JP5097513B2 - Communications system - Google Patents

Description

  The present invention relates to a communication system that performs communication by transmitting and receiving signals.

  Conventionally, communication systems that perform communication by transmitting and receiving digital signals have been used. In particular, in a communication system that performs communication using a serial transmission method, a transmission device and a reception device are provided so that the digital signal transmitted by the transmission device can be accurately received by the reception device and the received digital signal can be processed. Synchronization of transmission and reception is established. For example, a start-stop synchronization method is used in which a start bit indicating the start of the character data and a stop bit indicating the end of the character data are added before and after the data of one character. In this start-stop synchronization method, when the receiving apparatus detects a start bit from the received signal, it performs a receiving process on the received data for one character that follows.

  In the start-stop synchronization method described above, if a stop bit cannot be detected due to noise or the like during transmission / reception of data for one character, synchronization for receiving continuous character data cannot be established, and the receiving device However, there was a problem that data could not be received normally. To cope with this problem, a timer with a timer value set for one character length was started in response to reception of a stop bit in the receiving apparatus, and the timer was measured when the next stop bit could not be detected. There has been proposed a data transmission device that activates a timer interrupt after a lapse of time and returns the reception operation to an idle state. (For example, refer to Patent Document 1).

JP-A-8-181721

  However, even in the conventional communication system as described above, continuous bit data is received when the accuracy of the clock in one or both of the transmission device and the reception device is not sufficient for the transmission method and the transmission rate. There was a problem that out-of-synchronization occurred. For example, when the transmission method is an NRZ (Non Return to Zero) method, when bits of the same value are arranged in the original data, a state in which the signal level of the encoded data does not change continues for a long time. In such a case, an error between the transmission timing and the reception timing accumulates due to the circuit configuration of the receiving apparatus, and thus there is a possibility that loss of synchronization occurs.

  In order to make it difficult to cause loss of synchronization even when bits having the same value are arranged in this way, it is conceivable to improve the accuracy of the clock in the transmission device and the reception device. However, in order to improve the clock accuracy, it is necessary to use an oscillation element with a small frequency deviation, for example, a crystal oscillator, which causes an increase in cost.

  The present invention has been made in view of the above, and can provide a communication system that can easily prevent out-of-synchronization and can provide a low-cost device configuration using an oscillation element having a large frequency deviation. The purpose is to provide.

In order to solve the above-described problems and achieve the object, the communication system according to claim 1 is a digital information including a plurality of codes that can take two or more values. , it was converted to the different levels of the signals, a corresponding different level communication system that performs communication using a digital signal including a signal of, to the digital information, to each code of a predetermined number of the predetermined number Delimiter information inserting means for inserting the same delimiter information consisting of a plurality of codes having different values alternately at the end of the code, and the digital information into which the delimiter information is inserted is converted into the digital signal and transmitted. A transmission unit; a reception unit that receives the digital signal transmitted by the transmission unit and converts the digital signal to the digital information; and Recognizes the delimiter information included in the digital information, characterized in that it comprises a processing means for performing predetermined processing on the basis of the recognition result.

Further, in the communication system according to claim 2, in the digital information including a plurality of codes that can take two or more values, the plurality of codes having different values are converted into signals of different levels, respectively. A communication system for performing communication using digital signals including signals of different levels, wherein a plurality of values having different values alternately for each predetermined number of codes at the end of the predetermined number of codes with respect to the digital information Delimiter information inserting means for inserting delimiter information consisting of the codes of the above, a transmitting means for converting the digital information into which the delimiter information has been inserted into the digital signal and transmitting it, and the digital signal transmitted by the transmitting means Receiving means for receiving and converting the digital information, and the delimiter information included in the digital information converted by the receiving means Identifies, and processing means for performing predetermined processing on the basis of the recognition result, the delimiter information insertion means, among the digital information consisting of the code of the predetermined number, the number of symbols is a predetermined value is even or It is characterized by providing the value of the said division | segmentation information so that the even / odd information which shows which is an odd number may be included .

  A communication system according to a third aspect is the communication system according to the first or second aspect, wherein the delimiter information is 2-bit digital information.

