JP3671987B2 - FM teletext receiver - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a receiver for receiving text multiplex broadcasting.
[0002]
[Prior art]
In FM broadcasting, it is called “FM text multiplex broadcasting”, and it is realized that data such as text information is multiplexed and transmitted together with the original audio broadcasting program. Also, FM receivers that receive the FM character multiplex broadcast and can display character information on a display element such as an LCD (Liquid Crystal Display Element) have come to the market.
[0003]
This FM character multiplex broadcasting is mobile reception and is called DARC system. The standard for multiplexing digital data such as character information is 76 kHz subcarrier frequency, 16 kbit / s transmission rate, and LMSK modulation system. The error correction method is a product code using a (272,190) shortened difference set cyclic code.
[0004]
The program services such as character information are classified into levels 1, 2, and 3. These all present (display) character information etc. by dot display, but level 1 is a service for receivers that can display 15.5 characters x 2.5 lines including the header part. Information is characters. Level 2 is a service for a receiver capable of displaying 15.5 characters × 8.5 lines including a header portion, and information is characters and figures. Further, level 3 is a traffic information service for a receiver that can display a detailed map on a CD-ROM or the like, that is, a navigation system.
[0005]
As level 1 program services, news, weather forecasts, traffic information, entertainment, main complementary programs, and the like are considered. In this case, entertainment provides fortune telling, listener message boards, quizzes, town information, and the like.
[0006]
The main supplementary program provides supplemental information of the program such as the name of the song, the name of the performer, the telephone number / fax number at the time of the request when the original audio broadcasting program is a music program, for example. It is. In the following, the main complementary program is referred to as “program information” or “program linkage”.
[0007]
Furthermore, “emergency information” provided as needed when there is an urgent need is considered as a program service other than the above.
[0008]
FIG. 4 shows a frame structure of the LMSK signal multiplexed in the FM character multiplex broadcasting. One frame of the LMSK signal is composed of 272 blocks, and each block has 288 bits.
[0009]
One frame is divided into 190 data packet blocks and 82 vertical parity packet blocks, and the vertical parity packet blocks are distributed and transmitted.
[0010]
A 16-bit BIC (Block Identification Code) is added to the head of each block. However, four types of BICs are used, whereby each parity packet is distinguished and the head of the frame is identified.
[0011]
The block of data packets has a 176-bit data packet following the BIC, followed by a 14-bit CRC code, followed by an 82-bit horizontal parity check code.
[0012]
In this case, the CRC code is added to detect a residual error after error correction by the product code. Further, the vertical parity packet block has a 272-bit vertical parity packet following the BIC.
[0013]
Further, as shown in FIG. 5, each data packet is composed of a 32-bit prefix followed by a 144-bit data block.
[0014]
As shown in FIG. 6, this prefix includes a service identification code, a decoding identification flag, an information end flag, an update flag, a program number, a page number, a data link code, and a data packet number.
[0015]
The service identification code is 4 bits and identifies the program content. For level 1, “1” is general information for sequential reception processing, “2” is general information for recording reception processing, and “4” is traffic information.
[0016]
In this case, the sequential reception process is a mode in which the decoding process of presentation is started as soon as the first data packet of program data or page data arrives at the receiver, and the record reception process is the program data or page data. This is a mode in which the presented decoding process is started for the first time after receiving and recording all data and performing error correction processing using a CRC code for each data group.
[0017]
For programs that need to be presented at the receiving side on the transmitting side, or programs that cannot be presented in time when the decoding process is started after the final packet of the data group is obtained, Is done.
[0018]
The decoding identification flag is 1 bit, and is set to “1” when the error correction circuit of the receiver outputs data by decoding only in the horizontal direction. When the data is output after combining the horizontal and vertical directions. Is set to “0”.
[0019]
In the sequential reception process, when the decoding identification flag is “0”, the receiver receives the first BIC of each data packet, and at the time of the first BIC of the data packet after 302 packets, It is stipulated to perform a decoding process for presenting each data packet.
