JPH10209982A - Fm multiplex signal receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an FM multiplex broadcasting receiver capable of displaying a latest program at all times without the need of making a user pay attention to a display screen and find an updated display page. SOLUTION: The carrier waves of FM multiplex broadcasting received by an antenna 12 are FM demodulated in an FM tuner part 14 and an FM multiplex decoding part 15 extracts FM multiplex signals and outputs them as digital signals. The CPU 40 of a personal computer 120 receives the output of the FM multiplex decoding part 15, detects whether or not display data are updated ones and displays images corresponding to the display data at a display part 24 only in the case that the display data are updated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an FM multiplex signal receiving apparatus, and more particularly to receiving information data divided and transmitted to a plurality of display unit data (page data) and outputting a predetermined number of display unit data. The present invention relates to an FM multiplex signal receiving apparatus having a function of transmitting received data by FM multiplex broadcasting.

[0002]

2. Description of the Related Art In recent years, as one of broadcasts providing new services, development and commercialization of FM multiplex broadcasting in which a digital signal is multiplexed and transmitted in a vacant spectral region of a baseband signal of FM stereo broadcasting has been advanced. Have been. FM
The multiplex broadcasting is a new medium that newly multiplexes a digital signal in a frequency band higher than the audio signal of the current FM stereo broadcast and broadcasts traffic information and text / graphic information.
These FM multiplex broadcasts are characterized by their effective use of frequencies, the simplicity of broadcast equipment, and the ability to easily receive traffic data and other information such as traffic information to vehicles such as automobiles. No.

[0003] Therefore, FM multiplex broadcasting is used as a means for transmitting real-time congestion information or the like to a vehicle equipped with a receiver or the like, or necessary information for a user having a handy type receiver is provided anytime and anywhere. As a means to provide an inexpensive transmission path that can be accessed,
Some commercialization has begun.

[0004] Before describing the configuration of a conventional FM multiplex broadcast receiving apparatus, an outline of the data structure in FM multiplex broadcast will be described first. In FM multiplex broadcasting, factors that deteriorate the reception state include multipath interference and fading interference. In particular, in the case of mobile reception, the transmission path characteristics are generally very poor.
Even in such a case, it is desirable to have a system that can receive signals completely at once. However, in actuality, there is a case where the data transmitted in one reception cannot be completely received, and in that case, it is assumed that the data to be retransmitted is received and the data that cannot be received is supplemented. .

It is desirable that the service area of FM multiplex broadcasting is equal to the service area of FM stereo broadcasting, but there are places in this service area where the average bit error rate exceeds 10 ^-2 . For this reason, the structure of the data to be transmitted has its error correction scheme and frame configuration determined in consideration of such poor transmission path characteristics. In particular, an error caused by an extremely low voltage due to fading interference is fatal, and error correction may not be possible. Therefore, by adjusting the unit data length of the transmitted data to the average burst length of the error caused by fading, if an error that cannot be corrected occurs, the data is retransmitted for each of the unit data described above. It can be complemented by replacing with unit data.

Further, in FM multiplex broadcasting, a product code in which two block codes are orthogonally arranged is used as an error correction method because of its high error correction effect. Therefore, the data has a two-dimensional frame structure including an error correction code in both the vertical and horizontal directions.
The transmission data has a data structure having a hierarchical structure with the data in one frame as a basic unit.

[0007] As a specific example of the above-mentioned description, a document (Proc. Of Vehicle Navigation & Information Sy
The FM multiplex broadcasting system disclosed in the Stems Conference (1994) A4-2 pp. 111-116 will be described.

FIG. 8 is a diagram showing specifications of the above-mentioned data hierarchical structure. Referring to FIG. 8, in layer 1, transmission path characteristics are specified. In addition to the L + R signal and the LR signal, which are ordinary FM stereo broadcast signals, a multiplex signal is superimposed on a higher frequency side than the LR signal. This superposition method controls the level of a multiplexed signal by the degree of modulation of the LR signal in consideration of the fact that the interference from the multiplexed signal to the audio signal becomes significant when the degree of audio modulation is small.
(Level controlled Minimum Shift Keying) method is adopted.

