JPH04354284A - Receiver for teletext broadcasting - Google Patents

Abstract

PURPOSE:To watch a desired program without requiring waiting time by separating and extracting a text signal from a receiving signal by a text signal separation circuit and storing the extracted character signal in a non-volatile magnetooptical disk. CONSTITUTION:An antenna 1 is connected to a channel selection/demodulation circuit 2 and serves to demodulae the video signal of a selected channel. A synchronizing separation circuit 3 separates a horizontal synchronizing signal from a video signal and generates a reference clock for waveform equalization and text signal separation. On the other hand, a waveform equalization circuit 4 forms the waveform of the video signal while referring to the reference clock and outputs it to a text signal separation circuit 5. The text signal separation circuit 5 separates the text signal according to the reference clock and stores it in a buffer area 6-1 provided within a magnetooptical disk 6. The magnetooptical disk 6 is provided with the buffer rear 6-1 and a storage area 6-2. Thus, much television teletext broadcasting can be stored over a long period of time.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a TV receiver for teletext broadcasting which receives and displays signals broadcast in teletext multiplex format.

0002

2. Description of the Related Art Teletext broadcasting is a still image information broadcast centered on text information that is transmitted superimposed on the radio waves of general television programs, making use of the time gaps in television broadcast radio waves. Such teletext broadcasting began in 1985, and currently there are six broadcasting stations in the Kanto region alone, broadcasting about 400 programs, and the number of users is gradually increasing. Transmission and reception methods for such teletext broadcasts are described in the Teletext Technology Handbook (edited by the Broadcasting Technology Development Council, published by Kenrokukan) and the Official Gazette No. 126 (Ministry of Posts and Telecommunications Ordinance No. 77) dated October 15, 1985. This is explained in detail in ``Standard System for Transmission Regarding Television Teletext Broadcasting''.Here, matters necessary for explanation of the later embodiments will be mainly explained.

FIG. 4 is a diagram illustrating a method of superimposing teletext onto a television image signal. Here, 14H to 16H within the vertical synchronization period (vertical blanking period) of 1 second of television broadcasting, that is, 525 horizontal scanning periods.
, 21H, 277H to 279H, and 284H are used to transmit the character signal. Therefore, TV
1 field of screen (262.5 horizontal synchronization period = 1/60
(seconds), information for four horizontal scanning periods can be transmitted. Here, the teletext signal is a code signal composed of a digital signal, and can transmit 296 bits of information in one horizontal scanning period.

FIG. 6 is a diagram for explaining the content of information transmitted during one horizontal synchronization period.
1 and the framing code 602 are composed of 16 bits and 8 bits, respectively, and are used for data synchronization. Prefix 603 (14 bits), data block 6
04 (176 bits) and the check code 605 (82 bits) is called a data packet, and the check code 605 is used for error correction of 8 bits or less in the data packet. Prefix 602 14
The first 8 bits are called a service identification part. FIG. 5 is a diagram showing the types of service identification, and teletext is broadcast using transmission modes 1 to 4.

[0005] The data block contains teletext data used on the receiving side, and the receiving side creates text program data by concatenating multiple 176-bit (=22 byte) data blocks. There is.

FIG. 8 is a diagram illustrating the structure of text program data.

The beginning of the program data is 22 bytes of program management data, which includes a magazine number for identifying a program group and a program number for identifying a program, which are used to identify the program. In addition, this program management data includes a program content change flag that indicates whether the program content has been updated.This flag is reversed when the program content has been updated, so this flag indicates whether the number content has been changed. It is possible to determine whether The program data consists of the above-mentioned program management data and data of each page, and the data of each page is composed of a header and several data units. The header of each of these pages includes a magazine number and program number for identifying the program, as well as a page number for identifying the page.

[0008] When a teletext program is transmitted, the program is identified by the horizontal scanning period used for transmission, the transmission mode in that horizontal scanning period, the magazine number, and the program number.

FIG. 9 is a diagram for explaining the identification of such a program.As is clear from this diagram, a teletext program is divided into one horizontal scanning period, one transmission mode, and one magazine. number, and is recognized and transmitted by a certain program number. Currently, broadcast stations are broadcasting from several dozen to 10
Approximately 0 programs are sent out in parallel.

