JPS6239873B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a teletext broadcasting receiving apparatus that receives and reproduces television signals containing text information.

Characters in the vertical synchronization signal period of the television signal,
Devices have been developed that transmit symbol and graphic information in a superimposed manner while reproducing text, symbol and graphic information on the screen of television receivers. However, the above-mentioned characters, symbols, and graphic information may be distorted or drop-out during transmission or during sampling processing, and in such cases, blank portions will occur when reproduced.

This invention has been made in view of the above circumstances, and is a teletext broadcasting system that can compensate for blanks on the playback screen by inserting previous information into the dropout period when transmission data dropout occurs. The purpose is to provide a receiving device.

Embodiments of the present invention will be described below with reference to the drawings.

First, a teletext receiving system for a color television receiver according to the present invention will be explained.

The format of the television signal used in teletext broadcasting is set as shown in FIG. FIGS. 1a and 1b show vertical blanking period portions of the first field and the next field of a composite video signal, where V is a vertical synchronizing signal. Teletext packets 1 and 2 are set at the rear of this vertical retrace period, for example, at the 20th H (H: one horizontal period) after the previous field ends. The format of this teletext packet is set as shown in FIG. 1c. H is a horizontal synchronization signal, and 5 is a color burst. The teletext packet 2 is formed by a header section 6 and an information section 7. This teletext packet 2 is shown in more detail in FIG. 1d. That is, the header section 6 has a clock run-in (clock run-in).
run in) signal CRI, framing coat FC, identification eye code IDC, program code
It is composed of PC1, PC2, etc.

The clock line signal CRI is a signal for adjusting the phase of the clock pulses necessary for sampling the data in this teletext packet. The framing code FC is a code that indicates the beginning of data. Identification eye code IDC is a code for identifying display format, transmission signal format, etc. Program code PC1,
PC2 is a code indicating the type of text information program.

The teletext packets described above are processed, for example, by a system as shown in FIG. 1
Reference numeral 1 denotes an input terminal to which an intermediate frequency of a teletext television signal is input. The signal applied to this input terminal is detected by a video detection circuit 12, and the composite video signal is input to a waveform shaping circuit 13 which extracts a teletext packet and shapes the waveform. Further, the composite video signal is input to a synchronization separation circuit 21 that separates a vertical synchronization signal V and a horizontal synchronization signal H.

The vertical synchronization signal V and horizontal synchronization signal H separated from the synchronization separation circuit 21 are sent to the vertical position counter 2.
2 is input. This vertical position counter 22 is
It is reset by the vertical synchronizing signal V, and the horizontal synchronizing signal H
By counting the numbers, it is possible to obtain a sampling pulse corresponding to the position where the teletext packet is superimposed.

The sampling pulse obtained by the vertical position counter 22 is input to the waveform shaping circuit 13. As a result, the teletext packet described in FIG. 1 is extracted from the waveform shaping circuit 13 and its waveform is shaped. The output obtained from this waveform shaping circuit 13 is input to a sampling circuit 14 and also to a clock line signal detection circuit 16.

The clock line signal detection circuit 16 is shown in FIG.
The clock line signal CRI shown in FIG. This clock pulse generating circuit 17 has a function of generating continuous clock pulses in synchronization with the clock run-in signal. Continuous clock pulses output from the clock pulse generating circuit 17 are input to the sampling circuit 14 and used as data sampling pulses.

In the sampling circuit 14, various types of data as shown in FIG. The output of the sampling circuit 14 is also input to a framing code detection circuit 18.
The framing code detection circuit 18 performs detection by comparing a predetermined framing code with the input code, detects a point where the codes completely match, and sets the start of data in the buffer memory. It is something. Framing code detection circuit 18 is driven by clock pulses from horizontal position counter 23, for example.

The horizontal position counter 23 is reset by the horizontal synchronization signal H from the synchronization separation circuit 21, and counts the clock pulses from the clock pulse generation circuit 17. This horizontal position counter 2
The count information of 3 is also added to the address circuit 24. Further, this address circuit 24 includes:
The previous vertical synchronization signal is also input. This address circuit 24 can generate address data regarding the horizontal and vertical directions of the image obtained by the currently input composite video signal.

As described above, the buffer memory 15 stores the contents of a teletext packet when it arrives. The data stored in this buffer memory 15 is processed by a microcomputer.

Central processing unit (hereinafter referred to as CPU) 30
decodes the data contents of the buffer memory 15. For example, what is the data format?
What the program is like.

For example, a case will be explained in which it is desired to display a weather forecast as a teletext broadcast. If it is desired to display the weather forecast, a command signal for processing the weather forecast data can be input by operating the keyboard 40. The weather forecast program is specified by the program code shown in FIG. For example, the program code
Assuming that the data of Pc1 is sending a weather forecast, this program code Pc1 is processed by the CPU 30. As a result, if the data of this program code Pc1 matches the data designated from the keyboard 40, it is determined that the data in the buffer memory 15 is data for a weather forecast. A command signal for reproducing the weather forecast specified from the keyboard 35 is stored in a random access memory 32 (hereinafter referred to as RAM).

The weather forecast pattern data read from the buffer memory 15 is finally stored in the pattern memory 33 as character data and symbol data. The color data is stored in color memory 34.

The data read from the buffer memory 15 is itself stored in the pattern memory 33 as character data or storage data, but if the transmission method is a code transmission method, the data read from the buffer memory 15 is decoded and read. Predetermined character data, that is, characters, symbols, and graphic data may be read out from the only memory (hereinafter referred to as ROM) and stored in the pattern memory 33 or the like. Therefore, furthermore,
A character ROM 39 is prepared.