  According to the first aspect of the present invention, since the delimiter information composed of a plurality of codes having different values is inserted for every predetermined number of codes of the digital information which is the original data, the digital information of the original data Even if the same value codes are arranged, the values are always different in the portion where the delimiter information is inserted. Therefore, since the signal level of the digital signal after conversion from the digital information in which the delimiter information is inserted always changes at regular intervals, it is possible to reset the accumulation of errors between the transmission timing and the reception timing. And the occurrence of loss of synchronization can be prevented. Thereby, an oscillation element with a large frequency deviation can be used, and cost reduction can be achieved.

According to the second aspect of the present invention, since the delimiter information composed of a plurality of codes having different values is inserted every predetermined number of codes of the digital information that is the original data, Even if the same value code is arranged in the digital information, the value is always different in the portion where the delimiter information is inserted. Therefore, since the signal level of the digital signal after conversion from the digital information in which the delimiter information is inserted is always changed at regular intervals, the accumulation of errors between the transmission timing and the reception timing can be reset. The occurrence of loss of synchronization can be prevented. Thereby, an oscillation element with a large frequency deviation can be used, and cost reduction can be achieved.
Further, since the delimiter information insertion means determines the delimiter information value so as to include even / odd information, it is possible to detect an error occurring in the digital signal during transmission / reception of the digital signal based on the delimiter information.

  According to the third aspect of the present invention, since 2-bit digital information is used as the delimiter information, an increase in the amount of information accompanying insertion of the delimiter information into the digital information of the original data is minimized. be able to.

  Hereinafter, embodiments of a communication system according to the present invention will be described in detail with reference to the accompanying drawings. [I] First, the basic concept common to each embodiment was explained, then [II] specific contents of each embodiment were sequentially explained, and finally [III] a modification to each embodiment. explain. However, the present invention is not limited to each embodiment.

[I] Basic concept common to the embodiments First, the basic concept common to the embodiments will be described. The communication system according to each embodiment aims to convert digital information into a digital signal and perform communication using the digital signal. Here, digital information refers to information composed of a plurality of codes that can take two or more values, and a digital signal refers to signals of different levels associated with each of a plurality of codes having different values. It shall mean the signal that contains. In each of the following embodiments, as an example, description will be made on the assumption that digital information is composed of a plurality of bits having a value of “0” or “1”. Further, the digital signal is converted to the NRZ method in which the signal level is high level when the bit value of the digital information is “1” and the signal level is low level when the bit value is “0”. It is assumed that the digital information is converted based on this.

  The application target of the communication system according to each embodiment is arbitrary. For example, the communication system is applied to a home alarm device for detecting and alarming a fire occurrence or a gas leak in a home, and between a plurality of the home alarm devices. Communication between each other and applied to disaster prevention systems for large-scale buildings such as underground shopping malls and buildings, and between fire alarms, monitoring sensors, etc. Can be made to communicate. Moreover, the mode of communication is also arbitrary, and communication means such as wireless, wired, and optical communication can be used.

  One of the characteristics of the communication system according to each embodiment is that, roughly, delimiter information composed of a plurality of bits having different values is inserted for each predetermined number of bits of digital information that is original data. As a result, even if bits having the same value are arranged in the original data, the values are always different in the portion where the delimiter information is inserted. Therefore, since the signal level of the encoded data is always changed at regular intervals, accumulation of errors between the transmission timing and the reception timing can be reset, and the occurrence of loss of synchronization can be prevented. Accordingly, an oscillation element having a large frequency deviation can be used, and cost reduction can be achieved.

[II] Specific Contents of Each Embodiment Next, specific contents of each embodiment according to the present invention will be described.

[Embodiment 1]
First, the first embodiment will be described. This form is a basic form for inserting delimiter information.

(Configuration of communication system)
First, the configuration of the communication system will be described. FIG. 1 is a functional block diagram showing the electrical configuration of the communication system. As illustrated in FIG. 1, the communication system 1 includes a transmission device 10 and a reception device 11.

(Configuration of Communication System—Transmitting Device 10)
The transmission device 10 is for transmitting a digital signal to the reception device 11, and includes a bit insertion unit 100, a transmission unit 101, and a transmission control unit 102.