[0020]
The information end flag is 1 bit, and is set to “1” when a data group transmitted with a certain data group number is ended, and is set to “0” otherwise. Furthermore, the update flag is 2 bits and is incremented by 1 each time the data group is updated. The program number is 8 bits, the page number is 6 bits, and a data group number is formed by both.
[0021]
Furthermore, the data link code is 2 bits, and data that should belong to one data group is a large amount of data such that the number of packets exceeds the maximum value of the data packet number. This is a code that links data groups in the order of 0 → 1 → 2 → 3 when divided into groups and transmitted by the same data group number with different data link codes.
[0022]
The data packet number excluding the data link code is 8 bits and is assigned in order from “0”.
[0023]
Furthermore, the program number is from 0 to 255, “0” is assigned “total table of contents”, “254” is assigned to the main complementary program (program information or program linkage), and “255” is assigned to emergency information. Are assigned respectively.
[0024]
The page number is from 1 to 62, that is, one program has a maximum of 62 pages. One page corresponds to one data group, and one data group includes one or a plurality of data blocks.
[0025]
In level 1, one page generally has a display format of 15.5 characters × 2.5 lines, but can also be a display format of 15.5 characters × 8.5 lines. In this case, the character data designates a character to be displayed by a JIS code.
[0026]
As described above and as shown in FIG. 7, the receiver corresponding to level 1 is, for example, an LCD 1 having a display screen 1a capable of displaying 15.5 characters × 2.5 lines. However, in the display screen 1a, the lower left 15 character × 2 line portion 1b is the text display area, and the upper 0.5 line and the right 0.5 character part 1c with hatching are the header text display area. The
[0027]
The receiver receives the LMSK signal together with the stereo composite signal, decodes the character data from the LMSK signal, and writes it into the buffer memory.
[0028]
Further, the receiver or the remote control transmitter for remotely controlling the receiver is provided with a “total table of contents” key. By operating this key, the receiver displays the display screen 1a as shown in FIG. The total table of contents (main menu) is presented. However, FIG. 8A shows a state in which the total table of contents is displayed on a plurality of pages or in a display format of 8.5 lines, and the first one of them or the first 2.5 lines is displayed.
[0029]
Further, the receiver or the remote control transmitter is further provided with a “page (screen) advance” key, and by operating this key, as shown in FIG. Or the next two lines of the 8.5-line display page.
[0030]
When the user selects and determines the number of the item to be viewed from the total table of contents, the table of contents for the selected and determined item is further presented. For example, when the user selects “3. Weather forecast” from the total table of contents, a table of contents such as “1. Today's weather” and “2. Tomorrow's weather” is presented as shown in FIG. .
[0031]
Furthermore, when the user selects and determines the number of the item to be viewed from the table of contents, the first page for the selected and determined item is presented. For example, when the user selects “1. Today's weather” from the above table of contents, as shown in FIG. 10, specific character information about “Today's weather” is presented.
[0032]
[Problems to be solved by the invention]
By the way, when FM character multiplex broadcasting is performed in the sequential reception mode, the page (display screen) is automatically generated at intervals of about 5 to 10 seconds without the user performing key operations for page switching. Will be switched.
[0033]
However, when pages are automatically switched, for example, when an FM receiver is mounted on a car, the driver may miss information (screen) intended. However, paying attention to the display screen so as not to miss it is not preferable for driving an automobile.
[0034]
The present invention is intended to solve such problems.
[0035]
[Means for Solving the Problems]
In this invention,
Each time the first data packet of program data or page data arrives, decoding is started, and character data for the sequential reception processing mode that automatically updates the display screen at predetermined intervals is multiplexed with the audio broadcast program. A receiver for receiving FM character multiplex broadcasts,
A receiving circuit for receiving the FM character multiplex broadcast;
A decoder circuit that decodes and outputs the character data from the output signal of the receiving circuit ;
A memory to which the character data decoded by the decoder circuit is supplied ;
A display controller that converts character data stored in the memory into a display signal;
A display element that is supplied with a display signal converted by the display controller and displays a corresponding character or the like ;
A key for controlling the display of the display element ;
When the key is operated while character data is being received in the sequential reception processing mode, if the memory contents are allowed to be updated with the decoded character data, the update is performed. Ban,
When the contents of the memory are prohibited from being updated with the decoded character data , the FM character multiplex broadcast receiver is allowed to update .