FIG. 10 is a diagram for explaining the distribution when a teletext program transmitted in one horizontal scanning period consists of a plurality of programs.

[0011] Here, n programs are sequentially sent out from the first page. In general, the number of pages that make up a teletext program differs for each program, so for example, if program 1 ends on the kth page, program 1 will be transmitted from the first page again in the next episode. That will happen. Furthermore, since the amount of data for one page also differs for each program or page, in current teletext broadcasting, one page of one program is transmitted approximately every 20 to 30 seconds. The number and amount of data on each page are adjusted.

[0012] As mentioned above, there are currently six broadcast stations in the Kanto region that broadcast text multiplex programs. The amount of data sent varies greatly. For example, in a station that has many market programs such as news and stock market information, the program content is updated frequently.
The amount of data sent per day is extremely large. for example,
For example, TV Tokyo's Nikkei Telepress has about 25 programs whose content is updated frequently, so the content is updated about 40 times a day. Assuming that each program has an average of 20 pages and each page has an average amount of data of 1 Kbyte, this means that about 20 Mbytes of data is being sent out per day.

[0013] Various kinds of receiving apparatuses for receiving teletext as described above are currently on sale as color television receivers incorporating a teletext adapter and a receiving circuit.

[0014] However, in teletext broadcasting, the data of the desired program is sent at a rate of one page every 20 to 30 seconds as described above, so it is also sent at a rate of one page every 20 to 30 seconds. Only the programs that have been received can be played back and watched.

[0015] As described above, it takes a long time to receive and watch one program, so at present, a memory is provided in the receiving device, and in this memory, programs to be viewed are reserved and stored in advance. Devices have also been developed that allow users to watch reserved programs without having to waste time. Such television equipment is
It has a memory capacity of tens to thousands of pages.
When the content of a reserved program is updated, only the latest content is stored.

[0016]

However, with a color television equipped with a conventional teletext adapter or teletext receiving circuit, it takes too much time to watch a program for the reasons mentioned above. Furthermore, even in television receivers that have a built-in memory that can reserve and store the programs you want to watch, the capacity of the reservation memory is insufficient, and since such memory is generally composed of semiconductor memory, the device When the power is turned off, the contents are erased, so there is a problem that long-term storage of data is not possible. Furthermore, the program reservation memory described above can only display the stored program data on the television monitor of the device, and the methods of using the data are limited.

The present invention has been made in view of the above-mentioned conventional example, and stores many TV teletext programs for a long period of time.
To provide a television receiver for teletext multiplex broadcasting with which a desired program can be viewed at a desired time with almost no waiting time.

[0018]

[Means for Solving the Problems] In order to achieve the above object, the teletext broadcasting receiving apparatus of the present invention has the following configuration. That is, it is a television receiver for teletext broadcasting that can separate and display a character signal from a signal transmitted as a character multiplex, and includes an extracting means for separating and extracting a character signal from a received signal, and an extraction means for separating and extracting a character signal from a received signal; and nonvolatile storage means for storing character signals.

[0019]

[Operation] The above structure operates to separate and extract the character signal from the received signal and to store the extracted character signal in the nonvolatile storage means.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram showing a schematic configuration of a receiving apparatus for teletext broadcasting according to a first embodiment of the present invention.

Reference numeral 1 denotes an antenna, which receives a television broadcast signal and outputs it to the channel selection/demodulation circuit 2, which selects the channel selected by the interface section 16.
Demodulates to TV image signal. The synchronization separation circuit 3 separates horizontal and vertical synchronization signals from the demodulated television image signal,
Generates a reference clock for waveform equalization and character signal separation. In response to this, the waveform equalization circuit 4 shapes the waveform of the video signal and outputs it to the character signal separation circuit 5. Character signal separation circuit 5 separates character signals and sends them to buffer memory 17 while referring to the reference clock. Among the data in the buffer memory 17, the CPU 7 selects the data of the program specified by the user through the interface section 16. This selected data is stored in the program ROM
According to the decoding program on 18, it is converted into a dot pattern using the character generator 9, and written into the color memory/pattern memory 11 together with color attribute data. The data in this memory 11 is stored in the display control unit 1
After being output to the color matrix 12 according to an output command from 0, the signal is converted into an RGB signal and output as a video signal.

