12 is turned on by the H signal from the channel selection microcomputer 9 so that the vertical timing of the display timing signal from the teletext decoder 14 becomes 50 Hz. .

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a television receiver with a built-in teletext broadcasting system decoder (hereinafter referred to as a teletext decoder) for receiving British character multiplex broadcasting.

[0002]

[Prior Art]

 Conventionally, a television receiver with a built-in teletext decoder has a mode for receiving and displaying normal television broadcasting (hereinafter referred to as TV mode) and a mode for receiving and displaying teletext broadcasting (hereinafter referred to as text mode). ) And.

Then, when the TV mode is selected, the television signal of the reception channel is demodulated by the television signal processing circuit and converted into a screen display signal such as a three primary color signal (RGB signal). It is supplied to a display device such as a CRT and a normal television program is displayed on the screen.

When the text mode is selected, the display data of the character multiplex broadcast of the receiving channel is extracted by the character decoder and converted into a screen display signal, and the character broadcast number is displayed on the screen.

As described above, in this type of television receiver, the character data, the numerical data, etc. transmitted by the character multiplex broadcasting are displayed as the characters, the numerical characters, etc. on the CRT screen.

Therefore, the applicant of the present invention has proposed a television receiver capable of inputting one's own message or the like on the CRT by using the character and number display function as shown in FIG. 4 and displaying the message on the CRT at any time. It is proposed in Japanese Patent Application No. 3-28792.

By the way, there are three types of television broadcasting systems in the world, that is, NTSC system, PAL system and SECAM system, and there are differences in the number of scanning lines and vertical frequency depending on each broadcasting system. Television receivers that can receive all different broadcasting systems have also been developed.

On the other hand, in Europe, teletext broadcasting is carried out in the United Kingdom, and the television broadcasting system is the PAL system in the United Kingdom. Therefore, the specification of the teletext decoder for receiving the British teletext broadcasting is in conformity with the PAL system, and the vertical frequency is 50 Hz in order to synchronize the display on the CRT and the character display.

Therefore, when this teletext decoder is dedicated to the vertical sync signal of 50 Hz, vertical sync cannot be obtained when a broadcast of the vertical sync signal of 60 Hz is received, and the teletext decoder also serves as a character display function at 60 Hz. , The screen display when displaying characters is disturbed. In addition, there is a drawback that it becomes inconvenient because it is limited only when the vertical synchronizing signal of 50 Hz is received.

[0010]

[Problems to be solved by the device]

 The present invention enhances added value by being able to always display arbitrary characters, numbers and symbols without distinction between vertical sync signals of 50 Hz and 60 Hz even when a teletext decoder dedicated to vertical sync signals of 50 Hz is used. , It is intended to improve the usability of the user.

[0011]

[Means for Solving the Problems]

 The present invention, in a television receiver equipped with a teletext decoder, has an operation section that can specify a channel selection mode, an arbitrary text display mode, and a text broadcast reception mode by key operation, and a specification from the operation section. A tuning control unit that supplies a desired tuning voltage, commands arbitrary character display, and commands to receive teletext, a display character signal corresponding to the character data of the teletext signal, and the above-mentioned tuning. A character generator for generating a display character signal according to the designation of an arbitrary character display from the control section, and a means for generating a synchronization signal having a predetermined frequency for generating a timing signal for displaying the display character signal. , A vertical frequency discriminating means for discriminating a difference in vertical frequency, and an output obtained from the vertical frequency discriminating means in an arbitrary character display mode. A television receiver characterized by outputting a display character signal designated in an arbitrary character display mode at the timing of the frequency of the synchronizing signal generating means when the frequency is different from that of the timing signal generated by the synchronizing signal generating means. Is a machine.

[0012]

[Action]

 When the teletext decoder dedicated to the vertical sync signal of 50 Hz is used, the H signal is output from the tuning microcomputer based on the signal obtained from the field frequency discrimination circuit when the broadcast of the vertical sync signal of 60 Hz is received. Then, the switching transistor is turned on, and the composite signal is not input to the teletext decoder. In this state, the teletext decoder automatically outputs the synchronizing signal oscillated inside the teletext decoder. Therefore, even if a broadcast with a vertical synchronizing signal of 60 Hz is received, vertical synchronization cannot be achieved and the screen display is not disturbed.