[0036]
[Action]
When the key is operated, even in the sequential reception mode, updating of the contents of the display memory is prohibited and display updating is prohibited.
[0037]
【Example】
FIG. 1 shows an example of a signal system when the present invention is applied to an in-vehicle FM receiver. This FM receiver is assumed to have level 1 reception capability for FM teletext broadcasting.
[0038]
That is, the FM signal received by the antenna 11 is supplied to a synthesizer-type tuner circuit 12 to select a broadcasting station having a target frequency, and the FM signal is converted into an intermediate frequency signal. The signal is supplied to the FM demodulation circuit 14 through the intermediate frequency amplifier 13.
[0039]
Thus, the demodulating circuit 14 adds the stereo left and right channel audio signals L and R (L + R), the DSB signal balanced-modulated by the difference signal (LR), the pilot signal, and the above-described signal. A frequency-multiplexed signal with the LMSK signal in the FM character multiplex broadcasting is extracted.
[0040]
Then, this frequency multiplexed signal is supplied to the stereo demodulation circuit 15, and audio signals L and R are demodulated from the addition signal (L + R) and the DSB signal, and these signals L and R are transmitted through the amplifiers 16L and 16R to the left and right channels. Supplied to speakers 17L and 17R.
[0041]
Further, the FM receiver is provided with a microcomputer 20 for executing channel selection in the tuner circuit 12 and displaying characters by FM character multiplex broadcasting.
[0042]
That is, the microcomputer 20 includes a CPU 21 for executing a program, a ROM 22, a work area RAM 23, and an FM character multiplex broadcast data reception buffer RAM 24. In this case, the ROM 22 is written with data for displaying various routines and a predetermined character string (sentence), and as a part of the routine, for example, the display control routine 100 shown in FIG. 2 and FIG. And a display update routine 200 is provided.
[0043]
These memories 22 to 24 are connected to the CPU 21 through the system bus 29, and interface circuits (ports) 25 to 28 are connected to the bus 29.
[0044]
Then, data for channel selection is supplied from the interface circuit 25 to the tuner circuit 12, and the channel selection is executed. Further, the demodulated signal from the demodulating circuit 14 is supplied to the decoder circuit 41, and the data in the FM character multiplex broadcasting is decoded and extracted from the LMSK signal. This data is written into the RAM 24 through the interface circuit 26, and the data in the RAM 24 is , Always updated with the latest data.
[0045]
The interface circuit 27 is connected to various operation keys 42 constituted by non-lock type push switches, and the key outputs are taken into the microcomputer 20. Thus, when any key of the keys 42 is pressed, the pressed key is determined by the CPU 21, and processing corresponding to the pressed key is executed.
[0046]
However, when the FM receiver is in-vehicle, the operation panel is narrow and a large number of operation keys cannot be arranged. Therefore, in this example, the key 42 is a frequently operated key and highly important. Only the keys are used, and other operations are performed by a remote controller (remote operation).
[0047]
For this reason, the interface circuit 27 is also connected to a receiving circuit 43 of a remote controller. In this example, the remote control is an infrared type, and the receiving circuit 43 includes a light receiving element that receives infrared light from the transmitter 60 of the remote control and a decoder circuit that decodes a remote control signal from the light receiving element. And have.
[0048]
The remote controller transmitter 60 is also provided with various operation keys 62 (62A to 62N) configured by non-lock type push switches. A part of the key 62 has the same function as that of the key 42. However, when any key of the keys 62 is pressed, data corresponding to the pressed key is formed, which is converted into infrared rays and is converted into an FM receiver. Sent to.
