JP6916840B2 - Information communication system and information communication device - Google Patents

Description

The present invention relates to an information communication system and an information communication device that include a plurality of information communication devices and synchronizes the information communication devices by communication.

As a general time synchronization method between a plurality of information communication devices, for example, the IEEE1588 Precision Time Protocol (PTP) of Non-Patent Document 1 is known. Non-Patent Document 1 defines a master device having a reference time and a slave device that synchronizes the time with the time of the master device, and by periodically exchanging time synchronization packets between the master device and the slave device. Correct the time of the slave device.

Specifically, the time of the master device and the reception time of the slave device of the packet transmitted from the master device to the slave device, and the transmission time of the slave device and the reception time of the master device of the packet transmitted from the slave device to the master device. Is used to estimate and correct the time offset, which is the time difference between the master device and the slave device, in the slave device.

"IEEE Standard for a Precision Clock Synchronization Protocol for Networked Mechanism and Control Systems." IEEE Standard 1588-2008.

However, in IEEE 1588 (PTP), high-precision synchronization may not be possible due to the frequency deviation between the clocks of the master device and the slave device. That is, each of the master device and the slave device independently has a clock that is a source of operation of the device. Even if the nominal frequency of each clock is the same, since the clock of the master device and the clock of the slave device have individual differences, the frequencies are actually different, and there may be a frequency deviation between the clocks. Therefore, the time flow differs between the master device and the slave device because the time ticks are different.

In the above IEEE1588 PTP system, the slave device tries to synchronize the time using the time of the master device transmitted from the master device as it is, even though the time flow is slightly different in each device. The synchronization timing of the device and the slave device was out of sync, and high-precision synchronization could not be performed.

The present invention has been made to solve the above problems, and an object of the present invention is to provide an information communication system and an information communication device capable of synchronizing a master device and a slave device with high accuracy.

The information communication system of the present invention is an information communication system in which the slave device synchronizes with the master device by information communication, and the master device and the slave device receive information with a transmitter for transmitting information. The slave device includes the master device and the clock, which oscillates at a predetermined frequency and gives an operation timing of each part in the device, and a clock that ticks from the clock as a source vibration. A propagation time calculation unit that calculates the propagation time of information transmitted to and from the slave device, a time difference calculation unit that calculates the time difference between the master device and the slave device based on the propagation time, and the time difference. The master device transmits information to the slave device, the slave device receives the information, and the slave device sends other information to the master device. Submit and receives the specific information is the master device, the transmission of the information in the master device and receives distance Delta] t m to the reception of the specific _information, from the reception of the information in the slave device of the further receiving and transmitting interval Delta] t s to the transmission of _information, the frequency f _m of the clock of the master _device, the frequency of the clock of the slave device and f _s, the horizontal axis indicates the frequency, the two-dimensional plane and the vertical axis represents the time vector a, vector _{B (f s, Δt s)} T in, _{(f m,} Δt _m) when is ^T, the propagation time calculation unit, the said vector a spanned over the two-dimensional plane vector B The propagation time is calculated by dividing the area of the wave number region of the triangle formed by the above by the frequency of the clock of the master device.

The information communication device of the present invention is an information communication device that synchronizes with other information communication devices by information communication, and oscillates at a predetermined frequency with a transmitter for transmitting information and a receiver for receiving information. Propagation time calculation that has a clock that gives the operation timing of each part in the device and a clock that ticks from the clock as a source, and calculates the propagation time of information transmitted to and from the other information communication device. A time difference calculation unit that calculates the time difference between the unit and the other information and communication device based on the propagation time, and a synchronization control unit that controls synchronization with the other information and communication device based on the time difference. And, the information transmitted from the other information communication device is received, another information is transmitted to the other information communication device, and the other information is transmitted from the transmission of the information in the other information communication device. the reception interval Delta] t m up to the _reception, the information reception and transmission interval Delta] t s from the reception of the information in the communication apparatus until the transmission of the further _information, the frequency of the clock of another information communication apparatus f _m, the the frequency of the clock information communication apparatus as _{f s,} the horizontal axis indicates the frequency, the vector and the vertical axis in the two-dimensional plane is a time a, the vector _{B (f s, Δt s)} T, (f m, Δt m) T Then, the propagation time calculation unit divides the area of the wave number region of the triangle formed by the vector A and the vector B stretched on the two-dimensional plane by the frequency of the clock of the other information communication device. This is characterized in that the propagation time is calculated.

