JPH08298500A - Data transmission system - Google Patents

Abstract

PURPOSE: To provide a data transmission system with a high communication success rate even on the occurrence of random noise. CONSTITUTION: A transmitter 3 converts '1' into a 1st 3-bit string, converts '0' into a 2nd 3-bit string with a longest hamming distance from the 1st 3-bit string and converts digital information to be sent by 1st and 2nd conversion means and the converted information is sent to a receiver 7. The receiver 7 divides the digital information sent from the transmitter 3 by each 3-bit and corrects the information divided into 3-bit each while referencing the 1st 3-bit string and the 2nd 3-bit string and converts the information into '0' or '1' codes.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data transmission system for transmitting digital data.

[0002]

2. Description of the Related Art Recently, a transmitter has been connected to a gas alarm,
A system has been developed in which a receiver is connected to a microcomputer meter, and when a gas alarm detects a gas leak, a transmitter sends an alarm signal to the microcomputer meter through the receiver to shut off gas.

This alarm signal (telegram) is a signal in which a CRC code is added to the ID number and time information of the receiver, and the receiver side performs error detection by the CRC code. Therefore, if even one bit is incorrect, the message itself becomes invalid. Therefore, the same message is retransmitted 66 times at one transmission timing in order to suppress the deterioration of the communication success rate.

[0004]

However, if an error is detected in even one bit in the telegram, the telegram will be discarded. Therefore, if random noise such as carrier noise occurs, all telegrams will be invalid and the communication will be lost. There is a problem that there is a high possibility that it will end in failure.

The present invention has been made in view of such a problem, and an object thereof is to correct a message without invalidating a message in which an error is detected even if random noise or the like occurs. It is to provide a data transmission system capable of improving the communication success rate.

[0006]

In order to achieve the above-mentioned object, according to the present invention, a transmitting side includes a first converting means for converting "1" into a first N (N is an odd number) bit string, and " 0 "is the second N having the longest Hamming distance with the first N-bit string.
The receiving side comprises: a second converting means for converting into a bit string; and a means for converting the digital information to be transmitted by the first converting means and the second converting means and transmitting it to the receiving side. Means for dividing the digital information sent from the transmission side into N bits, and the information divided into N bits,
And a means for performing correction while referring to the N-bit string and the second N-bit string, and converting the data into "0" or "1".

[0007]

In the present invention, the transmitting side sets "1" to the first N (N
Is an odd number) bit string, “0” is converted to a second N bit string having the longest Hamming distance from the first N bit string, and digital information to be transmitted is transmitted to the first conversion unit and the second The conversion means converts and transmits to the receiving side, the receiving side divides the digital information sent from the transmitting side every N bits, and the information divided into N bits is the first N-bit string and the second N-bit string. While referring to the N bit string of, the correction is performed and converted into “0” or “1”.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An alarm radio interlocking system will be described below as an embodiment of the present invention with reference to the drawings. FIG.
FIG. 3 is a schematic configuration diagram of an alarm wireless interlocking system. This alarm wireless interlocking system includes an alarm 1, a transmitter 3, a microcomputer meter 5, and a receiver 7. The transmitter 3 is connected to the alarm device 1, and the receiver 7 is connected to the microcomputer meter 5. When the alarm device 1 detects a gas leak or the like, it issues an alarm with a buzzer or the like and sends a signal to the transmitter 3. Transmitter 3
Sends an alarm signal to the receiver 7 in a message format as shown in FIG. The microcomputer meter 5 cuts off the gas when receiving the alarm signal.

FIG. 2 is a format diagram of a transmission message. The transmission message 11 has a header 12 and a plurality of user arbitrary data 21 following the header 12. The header 12 has a bit synchronization signal 13, a frame synchronization signal 15, and a calling signal 17 defined by the Radio Law. Bit sync signal 13
Is a signal for synchronizing in bit units. The frame sync signal 15 indicates the beginning of a frame. The call signal 17 is a number that is uniquely attached to the radio to identify its own radio.

FIG. 3 is a format diagram of normal user arbitrary data 21. User arbitrary data 21 includes mark 23, STX 25, meter ID signal 27, CRC2
It has 9, time information 31, and CRC33. Mark 23
Is a signal for synchronizing in wireless communication. STX
25 indicates the beginning of the text. Meter ID signal 27
Indicates the ID number of the microcomputer meter 5. CRC code 2
9. The CRC code 33 is a code used for error control. The time information 31 is set to a value in which the time (seconds) before interruption is 0.5 seconds. At the first time when the warning radio wave is emitted, a value of 120 is set by being expressed by a binary number of 8 bits, and the receiver 7 is set to, for example, 40 seconds later.
When it receives a telegram with a value of seconds, it counts the timer in itself, and after 40 seconds, it starts receiving again. At that time, if the time information 31 in which the value of 0 is set can be received, the microcomputer meter 5 is shut off.

FIG. 4 is a format diagram after converting 1 bit of the user arbitrary data 21 by the 3-bit expansion method. The user-specified data 21a after conversion is the mark 2
3a, STX25a, ID27a, and time information 31a. The mark 23a is a signal for synchronizing. S
TX25a indicates the start of text. The meter ID signal 27a indicates the ID number of the microcomputer meter 5. As the time information 31a, a value is set with the time (seconds) until the interruption being 0.5 second as 1. In this embodiment, FIG.
Convert "1" to the first 3-bit string as shown in
Since the triple expansion method of converting "0" into the second 3-bit string is adopted, the STX 25a, ID 27a and time information 31a are data of triple length of the data before conversion. Further, since the receiver 7 performs the error correction based on FIG.
No RC code is added. Note that the CRC code can also be decompressed three times and sent.