The layer 2 defines a data frame structure including an error correction method. Each frame has 27 columns
It consists of two blocks, and has a 16-bit BIC (Bl
ockIndentification Code) is added, and frame synchronization and block synchronization are performed based on the BIC. Of the 272 blocks in the column direction, 190 blocks are packets for transmitting data, and 82 blocks are parity packets for transmitting parity in the column direction. Each packet has a 176-bit information portion in the row direction and a 16-bit CRC (Cyclic Redundancy Cod) as an error correction code.
e) and an 82-bit parity part. In other words, transmission data is based on this one frame as a basic unit.
At this stage, error correction is first performed.

[0010] Layer 3 defines the structure of a data packet. The data packet is BI out of each row in the frame.
It consists of 176 bits excluding C, CRC and parity. Further, this data packet is composed of a prefix and a data block. The prefix includes information for identifying the contents of the data, and specifies, for example, which program contents described below the data packet belongs to.

[0011] Level 4 defines the structure of a data group. A data group is composed of one or more data blocks. That is, based on the information in the prefix in the data packet, the data packet numbers are arranged in the order of the data packet numbers from "0" to the data blocks with the information output flag in the prefix. This data group includes a CRC which is an error correction code, and transmission data is subjected to error correction also in this layer. One data group corresponds to one display unit, that is, one page of data.

Layer 5 is transmitted by FM multiplex broadcasting.
It defines the structure of a group of information data, that is, program data.

FIG. 9 shows the structure of the program data. In FIG. 9, a program of character and graphic information is composed of a plurality of data groups, and the first data group is coded information relating to the entire program such as a program number and the total number of pages as program management data. Following the program management data, there are a plurality of page data, and the data for each page is encoded. The program data and the page data include a program data header section and a data unit group.

The data unit group is composed of a plurality of data units, such as a character data section and a photographic graphic data section, which are divided for each encoding. That is, in the data structure described above, the program data on the receiving side forms a group of data indicating one set of information. For example, in the case of traffic information, the program information indicates the congestion status at each junction of a specific route (such as an expressway), and in the case of a weather forecast, it indicates weather forecast information in a specific area.

FIG. 10 is a schematic block diagram showing the configuration of a conventional FM multiplex broadcast receiver 10. As shown in FIG. In FIG. 10, FM received by antenna 12 and tuner 14
The multiplex broadcast signal is detected by a detection circuit 16, and further supplied to an LMSK demodulation circuit 20 via a band pass filter 18. The LMSK demodulation circuit 20 demodulates the data of the FM multiplex broadcast signal which has been subjected to the LMSK modulation, and extracts the FM multiplex signal. The demodulated data signal is supplied to the synchronous reproduction circuit 22.
, The frame synchronization and the block synchronization are performed based on the BIC as described in the layer 2 of FIG. The synchronized data signal is error-corrected in the error correction circuit 24 based on the parity code and the CRC.

Therefore, the FM multiplex broadcast packet data (packet data having the configuration shown in layer 3 in FIG. 8) which has been normally received or error corrected is output from the error correction circuit 24.

A central processing unit (hereinafter referred to as a CPU) 40 extracts data blocks, reconstructs data groups, corrects errors at the data group stage, and regenerates program data into inputted packet data. After performing the configuration, the program data is output to the display device 42. The display device 42 outputs the input program data as graphics or characters. Here, a liquid crystal screen or the like having a display area for one page, that is, 248 × 60 dots (corresponding to 15.5 characters × 2.5 lines in Japanese display) is used as the display device 42.

The display device 42 has a special liquid crystal,
It is conceivable to use a display screen of a computer.

