JPS63995B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a television teletext receiving apparatus, and more particularly to a television teletext receiving apparatus for displaying a vertically scrolling transmission mode program.

According to the report of the Radio Technology Council in March 1982, television teletext broadcasting is carried out using the method described below.

The teletext screen is divided into small sections (color blocks) based on the page (full display section) in the case of full-page fixed display. The number of color blocks constituting the entire display section is 527, which is a combination of 31 horizontal blocks x 17 vertical rows. The number of pixels that make up a color block is 8 dots horizontally x 12 dots vertically, and the entire display area is
It consists of 248 dots x 204 vertical dots, a total of 50,592 dots. The horizontal rows of pixels are called pattern lines, and the entire display section consists of 204 pattern lines.

All digital data signals (text signals) for text broadcasting, such as dot information and control signals obtained by scanning text and graphic patterns in the horizontal direction and dividing the image into 248 dots per pattern line, are sent to the TV in units of data packets. 10th H (273rd H for even fields) to 21st H (284th H for even fields) of scanning line numbers during the vertical blanking period of the video signal
Data packets are time-divisionally superimposed on any two scanning lines between them. Data packets include page control packets (PCP) that transmit control signals related to the entire page such as program number and page number, and color code packets (CCP) that transmit color signals that specify coloring, blinking, concealment, etc. for each color block. ), a block data packet (PDP) that transmits binary digital data obtained by horizontally scanning characters and graphic patterns (one pattern line mentioned above is included in one PDP packet), and a signal for horizontal scrolling. There are six types: horizontal scroll data packet (HDP), program index packet (PIP) that transmits the program number of the teletext program being transmitted, and dummy packet (DMP) that is transmitted when broadcast data packets cannot be transmitted in the superimposed section. .
A data packet consists of a header section followed by an information data section, and the header section contains a synchronization clock/data section.
Run-in signal (CR), framing code signal (FC) for frame synchronization, and service identification/interrupt signal (SI/IN) that indicates the type of broadcast service.
and a data identification signal (DI) indicating the type of data packet, and the information data section is composed of pattern data and a control signal. The bet part consists of 48 bits, the information data part consists of 248 bits, and the entire data packet consists of 296 bits.

FIG. 1 is a schematic block diagram showing a conventional television teletext receiving apparatus. In the configuration, the parts that make up an ordinary television receiver include a tuner 2 to which an antenna 1 is connected, which is connected to a cathode ray tube 13 via an intermediate frequency amplification circuit 3, a video amplification circuit 16, and an output interface circuit 12. configured. In the character signal receiving section, an intermediate frequency amplification circuit 3 is connected to a buffer memory 5 via a sampling circuit 4.
are connected to a buffer memory 5, a central processing unit (CPU) 6 such as a microprocessor, a pattern memory 7, a color memory 8, and a program selection device 10.
The ROM 14 and RAM 15 are connected to each other through a bus line 9, the pattern memory 7 and color memory 8 are connected to a read control circuit 11, and the pattern memory 7 and color memory 8 are connected to an output interface circuit 12. be done.

In operation, a television signal received by the antenna 11 and superimposed with a character signal is channel-selected by the tuner 2 and converted into a video intermediate frequency, and further amplified and detected by the video intermediate frequency amplification circuit 3 to become a video signal. converted. When receiving normal television broadcasting, this video signal is amplified by a video amplification circuit 16 and driven to a cathode ray tube 13 via an output interface circuit 12. On the other hand, in the case of receiving a teletext broadcast, the character signal superimposed on the video signal is separated from the video signal by the sampling circuit 4, and this character signal is temporarily stored in the buffer memory 5. Since the bit rate of the transmitted character signal is much faster than the data processing speed of the CPU 6, the buffer memory 5 temporarily stores one packet of character signals, and then transfers the character signal to the CPU 6 until the next character signal arrives. is used for reading as necessary. Among the stored character signals, the signal of the teletext program selected by the program selection device 10 is sent to the buffer memory 5 by the CPU 6.
Character pattern data is transferred to pattern memory 7 and color data is transferred to color memory 8 via bus line 9 and stored therein. The procedure for CPU 6 to process character signals is stored in ROM 14, and RAM 15
is used for temporary data storage and storage during processing. When one page of data is stored in the pattern memory 7 and color memory 8,
A read control circuit 11 sequentially reads out the stored data, and a character screen is displayed on a cathode ray tube 13 via an output interface circuit 12.