[0049]
Then, in the FM receiver, the original data is taken out even if the infrared ray transmitted from the transmitter 60 is received by the receiving circuit 43, and this data is supplied to the interface circuit 27. In this way, the process corresponding to the pressed key is executed by the microcomputer 20 when the key 62 is pressed in the same manner as when the key 42 is pressed. In the following, the operation of each unit will be described based on the case where the key 62 of the transmitter 60 is used.
[0050]
The interface circuit 28 is connected to a beep sound signal forming circuit 44, and the beep sound signal is supplied to the amplifiers 16L and 16R.
[0051]
Furthermore, a font ROM (character generator) 31 having font data for converting character codes sent by FM character multiplex broadcasting into display data is connected to the bus 29, and a display memory 32, A display controller 33 is connected to the controller 33, and for example, an LCD 50 is connected as a display element.
[0052]
In this case, in this example, the LCD 50 is configured in the same manner as the LCD 1 described above, and has a display capability of 15.5 characters × 2.5 lines. The memory 32 is a bit map method corresponding to the dot display method of the LCD 50 and has a capacity for one screen. In the following, the teletext program is performed at level 1, and one page has the size (capacity) of one screen.
[0053]
The character code held in the RAM 24 is read by the CPU 21, the read character code is converted into display data using the font data in the ROM 31, and the display data is written in the memory 32. . At this time, the display data in the memory 32 is repeatedly read out by the controller 33, converted into a display signal, and supplied to the LCD 50. Therefore, the character of the character code read from the RAM 24 by the CPU 21 is displayed on the LCD 50.
[0054]
In such a configuration, when the display key 62A of the keys 62 (or 42) is pressed in the sequential reception mode, the routine is executed by the CPU 11 each time the key is pressed, and pages are automatically switched in the sequential reception mode. Is permitted or prohibited.
[0055]
That is, when information by FM character multiplex broadcasting is displayed, when the display key 62A is pressed, the processing of the CPU 11 starts from step 101 of the routine 100, and then the display fixing flag SCRF is checked at step 102. The This flag SCRF permits switching of the page displayed on the LCD 50 by the routine 200 when it is “0”, and prohibits it when it is “1”.
[0056]
When SCRF = "0", the process proceeds from step 102 to step 103. In step 103, SCRF = "1" is set, and thereafter, in step 104, the routine 100 is terminated.
[0057]
In step 102, when SCRF = “1”, the process proceeds from step 102 to step 111. In step 111, SCRF = “0” is reset, and then the process proceeds to step 112. In step 112, the latest page of the currently selected character multiplex program is displayed on the LCD 50.
[0058]
As described above, this display is performed by using the font of the ROM 31 to display the latest page data (character code) of the selected program among the text broadcast data stored in the RAM 24. This display data is realized by being written into the memory 32.
[0059]
Accordingly, when the display key 62A is pressed while SCRF = “1” and the page is fixed, the latest page of the selected program is displayed at that time. Thereafter, the process proceeds to step 104, and this routine is terminated.
[0060]
On the other hand, in the case of the sequential reception mode, the RAM 24 prepares page data to be displayed, and when a new screen display request is made, the CPU 200 executes the routine 200 and performs display according to the flag SCRF.
[0061]
That is, when a display update is requested, the processing of the CPU 11 starts from step 201 of the routine 200. Next, in step 202, the flag SCRF is checked.
[0062]
When SCRF = "0", the process proceeds from step 202 to step 203. In this step 203, the data prepared in the RAM 24 is converted into display data using the font data of the ROM 31, and then stored in the memory 32. Written. Thereafter, in step 204, this routine 200 is terminated.
[0063]
Accordingly, when SCRF = “0”, a new page is displayed on the LCD 50 each time a display update is requested.
[0064]
However, when SCRF = “1” in step 202, the process proceeds from step 202 to step 204, and this routine 200 is terminated.