[0013]

【Example】

 An embodiment of the present invention will be described with reference to FIGS. 1, 2 and 3. First, in FIG. 1, 1 is an antenna, 2 is a tuner, 3 is a VIF / SIF signal processing circuit, 4 is an AV switching circuit, 5 is an audio signal amplifying circuit, 6 is a speaker, 7 is a remote control transmitter, and 8 is a remote controller. A receiving unit for receiving a signal, 10 is a nonvolatile memory for storing tuning data, 12 is a switching transistor, and 16 is a frequency discriminating circuit for discriminating a vertical frequency.

Reference numeral 9 denotes a channel selection microcomputer which supplies a tuning signal to the tuner 2 in response to a signal from the remote controller 7, switching control of the AV switching circuit 4, mute control of the audio signal amplification circuit 5, and VIF / VIF / The SIF signal processing circuit 3 is controlled. At the same time, it controls the text decoder 14 described later.

Reference numeral 11 is a text microcomputer, which controls the output of the character multiplex broadcasting signal according to a command from the channel selection microcomputer 9. A data slicer 13 extracts character signal data from the video signal. An S-RAM (static-random access memory) 15 stores the character data obtained by the data slicer 13. Reference numeral 14 is a text decoder, and as shown in FIG. 2, a sync separation circuit 24, a character generator 25, a timing signal generator 30, a clock generator 29, a sync signal detector 27, a switch 25, and a data latch 28. It consists of

The text decoder having such a structure can be composed of, for example, an IC manufactured by Philips with product numbers SAA5231 and SAA5243.

Reference numeral 17 is a signal processing circuit for processing the video signal obtained by the AV switching circuit 4, 18 is a horizontal deflection circuit, 19 is a vertical deflection circuit, 20 is an RGB output circuit, and 21 is a CRT (cathode ray tube). ), 22 and 23 are external input terminals.

Next, the operation will be described. First, the case of the television mode will be described. In the television mode, the video signal from the tuner 2 and the video signals from the external terminals 22 and 23 are selected by the AV switching circuit 4 and then input to the data slicer 13. The character signal data is extracted by the data slicer 13 and input to the text decoder 14. However, the video signal is also input to the signal processing circuit 17, and the video signal is displayed on the CRT 21.

A character generator (not shown) is built in the channel selection microcomputer 9, and when a channel display is designated, the character generator outputs the character to the RGB output circuit 20 and the CRT 21. Channel is displayed.

Second, the text mode will be described. The video signal processed by the VIF / SIF processing circuit 4 is input to the data slicer 13 to extract character signal data, and the character signal data is input to the text decoder 14. At the same time, the composite sync signal is also extracted in order to set the display timing of the CRT 21 of the character signal.

The operation of the text decoder 14 will be described in detail with reference to FIG. First, the character signal data is latched by the data latch 28 and then stored in the S-RAM 15. On the other hand, the sync separation circuit 24 extracts the composite sync signal, thereby causing the clock generator 29 to generate a 6 MHz clock with the horizontal sync signal.

The timing signal generator 30 inputs various timing signals such as writing and reading data to and from the S-RAM 15 and outputting the character generator 25. As one of them, the composite synchronizing signal is generated from the timing signal generating circuit 30. On the other hand, in the text mode, the separated sync signal is also output from the sync separation circuit 24. In the text mode, the sync detection circuit 27 detects the composite sync signal and switches the switch 26. And outputs the composite sync signal to the signal processing circuit 16 for the timing of character display.

Therefore, when the text mode is set by the operator's designation, the character data of the video signal is extracted by the data slicer 13, and the data is input to the text decoder 14 and stored in the S-RAM 15. Then, the data is read from the S-RAM 15 and the character generator 25 is controlled so as to generate a character signal corresponding to the data to output RGB signals and display the character signals on the CRT 21.