On the other hand, the CPU 7 similarly converts the additional sound data added to the video signal into an audio signal using the electronic sound generator 13 according to the decoding program on the program ROM 18 and outputs it.

The antenna 1 is connected to a channel selection/demodulation circuit 2, and the video signal of the selected channel is demodulated. The synchronization separation circuit 3 separates the horizontal synchronization signal from the video signal and generates a reference clock for waveform equalization and character signal separation. On the other hand, the waveform equalization circuit 4 shapes the waveform of the video signal while referring to this reference clock and outputs it to the character signal separation circuit 5. The character signal separation circuit 5 separates character signals according to this reference clock and stores them in a buffer area 6-1 provided in the magneto-optical disk 6. This magneto-optical disk 6 has a buffer area 6-1 and a storage area 6-2. A work RAM 8 used as a work area for the CPU 7, an optical disk 6,
CPU 7, character generator 9, electronic sound generator 1
3. The color memory/pattern memory 11 and the display clock generation circuit 10 are connected by a bus line 15.

Here, the teletext signal of one channel is transmitted in four scanning sections, and each scanning section transmits an independent program group. Furthermore, program transmission for one scanning section basically has four transmission modes, and each mode transmits an independent program group.

FIG. 7 is a conceptual diagram showing the division of the buffer area 6-1 of the magneto-optical disk 6, in which an area corresponding to each transmission mode of each scanning period and an area for storing channel numbers are provided.

The storage area 6-2 also includes a program storage area for storing teletext data, the horizontal scanning period of the stored program, the sending mode, the magazine number, the channel, the program number, the stored storage date and time, and the content change flag. It has a program record table in which the following information is stored. Hereinafter, the horizontal scanning period, transmission mode, magazine number, and program number will be collectively referred to as an identification code.

[0028] When the teletext data stored in the corresponding area in the buffer area 6-1 is accumulated to the unit to be decoded, the teletext data is stored in a file to which data such as channel, storage date and time, etc. are added. The data in the buffer area 6-1 corresponding to the transferred data is erased.

At this time, the channel, identification code, and content change flag of the program stored in the buffer area 6-1 are referenced and compared with the content of the program recording table in the storage area 6-2. As a result, if the channel and identification code match, the contents of the content change flag match, and the memorized time has not elapsed beforehand (for example, 20 minutes), the buffer area 6 -1
No data is moved to the storage area 6-2.
The corresponding data in buffer area 6-1 is erased,
In cases other than the above, the teletext program data stored in the buffer area 6-1 is copied to the storage area 6-2, and the corresponding teletext program data stored in the buffer area 6-1 is deleted. When the teletext program data is transferred to the storage area 6-2 in this way, the channel of the program,
The identification code and the content change flag of the storage date and time are stored in the program recording table in the storage area 6-2. The above processing is executed under the control of the CPU 7.

The interface unit 16 allows the operator to instruct the device to play, to switch the receiving channel,
It is a part that allows inputting commands such as displaying a list of stored programs and erasing stored data, and is specifically a keypad, keyboard, remote control keypad, etc.

The list of stored programs can be obtained by referring to the contents of the program storage table in the storage area 6-2 of the magneto-optical disk 6 and outputting necessary data as a video, or by
-2, reads the beginning of each program and data file, reads the identification code, storage date and time, content change flag and channel, and outputs the video.

[0032] Reproduction of a teletext program is performed as follows. When the user inputs a program playback command from the interface section 16, the CPU 7 accesses the program data in the storage area 6-2, and uses the decoding program in the program ROM 8 to refer to the character generator 9 according to the code of the program data. to generate a dot pattern. This dot pattern is then written into the color memory/pattern memory 11 along with its color attribute data, and the data is output to the color matrix 12 in accordance with an output command from the display control circuit 10. This color matrix 12 converts this dot pattern into RGB signals and outputs them. On the other hand, the additional sound data is processed by the CPU 7.
The signal is output to the electronic sound generator 13, where it is converted into an audio signal and output.