  The bit insertion unit 100 is for inserting delimiter data composed of a plurality of bits alternately having different values for each predetermined number of bits into digital information that is original data of a digital signal transmitted from the transmission device 10. This corresponds to the delimiter information insertion means in the claims. Although the specific content of the delimiter data is arbitrary, for example, “10” or “01” can be used as delimiter data as 2-bit digital information having different values alternately.

  The transmission unit 101 converts the digital information in which the delimiter data is inserted by the bit insertion unit 100 into a digital signal according to a predetermined transmission scheme based on control by the transmission control unit 102, and transmits the digital information. Corresponds to the transmission means in FIG.

  The transmission control unit 102 inputs the digital information to be transmitted to the bit insertion unit 100, inserts the delimiter data, inputs the digital information with the delimiter data inserted into the transmission unit 101, and controls the transmission unit 101 Thus, a digital signal is transmitted at a predetermined transmission timing.

  The specific configuration of the transmission device 10 is arbitrary, and a known transmitter can be used. Details of digital signal transmission control performed by the transmission apparatus 10 will be described later.

(Configuration of communication system-receiving device 11)
The reception device 11 is for receiving a digital signal transmitted from the transmission device 10 and includes a reception unit 110, a bit deletion unit 111, and a reception control unit 112.

  The receiving unit 110 receives the digital signal transmitted from the transmitting unit 101 and converts the received digital signal into digital information according to a predetermined transmission method, and corresponds to the receiving unit in the claims. ing.

  The bit deletion unit 111 recognizes the delimiter data included in the digital information decoded by the receiving unit 110 by a predetermined method, and deletes the delimiter data from the digital information. Corresponds to the means.

  The reception control unit 112 controls the reception unit 110 to receive a digital signal at a predetermined reception timing, inputs the digital information converted by the reception unit 110 to the bit deletion unit 111, and deletes the bit. The unit 111 performs predetermined processing based on the digital information from which the delimiter data has been deleted.

  The specific configuration of the receiving device 11 is arbitrary, and a known receiver can be used. Details of the digital signal reception control performed by the reception device 11 will be described later.

(Operation of communication system)
Next, the operation of the communication system 1 according to the first embodiment will be described. FIG. 2 is a flowchart schematically showing an operation flow of the communication system 1, and FIG. 3 is a schematic diagram showing digital information before and after insertion of delimiter data and a digital signal transmitted from the transmission unit 101.

  As shown in FIG. 2, when digital information is input to the transmission control unit 102 by a predetermined input means, the transmission control unit 102 inputs the input digital information to the bit insertion unit 100 (step SA-1). . Here, it is assumed that “1111111111111111” is input to the transmission control unit 102 as digital information.

The bit insertion unit 100 inserts delimiter data into the input digital information every predetermined number of bits (step SA-2). Here, it is assumed that the bit insertion unit 100 inserts “10” as delimiter data every 8 bits. In this case, for example, as shown in FIG. 3, the digital information after inserting the delimiter data is “11111111 10 11111111 10 ” (the underlined portion indicates delimiter data).

  The bit insertion unit 100 inputs the digital information after inserting the delimiter data to the transmission control unit 102. The transmission control unit 102 inputs the input digital information after insertion of the delimiter data to the transmission unit 101 (step SA-3), causes the transmission unit 101 to convert the digital information, and converts the converted digital signal to a predetermined value. Is transmitted to the receiving device 11 at the transmission timing (step SA-4).

  When the reception control unit 112 detects by a predetermined means that the digital signal transmitted from the transmission unit 101 has been received by the reception unit 110 (step SA-5, Yes), the reception control unit 112 causes the digital signal to be transmitted at a predetermined timing. The signal is received, and the received digital signal is converted into digital information by the receiving unit 110 (step SA-6). Here, as shown in FIG. 3, in the digital signal transmitted by the transmission unit 101, the signal level changes at a position corresponding to the delimiter signal. Accordingly, the reception timing at the receiving unit 110 is reset with the change in the signal level, and accumulation of errors between the reception timing and the transmission timing at the transmission unit 101 is eliminated.