According to the present invention, it is possible to obtain an information communication system and an information communication device capable of synchronizing a master device and a slave device with high accuracy.

It is a schematic diagram of the information communication system which concerns on embodiment. It is a functional block diagram of the information communication apparatus which constitutes the information communication system which concerns on embodiment. It is a functional block diagram of the control part which concerns on embodiment. It is a figure which shows the mode of communication for counting the number of pulses of a clock. It is a figure which shows the mode of communication for synchronization of the information communication system which concerns on embodiment. It is the figure which represented the transmission / reception interval of a master device and the transmission / reception interval of a slave device on a two-dimensional plane in which the horizontal axis represents frequency and the vertical axis represents time. It is a figure which shows the mode of another communication for synchronization of the information communication system which concerns on embodiment. Reception interval Delta] t _m of the master device, the reception and transmission interval Delta] t _s of the slave device, the observation time vector ^{_{(f, Δt m) T,}} (f, Δt s) as ^T, a diagram representing the frequency-time plane. It is a figure for demonstrating the case where the clock domain is different. It is a figure for _{demonstrating the} propagation time t _ds , time difference t 0 s. It is a figure for _{demonstrating the} propagation time t _dm and time difference t 0 m. This is an example of an operation flowchart of the information communication system according to the embodiment.

Hereinafter, the information communication system and the information communication device according to the embodiment will be described with reference to FIGS. 1 to 12.

[1. Embodiment]
[1-1. Constitution]
FIG. 1 is a schematic diagram of an information communication system according to an embodiment. FIG. 2 is a functional block diagram of an information communication device constituting the information communication system according to the embodiment.

The information communication system 100 according to the present embodiment is composed of a plurality of information communication devices 1, and each device 1 synchronizes by information communication. The information communication device 1 serving as the slave device synchronizes with the information communication device 1 serving as the master device. The master device is an information communication device 1 to be synchronized with another information communication device 1 in the information communication system 100. The slave device is an information communication device 1 that synchronizes with another information communication device 1 that is a master device in the information communication system 100. The slave device synchronizes with the master device through transmission / reception of synchronization information for synchronizing from the master device to the slave device.

In the following, the information communication device 1 serving as the master device will be referred to as the master device 1a, and the information communication device 1 serving as the slave device will be referred to as the slave device 1b.

The master device 1a and the slave device 1b communicate information by wire or wirelessly. As wireless communication, wireless LAN and Bluetooth (registered trademark) can be used. Here, an example in which the information communication device 1 synchronizes by transmitting and receiving information wirelessly will be described.

(Information and communication equipment)
The information communication device 1 includes a computer, stores a program in an HDD, an SSD, or the like, and processes the information and communication device 1 by a CPU to perform necessary calculations in a control unit described later.

Specifically, the information communication device 1 includes a communication unit 10, a clock 20, a clock 30, a counter 40, a storage unit 50, an external interface 60, and a control unit 70. For example, each part 10 to 70 is configured as hardware. The control unit 70 may be configured as software. It is possible to appropriately change the design of which part of the control unit 70 is configured as software.

The communication unit 10 transmits / receives information to / from another information / communication device 1. The communication unit 10 includes a transmitter 11, a receiver 12, a transmission timing detection unit 13, and a reception timing detection unit 14.

The transmitter 11 is a device that transmits the input information. Specifically, the transmitter 11 decomposes the information into the minimum components in time series and transmits the information to the outside. The packet length (communication information amount) of information is arbitrary and may be different for each communication.