The buffer memory 17 includes a magneto-optical disk 6
This device stores received teletext data during periods when it is temporarily unavailable, such as when the device is playing back programs or displaying a list of stored programs. Teletext programs received during this time can be stored even during operations such as . Here, a magneto-optical disk with a capacity of 300 Mbytes is used as the magneto-optical disk 6, and if the storage area 6-2 has a capacity of about 250 Mbytes, programs whose content is frequently updated (stock information, news, etc.) can be stored. Even if a user has many channels and stores all updated programs, it is possible to store teletext programs for several days.

Furthermore, since the magneto-optical disk 6 can be randomly accessed, it takes almost no time to call up a desired program during playback. Therefore, a teletext program stored on the magneto-optical disk 6 can be viewed by simply waiting for the time required to read, decode and reproduce the program from the magneto-optical disk 6.

Furthermore, since the magneto-optical disk is a replaceable storage medium, by replacing the magneto-optical disk, it is possible to store teletext programs for an even longer period, and the received and stored teletext data can also be stored for a longer period. Can be stored for a period of time.

Furthermore, by removing the magneto-optical disk on which the teletext program is stored and inserting it into another device similar to this embodiment, the stored teletext program can be played back and viewed at a different location. Data can be moved easily.

In this embodiment, the magneto-optical disk 6 is divided into a buffer area 6-1 and a storage area 6-1 of the magneto-optical disk.
-2 is physically divided, and furthermore, the buffer memory 17 is used as an auxiliary buffer area for primary storage of teletext data, and the buffer area 6-1 of the magneto-optical disk 6 is mainly used, but this is for some reason. This is so that even if reception of teletext by this device is interrupted, the teletext data up to that point can be saved.

Furthermore, the reason why the buffer area 6-1 and the storage area 6-2 of the magneto-optical disk 6 are physically separated is that data is frequently written to and erased from the buffer area 6-1. This is to prevent the possibility that if the area is not divided in this manner, a large number of file fragmentations will occur over the entire area of the magneto-optical disk 6 and the access speed of the magneto-optical disk 6 will decrease. In addition, since the buffer area 6-1 is frequently accessed, this buffer area 6-1 is placed in the center of the magneto-optical disk 6 to prevent tracking errors from occurring due to surface tilt of the magneto-optical disk 6. It is set up.

The movement of program data from the buffer area 6-1 to the storage area 6-2 on the magneto-optical disk 6 is as follows:
The transfer efficiency is improved by sequentially performing the transfer from the center to the periphery of the storage area 6-2, or vice versa.

[0040] Furthermore, when the storage area 6-2 becomes full and new program data cannot be stored, this device performs one of the following processes (a) and (b). , the user is allowed to make a selection in advance. (a) Notify the user that the storage capacity of the magneto-optical disk 6 is insufficient by an alarm or the like, and stop moving the text program data to the storage area 6-2. (a) After once clearing the contents of the program recording table in the storage area 6-2, program data is newly overwritten from the beginning of the storage area 6-2. At this time,
The program data already stored on the magneto-optical disk 6 is
Files will be deleted one by one.

Furthermore, in this embodiment, the magneto-optical disk 6 is not divided into the buffer area 6-1 and the storage area 6-2, but the channel, identification code, and
A file is added with storage date and time data, and the file is stored sequentially from the center to the edge of the magneto-optical disk 6 without determining the contents until the storage area reaches the edge of the magneto-optical disk 6. In this case, it is possible to adopt a continuous storage mode in which program data is sequentially stored while returning to the center and erasing data that has already been stored.

Furthermore, in this embodiment, the following mode can be adopted in order to further utilize the exchangeability and large storage capacity of the magneto-optical disk 6.

[0043] The teletext program data is stored in the buffer area 6-
1 to the storage area 6-2, the teletext program data and the data converted by the CPU 7 into a form that can be directly used on the computer are stored in the storage area 6-2 as separate files. Prepare. In order to provide such a mode, the magneto-optical disk 6 may be initialized in a format that can be used in a magneto-optical disk drive of a computer.