FIG. 11 is an external view showing one example. The system shown in FIG. 11 shows a case where program information is displayed on the screen of the notebook computer 120 by using the PC card type receiver 21 for the notebook computer 120. FIG. 12 shows an example of the program display at that time. In FIG. 12, in order to read the text displayed on the screen, it is necessary for the user to perform a mouse operation or the like to scroll the displayed program up and down to find a desired program.

In order to eliminate the inconvenience of the operation, as shown in FIG. 13, a method has been considered in which the program contents are displayed on a screen and characters are displayed so as to flow from right to left. That is, first, as shown in FIG. 13 (a), the beginning of the data starts to be displayed on the right side of the displayed window, and the first displayed character moves to the left as time passes. As shown in FIG. 13B, the next character is displayed on the right side. As a result, FIG.
As shown in FIG. 3C, the display data is displayed so as to flow from right to left. By displaying in this manner, the user can browse the program without having to operate a mouse or the like to view the program contents.

[0021]

However, the use of the latter display method has the following problems. That is, the user must pay attention to the displayed data even though the displayed data is old and has already been read, and pays attention to the program contents while performing other operations. Becomes very complicated. Another disadvantage is that the user has to wait until the new data is displayed, even though the user wants to read the new data immediately.

Therefore, a main object of the present invention is to provide an FM multiplex broadcast receiving apparatus capable of always displaying the latest program without the need for the user to watch the display screen to find an updated display page. It is.

[0023]

The invention according to claim 1 is
In an FM multiplex communication system in which each of a plurality of information data to be transmitted is divided into a plurality of display unit data and transmitted,
Each display unit data is an FM multiplex signal receiving apparatus that receives transmission data including program update data indicating whether or not the content has been updated, and receives a carrier wave that transmits the display unit data by FM multiplex transmission, and Demodulation means for demodulating,
FM multiplex signal decoding means for receiving the output of the demodulation means, extracting the FM multiplex signal, and outputting the signal as a corresponding digital signal, and receiving the output of the FM multiplex signal decoding means, the display data of each of the currently displayed data is displayed. A program update detecting means for detecting whether or not the program has been updated; and a display means for outputting an image corresponding to the display data only when display data is updated in response to an output of the program update detecting means. It is comprised including.

In the invention according to claim 2, the display means of claim 1 keeps displaying the last displayed program data unless a new program update is detected.

In the invention according to claim 3, the display means of claim 1 does not display the program data unless a new program update is detected.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of the present invention.
1 is a schematic block diagram illustrating a configuration of an M multiplex broadcast receiving device 100. In FIG. 1, FM multiplex broadcast receiving apparatus 100
Includes an antenna 12 for receiving FM radio waves, an FM tuner section 14 for receiving the output of the antenna 12 and performing FM demodulation;
An FM that receives an output of the tuner unit 14, extracts an FM multiplex signal, corrects an error, and outputs a corresponding digital signal.
It includes a multiplex decoding unit 15 and a personal computer 120 that receives the digital signal, forms display unit data (page data), and displays corresponding characters and the like.

The FM multiplex broadcast receiving apparatus 1 shown in FIG.
00 is different from the conventional FM multiplex broadcast receiving apparatus 10 shown in FIG.
The FM multiplex decoding section 15 extracts an FM multiplex signal from the M-demodulated signal, receives the digital signal output as packet data by the personal computer 120, reconstructs the packet data into program data, and displays the program data. Is a point. That is, the FM multiplex broadcast signal received by the antenna 12 is synchronously detected by a local oscillation wave output from a phase locked loop circuit 4 (hereinafter, referred to as a PLL circuit) in an FM demodulation circuit 2 in an FM tuner section 14, F via buffer 6
It is output to the M multiplex decoding unit 15.

The FM multiplex decoding section 15 receives the FM-demodulated signal via the buffer circuit 8, extracts a signal component in a predetermined frequency region by the band-pass filter 18, performs LMSK demodulation in the demodulation LSI 20,
Extract M multiplex signals. The CPU 26 controls the demodulation LSI 20
, Block synchronization of received data, error correction, etc., are performed and output as packet data. At this time, if there is uncorrectable packet data,
The data is deleted in the CPU 26, and only the data necessary for display is selected and output.