By the way, as a transmission mode for teletext broadcasting, there is a vertical scroll transmission mode in which the character screen sequentially moves from the bottom to the top on the cathode ray tube. In the vertical scroll transmission mode, scrolling is performed in the vertical direction (in the vertical direction of the cathode ray tube) once per vertical synchronization of the television signal. In other words, the character screen is 1 vertical synchronization
Move line by line from bottom to top.

FIG. 2 is an explanatory diagram showing the relationship between the character screen of a cathode ray tube and the number of lines. In the vertical scroll sending mode, a total of 12 lines from line 0 to line 11 are fixedly displayed as page headers. Scrolling is then performed on the remaining lines. That is, initially, line 12 to line 20
3 is displayed on the screen, and the remaining lines 204 to 215 are not displayed on the screen as hidden parts. Then, in the next vertical synchronization, lines 0 to 11 and lines 13 to 204 are displayed on the screen. In other words, line 12 is scrolled. Furthermore, in the next vertical synchronization, lines 0 to 11 and lines 14 to 205 are displayed on the screen. In this way, in the vertical scroll transmission mode, lines 0 to 11 are fixedly displayed as page headers, such as the program name, and the text screen is scrolled in the remaining lines 12 and below.

By the way, as described above, the pattern data and color data are read out from the pattern memory and color memory, respectively, by the readout control circuit in synchronization with the horizontal synchronizing signal of the television signal. The addresses of pattern memory and color memory are divided into addresses corresponding to the vertical direction of the screen (vertical address) and addresses corresponding to the horizontal direction of the screen (horizontal address). The data stored at the address is read from the respective memory and displayed at the corresponding position on the screen. In general, a vertical address for reading data is created by counting the horizontal synchronizing signal of the television signal, and a clock generator that is separately provided is clocked in synchronization with the horizontal synchronizing signal of the television signal. By counting, a horizontal address for reading data is created. As mentioned above, the color blocks are vertical.
Since 12 lines are included in one block, the read address of the color memory must be the same for the 12 vertical lines (that is, during the 12 counts of the horizontal synchronizing signal). That is, generally, the vertical address of the color memory can be obtained by dividing the frequency of the horizontal synchronizing signal by 1/12 and counting it.

However, in the vertical scroll sending mode, the lines are sequentially scrolled as described above, so the frequency division ratio must be changed in accordance with the scrolling. For example, in the case of 1-line scrolling, the division ratio for the color block portion including the scrolled line is 1/11 and for the other 1/12, and in the case of 2-line scrolling, the division ratio for the color block portion including the scrolled line is 1/11. The division ratio of is 1/10 and the others are 1/10.
Must be 12. In vertical scroll sending mode, simply dividing the frequency by 1/12 will not work.
Pattern data and color data no longer match, causing color shift on the screen.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a television teletext multiplexing receiving apparatus that does not cause color shift on the screen even in vertical scroll transmission mode.

To summarize, the present invention generates a vertical address of a pattern memory by counting horizontal synchronization signals of a television signal, adds the vertical address of the pattern memory to an address input of a read-only memory, and adds the vertical address of the pattern memory to the address input of a read-only memory. By storing the vertical address of the color memory corresponding to the vertical address of the pattern memory added to its address input, it creates the vertical address of the color memory as its output, and uses the pattern when reading program data in the vertical scroll transmission mode. This eliminates mismatch between data and color data.

The above objects and other objects and effects of the present invention will become more apparent from the following detailed description with reference to the drawings.