[0044] Program data for teletext broadcasts includes codes such as various control codes that have no meaning for computers, and some of the character codes themselves are different. Therefore, in a file for use on a computer, only the character code is selected from the teletext program data, and the code used on the computer, such as the ASCII code or JIS Kanji code, is stored. Give attributes to make it a text file. By doing this, the user can take out the magneto-optical disk 6 on which the teletext program is stored from the teletext receiver of this embodiment, insert it into the magneto-optical disk drive of the computer, and read it out. Character information can be immediately used as a computer text file.

[0045] If the computer has a program for converting teletext data into a character code that can be used by the computer, the initial format of the magneto-optical disk 6 may be changed so that it can be used by the computer's magneto-optical disk drive. If this device is also configured, the magneto-optical disk 6 that stores the teletext program can be installed in the magneto-optical disk drive of a computer and converted on the computer, so that it can be converted into a text file without using the above mode. can be used.

In the first embodiment, the user simply switches the receiving channel as necessary, and at a given moment only teletext data of one channel is received and stored. The second embodiment, which will be described next, improves this point.

FIGS. 2(A) and 2(B) are conceptual diagrams showing a second embodiment of the present invention, and the same numbers are given to the same members as those in the previous figures.

[0048] In this second embodiment, it is assumed that there are six channels that broadcast teletext, from the first channel (1ch) to the sixth channel (6ch).

In FIG. 2A, demodulation circuits 2-1 to 2-6 respectively correspond to channels 1 to 6, and each performs detection demodulation of the corresponding channels. Each of 3-1 to 3-6 is a synchronization separation circuit corresponding to the first channel to the sixth channel, and each of 4-1 to 4-6 is a synchronization separation circuit corresponding to the first channel to the sixth channel, respectively. It is a waveform equalization circuit, and each of 5-1 to 5-6 is a character signal separation circuit corresponding to the first channel to the sixth channel, respectively.

In this way, by providing six circuits corresponding to each channel, it is possible to simultaneously receive text broadcasts from six channels, and store text signals in the buffer memories 17-1 to 17-6 corresponding to each channel. The data is temporarily stored in the buffer area 6-1 of the magneto-optical disk 6 under the control of the CPU 7.

Buffer area 6-1 of magneto-optical disk 6
The movement of data from the storage area 6-2 to the storage area 6-2 and the erasure of data are performed in the same procedure as in the first embodiment. In this way, the teletext data from the first channel to the sixth channel can be simultaneously received and stored on the magneto-optical disk 6. This allows the user to access desired programs and obtain information as if the device were a database of text program data, without being aware of the device as a teletext receiving device.

However, in the embodiment, the demodulation circuit (2-
1 to 2-6) to character signal separation circuit (5-1 to 5-6)
The disadvantage is that it is necessary to have as many circuits as the number of channels (in this case, six). The third embodiment described below improves this drawback.

FIG. 3 is a block diagram showing the configuration of a teletext receiving apparatus according to a third embodiment of the present invention. Portions common to those described above are designated by the same numbers, and their explanations will be omitted.

The line from the antenna 1 is branched into two, one line is connected to the channel selection demodulation circuit 2 and the other line is connected to the channel selection demodulation phase measurement circuit 33. Tuning demodulation circuit 2
After passing through the waveform equalization circuit 4, the video signal demodulated by the channel selection circuit 4 extracts only the character signal by the character signal separation circuit 5, adds a code indicating which channel the program is on, and stores it in the buffer memory. 30.

On the other hand, the channel selection demodulation phase measuring circuit 33 constantly monitors the horizontal and vertical synchronization signals of the video signal of each channel while reselecting the channel at regular time intervals. 15
-2 is a bus line connecting the channel selection demodulation circuit 2, waveform equalization circuit 4, character signal separation circuit 5, CPU 231, synchronization separation circuit 32, and channel selection demodulation phase measurement circuit 33; It has a clock generation circuit, and receives a synchronization signal from the tuning demodulation phase measurement circuit 33,
The phase is constantly corrected to generate a clock that matches the synchronization signal of each channel.