Based on the data derived from the buffer memory 15 as described above, the pattern memory 33 stores characters,
Symbol and graphic data are stored, but since a teletext packet in a vertical period is extracted only once, sufficient data for character display cannot be obtained. Therefore, each time there is a vertical synchronization period and each time a desired program is detected, the data is sequentially stored in the pattern memory 33.

When data is stored in the pattern memory 33 and color memory 34, the address at which the data is stored may be determined by inputting, for example, address designation data that determines the storage address together with the data.

When data stored in the pattern memory 33 and color memory 34 is read out and displayed, the data in the pattern memory 33 is sent to the pattern decoder 35, and the data in the color memory 34 is sent to the color decoder 36 to be converted to DC. is converted to
The output interface 37 synthesizes the signals. Then, it is combined with the composite video signal in a combining circuit 38. The timing of reading data from the pattern memory 33 and color memory 34 is determined by a command signal from the CPU 30. The CPU 30 is a constant address circuit 24
The address data (corresponding to the current screen beam irradiation position) input from the screen is being deciphered. When this address data matches the desired display designation data set in the RAM 32, read signals corresponding to these address data are applied to the pattern memory 33 and color memory 34. The display specification data is included in the program read and stored in the RAM 32, and this display specification data can be changed,
The display system can be set in various ways depending on the program switching.

This invention is particularly effective in preventing missing characters when a group of data is used repeatedly. That is, in the broadcasting system, a teletext packet of the code transmission system is superimposed on a preset horizontal period of a plurality of vertical synchronization signal periods. A group of data is formed by the arrival of these vertical synchronization signals multiple times, and if this is the first cycle (page), the same result will occur even if the next second cycle (page) is processed. A collection of content data can be formed. In the case of such broadcasts, good data processing (data deciphering) was performed during the first cycle of processing, but some data may be missing during the second cycle of processing. There is. Therefore, in the present invention, when the data stored in the pattern memory 33 and color memory 34 is to be used repeatedly, a check function is activated when reading the data.
Therefore, when leading the data to the display section via the pattern decoder 35 and color data 36, the data is transferred from the pattern memory 33 and color memory 34 to the check circuit 4.
1 to determine whether the data is reliable. For example, as shown in FIG. 3, when the data indicates hiragana, each word is checked by the check circuit 41 to see if it is normal.

On the other hand, the auxiliary pattern memory and auxiliary color memory 42 store data indicating the above-mentioned hiragana. The auxiliary pattern memory and auxiliary color memory 42 hold data before the page control packet is received and the screen is erased.
Now, the hiragana data in the pattern memory 33 and color memory 34 is data 4 shown in FIG.
Part of 4? If some parts are missing, like
This is detected by the check circuit 41. Then, a portion 46 (FIG. 3b) corresponding to the missing portion is read out from the data 45 in the auxiliary pattern memory and auxiliary color memory 42, and is treated as regular data. Next, when a page control packet is received, the auxiliary pattern memory and auxiliary color memory 42 are used as work memories, and the pattern memory 33 and color memory 34 retain the data as they were before the page was switched. The check circuit 41 then checks the contents of the auxiliary pattern memory and auxiliary color memory 42. Here, if there is ambiguous data, the contents of the pattern memory 33 and color memory 34 are used as before. As a result, according to the device of the present invention, if a character is missing on the screen, it can be compensated for, and an unsightly screen such as blurred colors can be prevented.

Furthermore, in the present invention, the teletext packet itself may be stored in the packet storage section 48. That is, when a certain program is received, the display data is obtained by receiving multiple teletext packets,
Data is accumulated in the pattern memory 33 and color memory 34, and when it becomes possible to display (one page ends)
will be displayed. Furthermore, in a teletext packet, the same content as one page is sent repeatedly. Therefore, if the teletext packet of the previous page is stored in the packet storage unit 48, even if some of the current data is illegible, the previous teletext packet can be read out and used. . This makes it possible to further stabilize information processing.

As described above, the present invention provides a teletext broadcasting receiving apparatus that can compensate for blanks on the playback screen when a dropout of transmission data occurs by inserting information from the previous cycle into the dropout portion. can.

[Brief explanation of the drawing]

1A to 1D are explanatory diagrams showing the format of television signals in teletext broadcasting, FIG. 2 is an explanatory diagram showing the configuration of an embodiment of the present invention, and FIGS. FIG. 3 is an explanatory diagram schematically showing an example of data to be handled. 13...Waveform shaping circuit, 14...Sampling circuit, 15...Buffer memory, 30...CPU,
31...ROM, 32...RAM, 33...Pattern memory, 34...Color memory, 35...Picture decoder, 36...Color decoder, 41...Check circuit, 42...Auxiliary pattern memory and auxiliary color memory , 48...Packet storage section.

Claims (1)

[Claims] 1. A group of data constituting at least one screen is superimposed on a preset horizontal period of a plurality of vertical synchronization periods in one cycle, and the group of data is repeated in the first and second cycles. In a teletext broadcasting receiving device that receives a teletext broadcasting signal of a code transmission method transmitted by a teletext broadcasting system, a first teletext broadcasting device that stores data for the first and second cycles of the display data of the teletext broadcasting signal, respectively. , a second memory section, the data of the first cycle is held in the first memory section, and when the data of the second cycle is read from the second memory section and introduced into the display section. . A teletext broadcasting receiving apparatus, characterized in that when the data read out from the second memory section is erroneous, the data corresponding to the erroneous data from the first memory section is read out and used.