The RAM 28 operates as a buffer for receiving data from the CPU 26 and outputting data to the interface 30. The address decoder 32
When the PU 26 detects that the personal computer 120 has been accessed, it causes the interface 30 to output data. Controller 34 normally receives output data from interface 30 and outputs data to personal computer 120. However, when the apparatus is started up, initialization between the interfaces is performed based on data stored in the ROM 36.

The personal computer 120 receives the packet data output from the FM multiplex decoding unit 15 via the interface 38. The CPU 40 receives the output data from the interface 38, that is, the packet data, extracts a data block from the data packet according to the hierarchical structure shown in FIG. 8, reconstructs a data group from the data block, and performs error correction on the data group. Perform Further, the CPU 40 extracts a data header and a data unit group corresponding to page data from the data group data in the data group, and reconstructs the program data.

Here, for example, in a hand-held personal computer, a liquid crystal flat panel display or the like is used as the display section 42, and its display area is 640.
It has a resolution of × 400 dots or more.

Next, the operation of the FM multiplex broadcast receiving apparatus 100, particularly, the operation of the CPU 40 will be described. Personal computer 120 in FM multiplex broadcast receiving apparatus 100
Before describing the operation of the CPU 40 in the above, the data structure of the FM multiplex broadcast signal as a premise thereof will be described in detail in advance.

FIG. 2 is a schematic diagram showing the structure of a data group including the program management data shown in FIG. In the configuration of the data group shown in FIG. 2, the program management data is included in the data group data. The data group includes, at the head thereof, a heading start signal (SOH) indicating the start of the data group, followed by a data group link code which is a flag indicating the presence or absence of connection of the data group, and indicating the number of bytes of the data group data. Includes data group size data. Following that,
There is data group data which is the main body of data to be transmitted. Subsequently, a NULL area for length adjustment for adjusting the data group length to an integral multiple of the data block, an end code indicating the end of the data group, and a CRC code for performing error detection of the data group Exists.

FIG. 3 is an example of a schematic diagram showing the structure of a data group corresponding to the first program management data in the program data shown in FIG. 2 in more detail. As described with reference to FIG. 2, the heading start signal (SOH) exists in the first data block DB1, and the data group link code (DGL) and the data of the data group size exist in the subsequent data blocks DB2 and DB3. The data group link code and the data group size are called a data group header. Thereafter, an information separation code (RS) and a data header parameter follow, and the substantial contents of the program data header in the program management data start from the data block DB6. The program data header includes update data indicating that a program number or program content has been updated, the total number of pages included in the program,
The display format data for specifying the display format of the program is included. After the program data header in the program management data, a data unit group including characters and graphic data follows.

On the other hand, in each page data following the program management data, a page data header is present at the head and includes data such as a program number, a page number in the program of the page, and a display format. Also in the page data, a data unit group including character / graphic data follows the page data header. Therefore, the configuration is such that data relating to the page number of the page is included for each data group corresponding to each page data.

FIG. 4 is a diagram showing the details of the data structure of hierarchy 3 data. The CPU 40 determines, for each page data,
Each time a data packet of layer 3 shown in FIG. 4 is received, it is checked whether or not the program has been updated. Inside the prefix in FIG. 4, there is an update flag indicating whether or not the program has been updated, in addition to information for distinguishing the program such as service identification. The update flag is set to “00”, “01”, “1” every time the program is updated.
"0", "11", and "00" are displayed to indicate that there has been an update. Therefore, by monitoring this flag, it can be determined whether or not the program has been updated.

FIG. 5 is a diagram showing a flowchart at that time. In FIG. 5, the update flag is read to determine whether or not it is the same as the current flag value. If not, it is determined that the program has been updated, and the program display means is notified of the update. Receive the data of the changed program and display it. By checking the presence or absence of this update for all program data, all updated programs are displayed on the screen. Therefore, the user can browse all the latest information without any operation.