FIG. 3 is a schematic diagram showing a device for creating a pattern memory vertical address and a color memory vertical address for reading data of a vertical scroll transmission mode program, among the readout control circuits used in carrying out the present invention.

In the structure, the output side 23 of the vertical counter 21, which is provided with an input terminal 25 for the horizontal synchronizing signal H of the television signal, an input terminal 26 for the vertical synchronizing signal V, and a preset terminal 27, receives the vertical address P of the pattern memory. At the same time as outputting address 1/
It is connected to the address input side of the 1/12 ROM 22, and the output side 24 of the address 1/12 ROM 22 outputs the color memory vertical address C.

FIG. 4 is a block diagram showing further details of the vertical counter 21 and its preset terminal 27 shown in FIG.

In the structure, the vertical counter 21 is provided with an input terminal 25 for the horizontal synchronizing signal H and an input terminal 26 for the vertical synchronizing signal V, as described above, and its output side 23 outputs the vertical address P of the pattern memory. . The preset terminal 27 in FIG. 3 is composed of a preset data terminal 34 and a load terminal 39 for loading preset data.
The output side of the changeover switch 31 provided with a CPU terminal 37 and an initial value K terminal 38 is connected to the preset data terminal 34. The input side of the decoder 32 is connected to the output side of the vertical counter 21, and one output side 36 of the decoder 32 is connected to the changeover switch 3.
The other output side 35 of the decoder 32 is connected to the input side of the OR gate 33, and the output side of the OR gate 33 is connected to the load terminal 39.
connected to.

In operation, the vertical counter 21 receives the horizontal synchronizing signal H as a clock pulse at the terminal 25, counts it, and outputs a pattern memory vertical address P. On the other hand, the decoder 32 receives and decodes the pattern memory vertical address P, and outputs a pulse to the output terminal 35 at count 11. is terminal 3
The preset data given through 4 is loaded. The preset data is output from the changeover switch 31, but the changeover switch 31 is normally
It is connected to the CPU terminal 37 side A. and
Initially, preset data of 0 is given from the CPU terminal. This preset data is given from the CPU, but is held in a latch (not shown). Even if preset data of 0 is loaded, the count number does not substantially change, so it continues to count 12, 13, etc. At count 203, the vertical synchronizing signal V is received at the terminal 26, and the vertical counter 21 is reset to zero. Then, counting is performed again by the clock of the horizontal synchronizing signal H, and at count 11, the preset terminal data is loaded again. After being reset once by the vertical synchronizing signal V, preset data of 1 is given from the CPU. (From then on, the preset data will increase by 1 each time it is reset, and will go from 215 to 0 again.)
Return to ) In this way, when counting the next 12, preset data 1 is loaded, so the count jumps from 11 to 13. Then, counting continues, and at count 204, the vertical synchronizing signal V
A reset is performed.

From then on, the count is performed in the same way as above, 1 to 11, 14 to 205, then 1 to 11, 15 to 206, and so on.
~11, after counting from 24 to 215, the second
As is clear from the diagram, 1-11, 25-
215, must be counted as 12. This is because, as mentioned above, it is necessary to scroll cyclically between lines 12 and 215. This operation will be explained below.

When the count reaches 215, the decoder 32 outputs terminal 3.
6, the selector switch 31 is controlled thereby and the switch is temporarily connected to the initial value K terminal 38 side B. The initial value K is preset to 12, and the vertical counter 21 is given 12 preset data. Further, the output pulse of the terminal 36 is applied to the load terminal 39 via the OR gate 33, and 12 preset data are loaded into the next count value. The count value of the vertical counter 21 is predetermined to cycle from 0 to 215, so the count value after 215 is 0, and 12
is loaded, so the next count value will be 12. In this way, 215 is followed by a count of 12. Then, it is reset by the vertical synchronizing signal V, and thereafter counting from 0 to 11, 26 to 215, 12, and 13 is performed. As described above, the vertical address P for reading the pattern memory for the vertical scroll transmission mode program is created.