The receiver 12 is a device that receives information from the outside. Specifically, the receiver 12 reconstructs the information received from the outside of the device 1 and decomposed into the minimum components in time series, and outputs the information to other configurations in the device 1.

As shown in FIG. 2, antennas may be provided in the transmitter 11 and the receiver 12, respectively, or a changeover switch may be provided to share one antenna. The transmitter 11 and the receiver 12 may not operate the other while one of them is operating, or both may be operated at the same time.

The transmission timing detection unit 13 detects the transmission timing of the predetermined information element position of the information transmitted by the transmitter 11. This transmission timing is detected based on the clock period of the clock 20 described later (in other words, the period of the oscillating pulse of the clock 20). That is, the transmission timing is expressed based on an integral multiple of the clock period.

Further, the transmission timing detection unit 13 outputs the detection result to another configuration in the device 1. The information referred to here is, for example, a packet, and in this case, the predetermined information element position is a bit position. For example, when the information is decomposed into eight minimum components in time series, the transmission timing detection unit 13 detects the timing at which the third information element position (bit position) is transmitted, and detects the third information element. The timing at which the position (bit position) is transmitted is output to the outside.

The reception timing detection unit 14 detects the reception timing of the predetermined information element position of the information received by the receiver 12. This reception timing is detected based on the clock period of the clock 20 described later (in other words, the period of the oscillating pulse of the clock 20). That is, the reception timing is expressed as an integral multiple of the clock period.

Further, the reception timing detection unit 14 outputs the detection result to another configuration in the device 1. For example, when the information is decomposed into eight minimum components in time series, the reception timing detection unit 14 detects the timing at which the third information element position (bit position) is received, and detects the third information element. The timing at which the position (bit position) is received is output to the outside.

In the above examples of transmission timing and reception timing, the positions of the same minimum components are both detected, but for example, the transmission timing detection unit 13 of the information communication device 1 serving as the transmitter is the fifth element. The reception timing detection unit 14 of the information communication device 1 serving as the receiver detects the eighth element, and has a predetermined relationship (for example, intervals (here, three)) in each timing detection between the transmission / reception devices 1. It is not always necessary to detect the same position as long as the above is maintained.

The clock 20 oscillates a predetermined frequency and outputs a signal for giving an operation timing of each part of the device 1. As a result, each part in the device 1 operates in synchronization with the clock 20. The clock 20 has an inherent finite oscillation frequency tolerance. That is, the clock 20 has an error (for example, 20 ppm) with respect to a predetermined oscillation frequency (for example, 10 MHz). As the clock 20, for example, an oscillator having a fixed frequency such as a crystal oscillator can be used.

Even if the clock 20 has the same nominal frequency between the master device 1a and the slave device 1b, there are actually individual differences. That is, there is a frequency deviation between the frequencies of the clock 20 of the master device 1a and the slave device 1b.

The clock 30 ticks the output signal of the clock 20 as a source vibration and outputs a relative time. The relative time output of the clock 30 is performed, for example, in response to an external request.

The counter 40 counts the number of pulses oscillated by the clock 20 (hereinafter, referred to as the number of pulses).

The storage unit 50 is a recording medium such as an HDD, SSD, memory, or register. The storage unit 50 stores or stores information necessary for the control unit 70 to perform an operation. The time of the clock 30 corresponding to the transmission timing or the reception timing described later may be held in a recording medium that can be held only by accessing the hardware without using the CPU or software. This is because jitter caused by software can be eliminated. It is important not to receive software jitter in associating the transmission / reception timing with the time, and after the transmission / reception timing and the time are associated with each other, the transmission / reception timing and the time may be stored in a low-speed access area. Here, the memory as the storage unit 50 inputs and outputs arbitrary information and stores the information in the designated storage area. Information is stored by a storage request from the outside, and the information to be stored and the storage area are input at that time. The information is referenced by a reference request from the outside, and at that time, the storage area of the reference information is input, and the information of the storage area specified by the input is output. The storage of information may be retained only during the operation of the present device or may be permanent including when the operation is stopped.