Although the display mode of the program has already been described with reference to FIG. 13, such a display method can be used as a screen saver for a screen, for example. A screen saver displays an image that constantly moves and moves on the screen when there is no operation on the computer for a certain period of time so that the screen does not burn on a CRT or the like. It is a technique to avoid it. If the display as shown in FIG. 13 is performed when the screen saver operates, an image in which only characters flow on the screen can be observed. Such a display is optimal for a screen saver.

Several methods are conceivable for the display form after the display of a new program is completed. FIG. 6 is a flowchart showing the first method. In this first method,
Unless a new program change is detected, the program data is kept displayed. That is, if the program is not updated, the current program content is displayed again.
As a result, the user can always read only the latest program, and does not need to see the program that has already been read.

FIG. 7 is a flowchart showing the second method. In the second method, if a program change detection is not performed, a changed program is displayed, and then a new program is not displayed. This allows the user to recognize that the displayed data is always the latest. At this time, in order to prevent the user from overlooking the program, a display method of stopping the display after displaying the latest program a plurality of times is also possible.

In the present invention, the main purpose is to detect a program update and change the program display mode, and the display method is not limited to the above two methods. .

[0042]

As described above, according to the present invention, it is detected whether or not the display data is an update of the currently displayed data, and the display data is displayed only when the display data is updated. Is output, the user receiving the FM multiplex broadcast can always read the latest program, and there is no need to look at the display screen and find the updated display page. Further, there is no need to perform any operation for searching for the latest page.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an FM multiplex broadcast receiving apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing a configuration of a data group in an FM multiplex broadcast signal.

FIG. 3 is a schematic diagram showing a configuration of a page data header in page data.

FIG. 4 is a diagram showing a detailed configuration of a prefix of FM multiplexed data in layer 3;

FIG. 5 is a flowchart illustrating an operation of program update detection according to an embodiment of the present invention.

FIG. 6 is a flowchart illustrating an operation of displaying a program according to an embodiment of the present invention.

FIG. 7 is a flowchart showing another example of program display.

FIG. 8 is a schematic diagram showing specifications of FM multiplex broadcasting.

FIG. 9 is a schematic diagram showing a configuration of program data.

FIG. 10 is a schematic block diagram showing a configuration of a conventional FM multiplex broadcast receiving apparatus.

FIG. 11 is a schematic diagram showing the appearance of a conventional FM multiplex broadcast receiving apparatus.

FIG. 12 is a diagram showing an example of a display method of FM multiplex data.

FIG. 13 is a diagram showing another example of a display method of FM multiplex data.

[Explanation of symbols]

 2 FM demodulation circuit 4 PLL circuit 6.8 buffer circuit 18 Band pass filter 20 NMSK demodulation circuit 26 CPU 28 RAM 30, 38 Interface 32 Address decoder 34 Controller 36 ROM 40 CPU 42 Display unit 44 Memory 100 FM multiplex broadcast receiver

Claims (3)

[Claims] 1. An FM multiplex communication system in which each of a plurality of information data to be transmitted is divided into a plurality of display unit data and transmitted, wherein each of the display unit data indicates whether or not the content has been updated. What is claimed is: 1. An FM multiplex signal receiving apparatus for receiving transmission data including update data, comprising: a demodulation means for receiving a carrier transmitting the display unit data by FM multiplex transmission and performing FM demodulation; FM multiplex signal decoding means for extracting a multiplex signal and outputting it as a corresponding digital signal; and receiving the output of the FM multiplex signal decoding means, each of the display data is an updated version of the currently displayed data. A program update detecting means for detecting whether or not the display data is updated when the display data is updated in response to the output of the program update detecting means. And display means for outputting an image, FM multiplex signal reception apparatus. 2. The FM multiplex signal receiving apparatus according to claim 1, wherein said display means keeps displaying the last displayed program data unless a new program update is detected. 3. The FM multiplex signal receiving apparatus according to claim 1, wherein said display means does not display program data unless a new program update is detected.