JPH0683437B2 - Teletext receiver - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a teletext receiving apparatus that is transmitted by being superimposed on a television signal.

2. Description of the Related Art A character signal is sent together with a program number and a page number, and these numbers are stored in a large capacity memory together with program data (code signal).

Problems to be Solved by the Invention Although most of the signals sent to the large-capacity memory can be stored, if the program number and page number are recorded together with the program content, if they are stored consecutively ， It is difficult to find the beginning of the program. On the other hand, if the address is switched in program units or page units in order to eliminate this drawback, a gap is created in the memory, and the utilization efficiency decreases. The present invention eliminates the above-mentioned conventional drawbacks, and provides an apparatus capable of easily finding the beginning of a program or page without lowering the utilization efficiency of a large capacity memory.

Means for Solving Problems The present invention is provided with an auxiliary memory for storing only a program number and a page number, and simultaneously storing a leading program in which data (code signal) of contents of the page is stored. Is.

According to the present invention, by pressing the index button, the program and page numbers stored in the auxiliary memory can be displayed on the CRT, and as a result, the designated program and page can be read out somewhere. The data for one screen can be written in the display memory and displayed on the CRT in a short time.

Embodiment FIG. 1 shows an embodiment of the present invention, which is a part of a coded teletext receiver. In the figure, 1 is an index memory that functions as an auxiliary memory, 2 is a large-capacity memory, 3 is a buffer memory (work RAM for data processing), 4 is a display memory,
Reference numeral 5 is a ROM for kanji and graphics, 6 is a buffer memory for one line, 7 is an error correction circuit, 8 is a code signal received, and the contents to be displayed and information regarding the handling of program data (program number, page) No., audio signal, video signal, compressed or not, color signal, flushing, etc.) and sends data to the write / read (R / W) control circuit 9, Is a write / read control circuit, 10
Is an address generation circuit, and 11 is a key input circuit.

The operation when there is no key input will be described. As we all know,
In teletext, it is possible to superimpose and send the text signal during multiple horizontal scanning periods (H) during the vertical blanking period, but first of all, it is received from the lowest numbered H (tentatively 10H and 273H). And The line buffer 6 stores 272 bits of data after the Fleming code, and the error correction circuit 7 performs error correction. 190 bits (about 23.8 bytes) of the corrected data are judged by the judging circuit 8 and written to the index memory 1 and the large capacity memory 2 in order from the packet at the beginning of the program. In this case, as the information interrupted in synchronization with the program content on the main screen, the program number and the code (corresponding to the bit) indicating the interrupt signal are written in the index memory 1, but the program content is not written in the main memory 8. .

Assuming that the first received program is “04” page of “120” program, BCD (4bit) 5 digits and main memory address 20 digits total 40
Bits are written to the index memory 1, but 48 bits, that is, 6 bytes are written including other information. If the index memory 1 is composed of 64 Kbits × 8, about 11,000 pages of memory can be stored (65536 ÷ 6≈10922). If the data per page (voice in pattern and color) is 1.0 Kbytes on average, the main memory 2 can store about 1000 pages. Index memory 1
Since it is possible to store program numbers and pages that are not stored in the main memory 2, the remaining 8 bits of the 48 bits are used to determine whether H (4 bits) in which the signal is superposed or not. (1 bit), whether it is stored in the main memory 2 (1 bit), or the like may be stored. The programs are stored in sequence below.

It is expected that about 50 to 100 programs will be sent per 1H due to the waiting time, so if it is used up to 8H in the 10th to 21H, (50 × 8) to (100 × 8) or 400 to 800 About the program is sent.

The current main memory of a personal computer is a large one, which is 1 MB, but it is expected that the capacity will increase in the future.
Since the cost of memory is reduced, 5-10
Think of M bytes.

Therefore, 80 programs are sent for 1H on average and 5 programs are sent for 1 program on average.
If 8H is used as a page, 80 × 5 × 8 = 3200 pages, and all programs can be memorized with 3.2 MB. The maximum number of characters per screen is 480 characters x 16 = 960 bytes, which is much smaller in reality. When there is a lot of color and sound information, there should be few letters.