The external interface 60 (hereinafter, also referred to as an external I / F60) connects the inside and the outside of the apparatus 1 and inputs / outputs arbitrary information. The information includes, for example, transmission / reception data and the time of the clock 30. The external I / F 60 acquires, for example, information to be stored in the storage unit 50 from the outside. Further, the external I / F 60 may acquire the time from the reception timing detected by the reception timing detection unit 14 to the transmission timing detected by the transmission timing detection unit 13 from the outside, and use the time in the scheduler 75 described later. ..

FIG. 3 is a functional block diagram of the control unit 70. The control unit 70 controls the overall operation of each unit of the present device 1. The control unit 70 has a configuration different from the configuration common to the master device 1a and the slave device 1b. The master device 1a does not need a configuration peculiar to the slave device 1b, and the slave device 1b does not need a configuration peculiar to the master device 1a. However, one information communication device 1 may have both a function as a master device 1a and a function as a slave device 1b. For example, the position as the master device 1a and the position as the slave device 1b may be reversed between the two information communication devices 1. Further, one information communication device 1 may function as a master device 1a in relation to another information communication device 1, and may function as a slave device 1b in relation to another information communication device 1 (master device 1a). ..

(Control unit of master device)
The control unit 70 of the master device 1a includes a main control unit 71, transmission / reception data I / F 72, communication control unit 73, time recording unit 74, scheduler 75, counter control unit 76, and count transmission control unit 77.

The main control unit 71 is linked with each unit in the control unit 70, and controls the operation of each unit in the control unit 70. The transmission / reception data I / F72 is in a format in which the information of the storage unit 50 and the external I / F70 can be transmitted / received to the outside of the device 1. Further, the transmission / reception data I / F 72 formats the information received from the outside of the device 1 into a format suitable for the control unit 70 and the storage unit 50.

The communication control unit 73 controls the operation of the communication unit 10. The communication control unit 73 inputs / outputs transmission / reception information between the communication unit 10 and the control unit 70.

The time recording unit 74 stores the transmission timing of the predetermined information element position of the information transmitted by the transmission timing detection unit 13 in the memory in association with the time of the clock 30 at the transmission timing. In this association, for example, the time recording unit 74 receives a signal from the transmission timing detection unit 13 that the transmission timing of the predetermined information element position of the transmitted information is detected, and refers to the time of the clock 30. , Correspond the time with the transmission timing.

Further, the time recording unit 74 is also a time addition unit that puts the time corresponding to the transmission timing on the information to be transmitted. Similar to the transmission, the time recording unit 74 stores the reception timing of the predetermined element position of the information received by the reception timing detection unit 14 in the memory in association with the time of the clock 30 at the reception timing. Further, the time recording unit 74 puts the time corresponding to the reception timing on the information and causes the transmitter 11 to transmit the time.

As described above, in the present embodiment, the "time" refers to the time of the clock 30 corresponding to the detected transmission timing or reception timing of the predetermined information element position of the information, and the "time" refers to the difference between the times. ..

The scheduler 75 causes the transmitter 11 to transmit information on a preset schedule. For example, the scheduler 75 causes the transmitter 11 to transmit synchronization information at regular intervals. The fixed interval is, for example, 1 second. The scheduler 75 manages a schedule from receiving information to transmitting it. That is, the scheduler 75 transmits information at preset transmission / reception intervals. The scheduler 75 may change the information transmission interval or the information transmission / reception interval via the external I / F60.

The counter control unit 76 causes the counter 40 to count the number of pulses of the clock 20. Specifically, as shown in FIG. 4, the master device 1a transmits synchronization information to the slave device 1b at least twice at _{a transmission interval ΔT m.} At that time, the counter 40 is controlled by the counter control unit 76 to count the number of pulses of the clock 20 _{at the transmission interval ΔT m of the synchronization information from the master device 1a to the slave device 1b.} The transmission interval ΔT _m is, for example, 1 second.