FIG. 5 shows conversion of data by the transmitter 3, in which a converted first 3-bit string of "1" and
It is a figure which shows the 2nd converted 3rd bit sequence of "0".
That is, in the transmitter 3, “1” is converted into the first 3-bit string “101”, and “0” is converted into the second 3-bit string “010” having the longest Hamming distance with “101”.

FIG. 6 is an explanatory diagram of error correction by the receiver 7. The receiver 7 divides the transmitted data into 3 bits, and the 3-bit bit string is set to "101" or "0".
It is converted to "1" or "0" with reference to "10".

For example, when "0" is transmitted from the transmitter 3, it is converted into "010" as shown in FIG.
However, an error occurred during transmission and the receiver 7
When "00" is received, the receiver 7 receives the error bit string "0".
00 "is corrected by 1 bit to be a regular bit string" 010 ", and then converted to the final bit value" 0 ".

Similarly, the receiver 7 sets the error bit string "00".
When "1" is received, it is corrected to the regular bit string "101" and then converted to the final bit value "1". The same correction is made thereafter.

When "010" or "101" is sent to the receiver 7 in FIG. 6, no error has occurred and "010" is "0" and "101" is "1". Convert to.

Next, the operation of this embodiment will be described. Here, as a part of the ID 27a and the time information 31a, "1
A case where 4-bit data "001" is transmitted from the transmitter 3 to the receiver 7 will be described. As shown in FIG.
When transmitting 4-bit data 71 "01", 1
The content "1" of the second bit 73 is "101" as the 3-bit string 81 as shown in FIG. 5, and the content "0" of the second bit 75 is "010" as the 3-bit string 83 as shown in FIG. The content "0" of the third bit 77 is shown in FIG.
5, the 3-bit string 85 is converted into "010", and the content "1" of the fourth bit 79 is converted into 3-bit string 87 into "101", as shown in FIG. The data thus converted is transmitted from the transmitter 3 to the receiver 7.

FIG. 8 shows the data received by the receiver 7. The receiver 7 is a 3-bit string 81a, 83a, 85a,
87a is received. In this case, a 1-bit error has occurred in the second 3-bit string 83a and the fourth 3-bit string 87a during transmission between the transmitter 3 and the receiver 7. The received 3-bit string 81a and 3-bit string 85a are regular bit strings, and as shown in FIG. 5, the contents "1" of the first bit 73a and the third bit 77a are unchanged.
Is received as the content "0". 3 bit string received 8
3a (“000”) and 3-bit string 87a (“100”)
Is a wrong bit string, the receiver 7 refers to FIG. 6 and sets "010" as the correct bit string 83b.
Then, "101" as a correct bit string 87b is corrected and converted into the content "0" of the second bit 75a and the content "1" of the fourth bit 79a with reference to FIG.

As described above, according to this embodiment, the ID 27a
Since each bit of the time information 31a is converted into a 3-bit string and transmitted so that an error can be corrected, if a 1-bit error occurs in 3-bit data, the error can be corrected and the message is invalidated. Without increasing the communication success rate.

In this embodiment, "1" and "0".
In the above, the operation in the case of converting into the first and second 3-bit strings has been described, but it may be converted into an odd-bit string such as a 5-bit string or a 7-bit string. That is, "1"
Is converted into a first N-bit string (N is an odd number), and “0” is converted into a second N-bit string having the longest Hamming distance from the first N-bit string and transmitted. In this case, (N-1) / 2-bit error correction can be performed. Further, although the above-mentioned embodiments have been described by taking the alarm wireless interlocking system, the present invention is not limited to the alarm wireless interlocking system, but can be applied to other digital data transmission systems.

[0021]

As described above in detail, the present invention is
When random noise or the like occurs, it is possible to provide a data transmission system with a high communication success rate.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an alarm radio interlocking system according to an embodiment of the present invention.

[Fig. 2] Format of transmitted message

[Fig. 3] Format diagram of normal user arbitrary data 21

FIG. 4 is a format diagram of the user arbitrary data 21 after conversion into a 3-bit string.

FIG. 5 is a diagram showing a converted first 3-bit string and a second 3-bit string of “1” and “0”.

FIG. 6 is an explanatory diagram of an error bit string and a corrected bit string.

FIG. 7 is a diagram showing conversion of transmission data.

FIG. 8 is a diagram showing correction of received data.

[Explanation of Codes] 1 ... Alarm device 3 ... Transmitter 5 ... Microcomputer meter 7 ... Receiver 11 ... Transmission message 12 ... Header 13 ... Bit synchronization signal 15 ...・ Frame synchronization signal 17 ・ ・ ・ Calling signal 21 ・ ・ ・ User arbitrary data 23 ・ ・ ・ Mark 25 ・ ・ ・ STX 27 ・ ・ ・ Meter ID 29 ・ ・ ・ CRC code 31 ・ ・ ・ Time information 33 ・ ・ ・ CRC Sign

Claims (2)

[Claims] 1. A first side for converting a "1" into a first N (N is an odd number) bit string on the transmission side.
Conversion means, second conversion means for converting “0” into a second N-bit string having the longest Hamming distance to the first N-bit string, digital information to be transmitted, And a means for converting the digital information sent from the transmitting side into N-bits, and a section for converting the information into N-bits. Is corrected with reference to the first N-bit string and the second N-bit string,
A data transmission system comprising: a means for converting into "0" or "1". 2. The transmitting side is a wireless transmitter connected to an alarm device, the receiving side is a wireless receiver connected to a microcomputer meter, and the alarm signal is sent from the wireless transmitter to the wireless receiver. The data transmission system according to claim 1, wherein