  Subsequently, the reception control unit 112 inputs the converted digital information to the bit deletion unit 111 (step SA-7). The bit deleting unit 111 refers to the input digital information, recognizes the delimiter data, and deletes the recognized delimiter data (step SA-8). As a result, the digital information becomes “1111111111111111” which is the same as the digital information initially input to the transmission control unit 102. The reception control unit 112 executes a predetermined process based on the digital information from which the delimiter data has been deleted by the bit deletion unit 111 (step SA-9).

(Effect of Embodiment 1)
As described above, according to the first embodiment, since the delimiter data composed of a plurality of bits having different values alternately is inserted for each predetermined number of bits of the digital information that is the original data, the same value is added to the digital information of the original data. Even if these bits are lined up, the value is always different in the portion where the delimiter data is inserted. Therefore, since the signal level of the digital signal after being converted from the digital information into which the delimiter data is inserted is always changed at regular intervals, the accumulation of errors between the transmission timing and the reception timing can be reset, Occurrence of loss of synchronization can be prevented. Accordingly, an oscillation element having a large frequency deviation can be used, and cost reduction can be achieved.

  In addition, since 2-bit digital information is used as delimiter data, an increase in the amount of information associated with insertion of delimiter data into the digital information of the original data can be suppressed to a minimum.

[Embodiment 2]
Next, a second embodiment will be described. In this form, the value of the delimiter information is determined so as to include even / odd information.

  The configuration of the second embodiment is substantially the same as the configuration of the first embodiment except where otherwise specified, and the same configuration as that of the first embodiment is used in the first embodiment. The same reference numerals and / or names are attached as necessary, and the description thereof is omitted.

(Bit insertion unit 100)
The bit insertion unit 100 according to the second embodiment determines the delimiter data so that the parity bit is included. Here, the parity bit refers to whether the number of bits whose value is “1” (or “0”) is an even number or an odd number in digital information having a predetermined number of bits. Corresponds to even / odd information in the range. The specific content of the parity bit is arbitrary. For example, in 8-bit digital information, “0” is set when the number of bits whose value is “1” is an even number, and “1” when the number is odd. It can be. Alternatively, “1” may be set when the number of bits having a value “1” is an even number, and “0” may be set when the number is an odd number. The parity bit in the former case is called even parity, and the parity bit in the latter case is called odd parity.

  As in the case of the first embodiment described above, when the delimiter information is 2-bit digital information, for example, the upper bits are even parity, and the lower bits are mutually different values from the even parity values ( For example, by using odd parity, it is possible to determine 2-bit delimited data having different values alternately. For example, when the 8-bit digital information to be inserted into the delimiter data is “10010011”, the number of bits having the value “1” is four and an even number, so the even parity is “0” and the delimiter data is “ 01 ".

(Operation of communication system)
Next, the operation of the communication system 1 according to the second embodiment will be described. FIG. 4 is a flowchart schematically showing the operation flow of the communication system 1.

  As shown in FIG. 4, when digital information is input to the transmission control unit 102 by a predetermined input means, the transmission control unit 102 inputs the input digital information to the bit insertion unit 100 (step SB-1). . Here, it is assumed that “0101010000000” is input to the transmission control unit 102 as digital information.

The bit insertion unit 100 inserts delimiter data into the input digital information every predetermined number of bits (step SB-2). Of the digital information, the first half of 8 bits “01010100” includes 3 bits having a value of “1”, so that the even parity is “1”. Therefore, the bit insertion unit 100 inserts “10” as delimiter data for the first 8 bits. On the other hand, in the latter 8 bits “00000000”, since the number of bits having a value “1” is 0, the even parity is “0”. Therefore, the bit insertion unit 100 inserts “01” as the delimiter data for the latter 8 bits. In this case, the digital information after inserting the delimiter data is “01010100 10 00000000 01 ” (the underlined portion indicates the delimiter data).

  Hereinafter, Step SB-3 to Step SB-7 in FIG. 4 are the same as Step SA-3 to Step SA-7 shown in FIG.