The count number transmission control unit 77 causes the transmitter 11 to transmit the number of pulses counted by the counter 40 and the counter control unit 76 to the slave device 1b. The count number transmission control unit 77, for example, puts the number of pulses on the information and causes the transmitter 11 to transmit the information.

(Control unit of slave device)
The control unit 70 of the slave device 1b includes a main control unit 71, transmission / reception data I / F 72, communication control unit 73, time recording unit 74, scheduler 75, synchronization request unit 80, counter control unit 81, frequency acquisition unit 82, transmission / reception interval. It has a calculation unit 83, a transmission / reception interval calculation unit 84, an area calculation unit 85, a propagation time calculation unit 86, a time difference calculation unit 87, and a synchronization control unit 88. Since each part 71 to 75 is the same as each part 71 to 75 of the master device 1a, the description thereof will be omitted.

The synchronization request unit 80 causes the transmitter 11 to transmit a signal requesting information for synchronization with the master device 1a. The information for synchronizing to the master device 1a, the number of pulses in the transmission interval [Delta] T _m, the transmission time of the synchronization information of the master device 1a for calculating the reception interval [Delta] T _m, a master for calculating the reception and transmission interval Delta] t _s It is the reception time of another synchronization information of the device 1a.

The counter control unit 81 causes the counter 40 to count the number of pulses of the clock 20. Specifically, the counter 40 is controlled by the counter control unit 81 counts the number of pulses of the clock 20 in the receiving interval [Delta] T _s of the synchronization information transmitted from the master device 1a to the slave device 1b. The reception interval ΔT _s is a time interval corresponding to the transmission interval ΔT _m.

The frequency acquisition unit 82 acquires _{frequencies f m} and f _s from the number of pulses of the clock 20 at the _{transmission interval ΔT m} and the number of pulses of the clock 20 at the reception interval ΔT _s . The number of pulses of the transmission interval [Delta] T _m at clock 20, when the number of pulses of the master device 1a of the clock 20 in one second at the master device 1a, the number of the pulses intended that the clock frequency f _m of the clock 20 of the master device 1a be. The reception interval [Delta] T _s is because the time interval corresponding to the transmission interval [Delta] T _m, the pulse number of the clock 20 in the reception interval [Delta] T _S are those that clock frequency f _s of a clock 20 of the slave device 1b.

The frequency acquisition unit 82 may _{convert the transmission interval ΔT m} into the number of pulses per second even if the transmission interval ΔT m is other than 1 second. For example, if the transmission interval [Delta] T _m is 10m seconds, is the frequency _{f m} which the number of pulses was 100 times that of the master device 1a of clock 20, frequency multiplied by 100. The number of pulses of the clock 20 of the slave device 1b f _s .

FIG. 5 is a diagram showing a mode of communication for synchronizing the information communication system according to the embodiment. _{The transmission / reception interval calculation unit 83 calculates the transmission / reception interval Δt m} from the transmission of the synchronization information to the slave device 1b by the master device 1a to the reception of the synchronization information transmitted from the slave device 1b. Specifically, the transmission / reception interval calculation unit 83 calculates the difference between the reception time of the synchronization information received from the slave device 1b and the transmission time of the synchronization information transmitted by the master device 1a to the slave device 1b. The transmission time and the reception time are times listed in the information transmitted from the master device 1a. The transmission time is added to the information by the time recording unit 75 that functions as the time adding unit of the master device 1a.

As shown in FIG. 5, reception and transmission interval computing unit 84 receives the synchronization information from the master device 1a, calculates the reception and transmission interval Delta] t _s until transmits the synchronization information to the master device 1a. Specifically, receiving and transmitting interval calculating unit 84 obtains the transmission time of the synchronization information to the master device 1a, the reception and transmission interval Delta] t _s by the difference between the reception time of the synchronization information from the master device 1a. The reception / transmission interval calculation unit 80 acquires the transmission time and the reception time from the storage unit 50 or the time recording unit 74.