[0056] The CPU 31 includes a channel selection demodulation phase measurement circuit 33.
It receives the horizontal and vertical synchronizing signals from the channel, determines which channels can be received at the same time, and outputs a channel switching command to the channel selection demodulation circuit 2 based on the determination.

FIG. 11 is a diagram for explaining the channel switching method of the channel selection demodulation circuit 2, and is a schematic diagram of vertical synchronization signals and teletext signals of channels 1 to 6.

In the figure, each of 1101 to 1112 represents a vertical synchronization signal, and each of 1121 to 1132 represents a teletext signal. As is clear from the figure, the length of one field of each channel is almost the same, but the phase of the vertical synchronization signal differs for each channel. Also, the teletext signal is input immediately after the vertical synchronization signal, and out of 262.5 scanning lines in one field,
All are included within the first 21 books. Therefore, by switching channels at appropriate timing, it is possible to extract teletext signals from multiple channels at the same time.

In the example of FIG. 11, for example, teletext signals of three channels, channel 1, channel 3, and channel 4, can be extracted simultaneously. That is, as shown as the signal selected by channel switching in FIG. 11, after receiving the teletext signal 1121 on channel 1, switching to channel 4 and taking out the teletext signal 1127, and then switching to channel 3 after receiving channel 4. The switching hand teletext signal 1125 is extracted. In this way, after receiving channel 3, it returns to channel 1 again and repeats the same switching process. In this way, in this example it is possible to receive teletext on three channels at the same time.

One field consists of 262.5 horizontal scanning periods, of which 21 consecutive periods from 1st to 21st horizontal scanning are used for receiving teletext. Therefore, if we take a margin and assume that channels whose periods 1 to 26 horizontal scans do not overlap can be received at the same time, on average about 4 channels can be received at the same time. When the number of channels is 6, channels can be switched a maximum of 6 times in one field, and therefore a maximum of 360 times in one second. This is fully possible using an electronic switch. The synchronization clock used to separate character signals from these received signals is controlled by the CPU 31 so that a synchronization clock suitable for each channel in the synchronization separation circuit 32 is used.

FIG. 12 is a flowchart illustrating the signal processing of this third embodiment. In step S1, the phase is measured from the synchronization signal of each channel as described above, and in step S2, the number of channels to be simultaneously received is determined. do. The number of channels is determined by taking into consideration whether all the programs of a certain channel are already stored on the magneto-optical disk 6, and if there is such a channel, excluding that channel, the maximum number of channels that can be received simultaneously is The number of channels is determined. Tuning demodulation in steps S3 to S5,
Character signals are separated and stored in the buffer memory 30. The processing in steps S3 to S5 is performed by changing channels by the number of channels that can be simultaneously received determined in step S2 in 1/60 seconds.

When the teletext signal stored in the buffer memory 30 has accumulated data up to the unit to be decoded, it is determined in step S6 whether the program of this data should be stored on the magneto-optical disk 6; If it is determined that storage is necessary, the process advances to step S7, and the teletext data is stored on the magneto-optical disk 6 as described above. After that, in step S8, the identification code of the program data is compared with the identification code of the corresponding channel in table (2), and if there is no match, the identification code is stored in table (2), and the program data If a program end code is included at the end of the program, the channel, identification code, and storage time are written in table (1). In this way, by receiving and storing teletext while simultaneously switching the channels to be received, the program contents of almost all programs on all channels can be stored in the storage area 6-2. By decoding the data on the storage area 6-2 and playing back the desired program at the desired time,
You can watch programs with almost no waiting time.

Note that the determination in step S6 is made as follows.

In the storage area 6-2, there is a table (table (1)) that stores the channels, identification codes, storage times, and content change flags of programs that have already been stored.
), and the work RAM 8 has a table (
There is a table (2)) and a table (table (3)) in which channels currently being received and stored are stored. In this way, the program number of the program data stored in the buffer memory 30 matches the channel and identification code on the table (1), the content change flag of the program data is the same, and the time preset by the user is the same as the previous time. If the memorized time has not passed, it is determined that the memorization is unnecessary; otherwise, it is determined that the memorization is necessary.