  In step SB-7, the bit deletion unit 111 to which the digital information converted by the reception control unit 112 is input refers to the input digital information and recognizes the delimiter data. At this time, the even parity which is the upper value in the 2-bit delimiter data is referred to (step SB-8). Further, the bit deletion unit 111 calculates even parity based on the 8-bit digital information in which the delimiter data has been inserted (step SB-9). Then, the even parity referenced in step SB-8 is compared with the even parity calculated in step SB-9 (step SB-10). If the comparison results match (step SB-10, Yes), the bit deletion unit 111 deletes the delimiter data, and the reception control unit 112 deletes the delimiter data by the bit deletion unit 111. Based on the above, predetermined processing is executed (step SB-11). On the other hand, when the comparison results are different (step SB-10, No), the bit deletion unit 111 determines that the signal content has changed during communication of the digital signal, and the reception control unit 112 Information indicating an error is output (step SB-12). The reception control unit 112 executes a predetermined process based on the error information (step SB-13).

(Effect of Embodiment 2)
As described above, according to the second embodiment, since the bit insertion unit 100 determines the delimiter data so as to include the parity bits, in addition to the basic effect in the first embodiment described above, Based on this, it is possible to detect errors that occur during transmission and reception of digital signals.

[III] Modifications to Each Embodiment While each embodiment according to the present invention has been described above, the specific configuration and means of the present invention are the same as the technical idea of each invention described in the claims. Modifications and improvements can be arbitrarily made within the range. Hereinafter, such a modification will be described.

(About problems to be solved and effects of the invention)
First, the problems to be solved by the invention and the effects of the invention are not limited to the above-described contents, and the present invention solves the problems not described above or has the effects not described above. There are also cases where only some of the described problems are solved or only some of the described effects are achieved.

  The communication system according to the present invention can be applied to a communication system that performs communication by transmitting and receiving signals, can easily prevent the occurrence of loss of synchronization, and has a low-cost apparatus configuration using an oscillation element having a large frequency deviation. It is useful for communication systems that can.

1 is a block diagram conceptually showing the electrical configuration of a communication system. 3 is a flowchart schematically showing an operation flow of the communication system 1. It is the schematic which showed the digital information before and after the delimiter data insertion, and the digital signal transmitted from the transmission part. 3 is a flowchart schematically showing an operation flow of the communication system 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Communication system 10 Transmission apparatus 11 Reception apparatus 100 Bit insertion part 101 Transmission part 102 Transmission control part 110 Reception part 111 Bit deletion part 112 Reception control part

Claims (3)

In digital information consisting of a plurality of codes that can take two or more values, the plurality of codes having different values are converted into signals of different levels, and communication is performed using digital signals including the signals of the different levels. A communication system for performing
Delimiter information inserting means for inserting the same delimiter information consisting of a plurality of codes having different values alternately at the end of the predetermined number of codes for the predetermined number of codes ,
Transmitting means for converting the digital information into which the delimiter information has been inserted into the digital signal and transmitting the digital information;
Receiving means for receiving the digital signal transmitted by the transmitting means and converting it into the digital information;
Processing means for recognizing the delimiter information included in the digital information converted by the receiving means and performing a predetermined process based on the recognition result;
A communication system comprising: In digital information consisting of a plurality of codes that can take two or more values, the plurality of codes having different values are converted into signals of different levels, and communication is performed using digital signals including the signals of the different levels. A communication system for performing
Delimiter information insertion means for inserting delimiter information consisting of a plurality of codes having different values alternately at the end of the predetermined number of codes for the predetermined number of codes,
Transmitting means for converting the digital information into which the delimiter information has been inserted into the digital signal and transmitting the digital information;
Receiving means for receiving the digital signal transmitted by the transmitting means and converting it into the digital information;
Processing means for recognizing the delimiter information included in the digital information converted by the receiving means and performing a predetermined process based on the recognition result;
The delimiter information insertion means includes the even-odd information indicating whether the number of codes having a predetermined value is an even number or an odd number among the digital information including the predetermined number of codes. Determining the value,
A communication system comprising: The delimiter information is 2-bit digital information;
The communication system according to claim 1 or 2.

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