Thirdly, the arbitrary character display mode will be described. This mode is a function that allows the operator to display arbitrary characters on the CRT 21 by using the character signal generation function of the text decoder.

Next, the operation will be described. The video signal processed by the VIF / SIF processing circuit 4 is input to the data slicer 13 that extracts text data. Then, the data slicer 13 extracts the composite synchronizing signal and synchronizes with the timing signal generator 30 of the text decoder 14 based on this signal. At this time, in the case of the arbitrary character display mode, the tuning microcomputer 9 controls the text microcomputer 11 so that the character designated by the operator is displayed from the remote controller 7, and the text microcomputer 11 controls the character generator 25 of the text decoder 14. ..

Then, RGB signals are output in synchronization with the video signal processed by the VIF / SIF processing circuit 4, and characters are displayed on the CRT 21.

By the way, this text decoder is adapted to the British teletext system. Therefore, the text decoder is also adapted to the television broadcasting system, and the timing signal generator 30 is also adapted to the frequency of the composite synchronizing signal. In the case of this text decoder, the vertical frequency is set to 50 Hz.

Therefore, when the broadcast of the vertical synchronizing signal 60 Hz is received, the timing signal generator 30 of the text decoder 14 cannot be synchronized, and is synchronized with the video signal processed by the VIF / SIF processing circuit 4. Since RGB signals that are not output are output from the character generator 25, the display is disturbed.

However, when the composite sync signal is not input to the text decoder 14, the timing signal generator 30 is in the free-run state because it is not affected by the vertical sync signal input from the data slicer 13, and the vertical sync signal of 50 Hz is input. Is configured to output.

Therefore, according to the present invention, the information discriminated by the field frequency discriminating circuit 16 is input to the tuning microcomputer 9, and the tuning microcomputer 9 judges as shown in FIG. Output H from 9. Then, the switching transistor 12 is turned on, and the input terminal of the data slicer 13 is grounded. By doing so, the timing signal generator 30 of the text decoder 14 is in the free-run state without being affected by the video signal processed by the VIF / SIF processing circuit 4, and outputs the composite sync signal including the vertical sync signal of 50 Hz. .. And it is possible to display synchronized arbitrary characters.

[0031]

[Effect of the device]

 According to the present invention, the screen display can be synchronized even if the broadcast of the vertical synchronizing signal of 60 Hz is received, and the screen display can be performed by the teletext decoder at any time, which is convenient for the user. Can be improved.

[Brief description of drawings]

FIG. 1 is an embodiment of the present invention.

FIG. 2 is a diagram for explaining an embodiment of the present invention.

FIG. 3 is a flow chart for explaining the operation of the embodiment of the present invention.

FIG. 4 is a diagram showing an example of display in an arbitrary character display mode.

[Explanation of symbols]

 7 Remote Control Transmitter 8 Remote Control Receiver 9 Tuning Microcomputer 10 Nonvolatile Memory 11 Text Microcomputer 12 Switching Transistor 13 Data Slicer 14 Text Decoder 15 S-RAM 16 Vertical Frequency Discrimination Circuit

Claims (1)

[Scope of utility model registration request] 1. In a television receiver equipped with a teletext decoder, an operation section capable of designating a channel selection mode and an arbitrary text display mode or teletext reception mode by a key operation or the like, and a designation from the operation section. A tuning control unit that supplies a desired tuning voltage, commands arbitrary character display, and commands to receive a character broadcast, a display character signal corresponding to character data of a character broadcast signal, and the above-mentioned channel selection. A character generator for generating a display character signal according to designation of arbitrary character display from the control unit, a means for generating a synchronizing signal of a predetermined frequency for generating a timing signal for displaying the display character signal, and a vertical frequency The vertical frequency discriminating means for discriminating the difference between the vertical frequency discriminating means A television receiver characterized by outputting a display character signal designated in an arbitrary character display mode at the timing of the frequency of the synchronizing signal generating means when the frequency is different from that of the timing signal generated by the synchronizing signal generating means. .