FIG. 6 is a diagram showing the transmission / reception interval of the master device 1a and the transmission / reception interval of the slave device 1b on a two-dimensional plane in which the horizontal axis is frequency and the vertical axis is time. As shown in FIG. 6, the area calculation unit 85, the vector _{A (= (f s, Δt} s) T) where the horizontal axis is frequency and the vertical axis is stretched on the two-dimensional plane is a time vector B (= ( The area a of the wave number region S of the triangle formed by f _m , ΔT _m ) ^{T) is calculated.} f _m is the clock frequency of the clock 20 of the master device 1a, and f _s is the clock frequency of the clock 20 of the slave device 1b.

Area calculation unit 85, acquires reception interval Delta] t _m obtained by the transmitting and receiving intervals calculation unit 83, receiving and transmitting reception and transmission interval Delta] t _s obtained by the distance calculation unit 84, a frequency _f m was obtained by the frequency acquisition unit 82, a _{f s} Then, the area a is calculated. In the present embodiment, the area calculation unit 85 calculates the area a of the wave number region by dividing the size of the outer product of the vector A and the vector B by 2.

The propagation time calculation unit 86 calculates the propagation time of the information transmitted between the master device 1a and the slave device 1b. In the present embodiment, the propagation time calculation unit 86 calculates the propagation time divided by the frequency f _m of the area a wavenumber region of a triangle formed by the vectors A and B, the master device 1a of the clock 20. At that time, the propagation time calculation unit 86 obtains the area a, the frequency f _m from the area calculation unit 85.

The time difference calculation unit 87 calculates the time difference between the master device 1a and the slave device 1b based on the propagation time obtained by the propagation time calculation unit 86. Specifically, the time difference calculating portion 87 calculates the time difference by adding a propagation time between reception and transmission interval Delta] t _s. As shown in FIG. 5, the time difference here is the interval from the transmission timing of the master device 1a to the transmission timing of the slave device 1b.

The synchronization control unit 88 performs synchronous control based on the time difference obtained by the time difference calculation unit 87. Specifically, the synchronization control unit 88 corrects the ticking value of the clock 30 of the slave device 1b based on the time difference. For example, the synchronization control unit 88 may control the clock 30 itself to correct the time. Alternatively, the synchronization control unit 88 may control the clock 30 so that when the clock 30 outputs the time, the time difference is corrected to output the time. In this way, the synchronization control unit 88 corrects the time of the clock 30 or the time output by the clock 30 based on the time difference, and the time difference is defined by the difference in transmission timing between the master device 1a and the slave device 1b. , Time difference control is synonymous with transmission timing control.

[1-2. Action]
The operation of the information communication system 100 having the above configuration will be described with reference to FIGS. 4 to 11.

[1-2-1. Formulation of propagation time and time difference]
As shown in FIG. 5, the master device 1a transmits information to the slave device 1b, the slave device 1b receives the information after a propagation time, and after the reception, another information is transmitted to the master device 1a. Considering the situation where the master device 1a receives the information after the same propagation time, the propagation time and the time difference are formulated. The information transmitted by the master device 1a and another information transmitted by the slave device 1b are for the purpose of timing for synchronization, and the information includes the information of the master device 1a. The transmission time of the information may be included, but the content of the information and the other information is arbitrary.

(1) In the case of a single clock domain First, when the information communication system 100 has a single clock domain, that is, the clock frequency of the clock 20 of the master device 1a and the clock frequency of the clock 20 of the slave device 1b are the same. In the case of the frequency f, the time observed by each of the devices 1a and 1b and the calculated time can be used as they are in the other devices 1a and 1b.