[0065]
Therefore, when SCRF = “1”, even if a display update is requested, the memory 32 is not rewritten. Therefore, the display on the LCD 50 remains when the key 62A is pressed, and the display is fixed.
[0066]
The flag SCRF is inverted between “0” and “1” every time the display key 62A is pressed. Therefore, even in the sequential reception mode, the display update is prohibited by pressing the key 62A. be able to. It is also possible to cancel the prohibition of updating the display and permit the update.
[0067]
Thus, according to the FM receiver, even when the text multiplex broadcasting is broadcast in the sequential reception mode, switching of the page displayed on the LCD 50 can be prohibited by operating the key 62A. Accordingly, when necessary information is displayed, even if there is no time to read all the displayed information for some reason, the displayed screen is fixed by operating the key 62A. Information can be seen.
[0068]
In particular, when the car is being driven, the screen can be fixed, so that it is possible to prevent the attention of the screen from being deprived of attention.
[0069]
When there is no key input for updating the display when the mode is not the sequential reception mode, the routine 200 is executed when the display is automatically updated at a predetermined time interval. By doing so, it is possible to switch permission or prohibition of the update with the key 62A.
[0070]
In the above description, various operations can be performed by the remote controller. However, all of these operations can be performed from the key 42 of the FM receiver. In that case, the remote control function may not be provided. In addition, when FM character multiplex broadcasting is level 2, one screen has 8.5 lines, and 8 lines of which are the text display area. The above processing may be performed by regarding the page as one page.
[0071]
【The invention's effect】
According to the present invention, even when the text multiplex broadcasting is broadcast in the sequential reception mode, switching of the displayed page can be prohibited by operating the predetermined key. Therefore, when necessary information is displayed, even if there is no time to read all the displayed information for some reason, it is displayed by fixing the displayed screen by operating the keys. You can see the information you have.
[Brief description of the drawings]
FIG. 1 is a system diagram showing an example of the present invention.
FIG. 2 is a flowchart showing an example of the present invention.
FIG. 3 is a flowchart showing an example of the present invention.
FIG. 4 is a diagram for explaining a signal format;
FIG. 5 is a diagram for explaining a signal format;
FIG. 6 is a diagram for explaining a signal format;
FIG. 7 is a diagram for explaining a display screen.
FIG. 8 is a diagram for explaining a display screen;
FIG. 9 is a diagram for explaining a display screen;
FIG. 10 is a diagram for explaining a display screen.
[Explanation of symbols]
12 tuner circuit 13 intermediate frequency amplifier 14 FM demodulation circuit 15 stereo demodulation circuit 20 microcomputer 21 CPU
22 ROM
23 RAM (for work area)
24 RAM (for receive buffer)
31 Font ROM (character generator)
32 memory (for display)
33 Display controller 41 Decoder circuit 42 Operation key 43 Receiver circuit (for remote control)
44 Formation circuit (for beep signal)
50 Display element 60 Transmitter (for remote control)
62 Operation key 100 Display control routine 200 Display update routine

Claims (1)

Each time the first data packet of program data or page data arrives, decoding is started, and character data for the sequential reception processing mode that automatically updates the display screen at predetermined intervals is multiplexed with the audio broadcast program. A receiver for receiving FM character multiplex broadcasts,
A receiving circuit for receiving the FM character multiplex broadcast;
A decoder circuit that decodes and outputs the character data from the output signal of the receiving circuit ;
A memory to which the character data decoded by the decoder circuit is supplied ;
A display controller that converts character data stored in the memory into a display signal;
A display element that is supplied with a display signal converted by the display controller and displays a corresponding character or the like ;
A key for controlling the display of the display element ;
When the key is operated while character data is being received in the sequential reception processing mode, if the memory contents are allowed to be updated with the decoded character data, the update is performed. Ban,
An FM character multiplex broadcast receiver that permits updating when the contents of the memory are prohibited from being updated by the decoded character data .

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