Now, returning to Figure 3, address 1/12ROM
The stored data for address No. 22 (which becomes the color memory vertical address) is predetermined as follows. That is, addresses 0 to 11 → data 0, addresses 12 to 23 → data 1, addresses 24 to 25 → data 2, ..., addresses 192 to 203 → data 16, address
204-215 → data 17.

Then, the pattern memory vertical address P created as described above is given to the address input of the address 1/12 ROM 22, and the stored data is read out to the output side 24 and output as the color memory vertical address C. Ru.

For example, the pattern memory vertical address P is...11,
12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22,
When changing to 23, 24, etc., address 1/
12The color memory vertical address C read from the ROM22 is...0, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 2, and so on.
11, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22,
In the case of 23, 24...0, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 2,...and further...11, 14, 15, 16, 17, 18, 19, 20, 21, 22,
In the case of 23, 24,…0, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 2,...and...11,
In the case of 15, 16, 17, 18, 19, 20, 21, 22, 23, 24,...0, 1, 1, 1, 1, 1, 1, 1,
1, 1, 2,... As is clear from this, as the line is scrolled line by line, the frequency division ratio of the read address of the color data of the color block including the scrolled line is automatically changed.

Using the pattern memory vertical address P and color memory vertical address C created in this way, and further using the horizontal address created by the method using the general clock generator described above, the apparatus shown in FIG. By configuring the readout control circuit, programs in the vertical scroll transmission mode can be displayed without color shift.

As described above, according to the present invention, it is possible to obtain a television teletext multiplexing receiving apparatus that can display programs in vertical scroll transmission mode on the screen without color shift.

[Brief explanation of the drawing]

FIG. 1 is a schematic block diagram showing a television teletext receiving apparatus, FIG. 2 is an explanatory diagram showing the relationship between a character screen and pattern lines, and FIG. FIG. 4 is a schematic diagram showing an apparatus for generating pattern memory vertical addresses and color memory vertical addresses for reading data of a scroll output mode program; FIG. 4 shows further details of the vertical counter shown in FIG. 3 and its preset terminal; It is a block diagram. In the figure, 1 is an antenna, 2 is a tuner, 3
is an intermediate frequency amplification circuit, 4 is a character signal sampling circuit,
5 is a buffer memory, 6 is a central processing unit, 7 is a pattern memory, 8 is a color memory, 9 is a bus line, 10 is a teletext program selection device, 11 is a readout control circuit, 12 is an output interface circuit, 1
3 is a cathode ray tube, 14 is a ROM, 15 is a RAM,
16 is a video amplification circuit, 21 is a vertical counter, 2
2 is an address 1/12 ROM, 31 is a changeover switch, and 32 is a decoder.

Claims (1)

[Scope of Claims] 1. A device that receives character signals for television text multiplex broadcasting, which are transmitted superimposed on the vertical blanking period of a television video signal, and displays a character screen on a display such as a cathode ray tube. The television video signal includes a horizontal synchronization signal and a vertical synchronization signal, and the television teletext broadcasting includes at least a program in a vertical scroll transmission mode in which the character screen sequentially moves from bottom to top on the display. The character signal includes at least pattern data for transmitting character and graphic data and color data for transmitting data for coloring the character screen, and a pattern memory for storing the received pattern data; , a color memory for storing the received color data, and a color memory for displaying the character screen on the display,
means for reading out the pattern data and the color data stored in the pattern memory and the color memory, respectively, in synchronization with the horizontal synchronization signal; means for generating a pattern memory vertical address for reading out the pattern data of the vertically scrolling transmission mode program in response to a synchronization signal; means for creating a color memory vertical address for reading color data. 2. The means for creating the color memory vertical address includes adding the pattern memory vertical address to an address input of a memory in which the color memory vertical address is stored as data in advance, and adding the pattern memory vertical address to the color memory vertical address corresponding to the input pattern memory vertical address. The television teletext multiplex broadcasting receiving apparatus according to claim 1, which is means for reading a vertical address.