It is possible to store all the programs sent as described above (however, the above 80 programs are sent repeatedly in one cycle in about 5 to 15 minutes).

Next, reading from the main memory 2 will be described. If you operate the key input unit 11 and specify the m page of n programs, first R /
The W control circuit 9 drives the address generator 10 to send the address to the index memory 1 to sequentially change the address and find the address x of the n program m page. This address data is input to the address generating circuit 10, the address is sent from the address generating circuit 10 to the main memory 2, and the stored contents are read. Since data of the same length as the total number of packets on this page can also be read, the address generation circuit 10 changes the address according to this content. Data of n pages m pages of k programs from the main memory 1 is transferred to the buffer memory 3, the contents of the buffer memory 3 are changed and the contents are read, the code data is converted into pattern data by the Kanji graphic generation ROM 5, and the video RAM 4 Write to Y memory of. When the data read out from the buffer memory 3 is a color code, the address generation circuit 10 discriminates it and writes it in each color code memory (corresponding to bit) of R, G, B of the video RAM 4. In the figure, each R, G, B memory is the same as the brightness memory on the assumption that each dot is colored.
× 256 ≈ 52.2K bits. Considering the flushing and cone seal for each dot, the capacity of the video RAM 4 becomes even larger. Since the buffer memory 3 has a capacity of 64 Kbytes, almost one program can be stored.

Next, when the program input is instructed from the key input unit 11, the code signal read from the index memory 1 is converted into a character pattern by the Kanji / graphic ROM 5 and written in the video RAM 4. Since the video RAM 4 is read in synchronism with the vertical and horizontal scanning of the CRT display, the program number and the page number are successively displayed on the CRT. The format of the program table is the address generation circuit 10
Then, it is determined by what write address is given to the video RAM.

Next, a case where only the first line (of each page) of each program is read from the main memory 2 will be described. When the "heading" key is entered from the key input unit 11, only the first line (of each page) of each program in the main memory 2 is read out. This is because the contents of the main memory 2 are transferred to the buffer memory 3, the address generating circuit 10 discriminates the code data of the first row, the address is sent to the video RAM 4, and the code data is read from the buffer memory 3.
Convert to pattern signal with Kanji / graphic ROM5 and write to video RAM4. When the read address of the video RAM4 is changed in units of fields, the characters displayed on the CRT scroll vertically. That is, all program numbers can be displayed by vertical scrolling.

With the configuration as described above, the contents of the large capacity memory 2 and the program number can be easily known by the program number and page number dedicated memory 1.

Effects of the Invention According to the present invention, the following effects can be obtained.

(1) Code signals of programs (or pages) of different lengths can be stored in the large capacity memory without any space.

(2) The code signal of a desired program can be quickly read from the large capacity memory.

(3) A program number table can be easily created.

(4) The first line of each program can be sequentially displayed.

[Brief description of drawings]

FIG. 1 is a block diagram of a teletext receiver according to an embodiment of the present invention. 1 ... Index memory, 2 ... main memory, 3 ... buffer memory, 4 ... video RAM, 5 ... ROM, 6 ... line buffer memory, 7 ... error correction circuit, 8 ... determine code signal Circuit, 9 ... write / read control circuit, 10 ... address generation circuit.

Claims (1)

[Claims] 1. A video RAM for converting a received teletext signal into an image signal, and a work RAM for data processing,
An interrupt mode in which an auxiliary memory for storing at least a program number and a page in the teletext signal and a large-capacity memory for storing a large number of teletext screen signals are provided, and which is interrupted in synchronization with the program content of the main screen. When receiving a program transmitted by, the large-capacity memory is not stored, but the identification number indicating the interrupt mode is stored in the auxiliary memory together with the program number and page number. Upon reception, a teletext screen signal is stored in the large-capacity memory, and address information indicating where in the large-capacity memory the received program content is stored is stored in the auxiliary memory together with the program number and page number. Also, it has a function of displaying the program numbers and the identification numbers stored in the auxiliary memory as a list on the TV screen. When reading out the screen, the teletext receiving device is characterized in that the signal of the screen is read from the large capacity memory according to the address information and displayed.