As shown in FIG. 5, a propagation time t _d to the slave device 1b from the master device 1a, when the propagation time t _d from the slave device 1b to the master device 1a are the same, the propagation time t _d has the formula It can be obtained as in (1).
t _d = (Δt _{m − Δt s} ) / 2… (1)

Further, as described above, the time difference t ₀ between the clocks 20 is the interval from the transmission timing of the master device 1a to the transmission timing of the slave device 1b. For this time difference t ₀ , the equation (2) is established from FIG.
t ₀ = Δt _m −t _d = Δt _s + t _d … (2)

Therefore, the time difference t ₀ between the clocks 20 can be obtained according to the equation (3) using the equation (1).
t ₀ = (Δt _m + Δt _s ) / 2 ... (3)

As shown in FIG. 7, without the slave device 1b is waiting for the information received from the master device 1a, when transmitting other information to the master device 1a, spacing Delta] t _s to transmission from reception in the slave device 1b Although it is a negative number, the equations (1) and (3) are established as in the case where the slave device 1b waits for the information reception from the master device 1a and transmits another information to the master device 1a.

Here, the time observed based on the clock 20 of the clock frequency f has a two-dimensional plane (hereinafter, both frequency and time plane) in the observed time corresponding to the clock frequency on the horizontal axis and the physical timing on the vertical axis. It can be expressed as the above vector. This vector is called an observation time vector. The observation time vector can be expressed as, for example, (f, Δt) ^T. The symbol ^T represents the transpose of the vector. 8, transmission and reception interval [Delta] T _m of the master device 1a, the reception and transmission interval Delta] t _s of the slave device 1b, the observation time vector ^{_{(f, Δt m) T,}} (f, Δt s) as ^T, on the frequency-time plane It is a representation figure.

Here, we focus on the triangular region S spanned by these two observation vectors. Assuming that the base of the triangle of the region S is a side that rides on a straight line representing the frequency f, the length of the base (Δt _{m − Δt s ) is 2 t d} from the equation (1) or the equation (2). Therefore, the area a of the region S can be expressed as in the equation (4).
a = f × (Δt _{m − Δt s} ) / 2 = f × t _d … (4)

Therefore, the propagation time t _d can be expressed by the equation (5) from the equation (4).
t _d = a / f ... (5)

Since the product of frequency and time represents the wave number, the region S can be referred to as the wave number region, and the area a can be referred to as the frequency / time product.

Further, since the midpoint of the base of the wave frequency domain S is Δt _s + (Δt _{m − Δt s} ) / 2 = (Δt _m + Δt _s ) / 2, the clock 20 is according to the equation (2) or (3). The time difference between them is _{t 0 itself.} Further, since the length of the base of the wave number region S is 2 t _d , the time difference t ₀ can be expressed as in the equation (6).
t ₀ = Δt _s + t _d = Δt _m −t _d … (6)

_{In this way, the propagation time t d} and the time difference t ₀ can be obtained by a geometric method using the wave number region S on the frequency / time plane.

(2) In the case of a plurality of clock domains When there are a plurality of clock domains in the information communication system 100, that is, the clock frequency f _{m of the clock 20 of the master device 1a and the clock frequency f s} of the clock 20 of the slave device 1b are different. In this case, the time in one device 1a and 1b cannot be used as it is for the calculation in the other device 1b and 1a.

For example, as shown in FIG. 9, since the frequency and time are linear, the observation time between clock domains can be linearly associated with each other by using a two-dimensional vector on the frequency / time plane. That is, the vector observation time ta _m at frequency _{f m (f m, ta m} ) if represented by ^T, the observation time ta _s at a frequency _{f s} which corresponds to ta _{m is,} (f _{m, ta} ^m) in ^T _(f s, _ta ^s) of a vector that is on the extension can be obtained as ta _s is an element of ^T. Similarly, if the observation time tb _m at frequency _{f m} vector _(f m, _tb ^m) and expressed by ^T, the observation time tb _s at a frequency _{f s} which corresponds to _{tb m, (f m, tb} m) T _(f s, _tb ^s) of a vector that is on the extension of the at can be obtained as tb _s is an element of ^T.