If it is determined that storage on the magneto-optical disk 6 is unnecessary, the process advances to step S9, and table (2)
The identification code of the corresponding channel above is compared with the identification code in the buffer, and if they match, the process proceeds to step S10 and the identification code in table (2) is deleted. After that, the process proceeds to step S11, and it is checked whether or not any program is stored in the corresponding channel on table (2). If no program is stored, the corresponding channel number on table (3) is deleted (step S12). . Next, the process returns to step S2 again, and the CPU 31 determines which channels can be simultaneously received except for that channel, and performs channel switching and reception processing.
) will be updated.

As explained above, according to this embodiment, by connecting a large-capacity, replaceable, and randomly accessible storage medium to a teletext receiver, a large number of teletext broadcasts can be transmitted over a long period of time. Programs can be memorized. Furthermore, this stored program can be played back and viewed whenever desired with almost no waiting time.

Furthermore, the image data stored in this manner can be stored for a long time, and by removing the storage medium from the apparatus and moving it, the storage data can be easily moved and the range of use can be expanded.

The present invention may be applied to a system made up of a plurality of devices, or to a device made up of one device. It goes without saying that the present invention can also be applied to cases where the present invention is achieved by supplying a system or device with a program that executes the processing defined by the present invention.

[0069]

As explained above, according to the present invention, a large number of TV teletext programs can be stored for a long period of time, and a desired program can be viewed at a desired time with almost no waiting time.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a teletext receiving apparatus according to a first embodiment of the present invention.

FIG. 2 is a conceptual diagram for explaining the operation of a teletext receiving apparatus according to a second embodiment of the present invention.

FIG. 3 is a block diagram showing a schematic configuration of a teletext receiving apparatus according to a third embodiment of the present invention.

FIG. 4 is a diagram illustrating a method of superimposing general teletext data on a television broadcast.

FIG. 5 is a diagram showing the structure of service identification data in general teletext broadcasting.

FIG. 6 is a diagram illustrating the structure of data within one horizontal scanning period in teletext;

FIG. 7 is a diagram for explaining the configuration of a buffer area of the magneto-optical disk according to the first embodiment of the present invention.

FIG. 8 is a diagram for explaining program data of a general teletext broadcast.

FIG. 9 is a diagram for explaining identification of teletext programs.

FIG. 10 is a diagram illustrating distribution of transmission of teletext programs transmitted in one horizontal scanning period into a plurality of programs.

FIG. 11 is a diagram for explaining how to switch channels in a third embodiment of the present invention.

FIG. 12 is a flowchart for explaining signal processing according to a third embodiment of the present invention.

[Explanation of symbols]

1 Antenna 2 Tuning/demodulation circuit 3 Synchronization separation circuit 4 Waveform/equalization circuit 5 Character signal separation circuit 6 Magneto-optical disk 6-1 Buffer area 6-2 Memory area 7,31 CPU 8 Work RAM 17 Buffer memory 33 Tuning demodulation phase measurement circuit

Claims (3)

[Claims] 1. A television receiver for teletext broadcasting capable of separating and displaying a character signal from a signal transmitted by character multiplexing, comprising: an extraction means for separating and extracting the character signal from a received signal; 1. A television receiver for teletext broadcasting, comprising: nonvolatile storage means for storing extracted character signals. 2. Storage areas of the storage means are divided into first and second storage areas.
The first area inputs and stores the character signal from the extraction means, and the character signal in the first area is determined to be the amount to be decoded or under conditions specified by the user. 2. The teletext multiplex broadcast receiving apparatus according to claim 1, wherein the character signal stored in the first area is transferred to the second area when the character signal matches the character signal. 3. Storage in the storage means is carried out sequentially from one physical or logical end of the storage medium of the storage means to the other end, and when the remaining capacity of the storage medium runs out, the Claim 1 characterized in that data is recorded while overwriting data already recorded from one end.
A teletext receiving device according to .