Therefore, the physical timing interval corresponding to the interval (tb _{m −} ta _{m ) observed at the frequency f m} is observed as the interval (tb _{s −} ta _s ) _{at the frequency f s.} In other words, a physically common time interval, by having different frequencies, as shown in FIG. 9, the observed interval master device 1a (tb m _{-ta m),} observed interval slave device 1b ( Since _{it is different from tb s} −ta _s ), the time in one device 1a and 1b cannot be used as it is for the calculation in the other device 1b and 1a. Therefore, it is necessary to remove the influence of either the frequency f _m or f _s.

Here, from the equation (5), the propagation time can be obtained by dividing the area a of the wave number region S by the frequency. By dividing the area a of the wave frequency domain S by the other clock domain (frequency), that is, the clock domain (frequency) from which the influence is desired to be removed, the desired clock domain (frequency) can be calculated so that the calculation can be performed only on the desired clock domain (frequency). The propagation time and time difference in the clock domain can be obtained. The area a includes the time on the desired clock domain and the time on the clock domain to be removed, and the desired clock domain is obtained by dividing the area a by the frequency of the clock domain to which the influence is to be removed. This is because only the influence of is left.

Specifically, the propagation time _{t ds} on clock domain _{f s,} if you want to find the time difference _{t 0 s,} as shown in FIG. 10, the observation time vector _{(f m,} Δt _m) wavenumber region S was bottom of ^T is apex of the formed triangle _{(f s,} Δt _s), and by moving in parallel with the base, while maintaining the frequency-time product, converted on the clock domain _{f m} point _{(f m,} Delta] t _sm) to .. This conversion is the vertex (f _s, Δt _s) since the only movement parallel to the base, the height is maintained, and so the area conversion to keep the area of the wave number region S constant. Thus, one side of the triangle wave number region S after the conversion, ride on the clock domain f _m. Assuming that one side is the base of the triangle, the length of this base is equal to twice the propagation time t _{ds observed on the clock domain f s.} In other words, the area of the triangle in the wavenumber domain S after conversion is a, so if the length of the base is x, the equation (7) holds.
_{a = (1/2) × f m} × x ... (7)

From equation (7), equation (8) holds.
x = 2 × (a / f _m )… (8)

The a / f _m of the equation (8) is the propagation time as in the equation (5). Here, the a / f _m is the area a wavenumber region S, the desired clock domain f not _s clock domain f _m, in other words, since it is divided by the clock domain f _m of the person who wants to remove the effects , The propagation time is the propagation time t _{ds on the clock domain f s} .

Therefore, the propagation time t _ds can be obtained by the equation (9).
t _ds = a / f _m ... (9)

In fact, the base of the triangle wave number region S after conversion, the length of time that has moved in parallel on the clock domain f _s along a vector B, since it is 2t _ds, is x = 2t _ds. That is, the time Delta] t _ms observed on clock domain _{f s} which corresponds to the clock domain _{f m} on the observed time Delta] t _m, at 10, the observation time vector ^{_{(f s, Δt ms) T}} ( hereinafter, the vector It is also represented by _{B s).} The base y on the _{clock domain f s of the} triangle spanned by the vector A and the vector B _s (the triangle connected by the points O, P _s , and Q in _{FIG. 10) is 2 t ds} in the same manner as in FIG. .. This base y is equal to the base x because the _{line segment PP s} and the line segment QQ _{m in FIG. 10 are parallel to each other.} Therefore, it can be seen that the base x = 2t _ds.

Further, the time difference t _0s on the clock domain f _s can be obtained by the equation (10) because it is the midpoint of the base y when considered in the same manner as in FIG.
t _0s = Δt _s + t _ds … (10)

Incidentally, the propagation time on the clock domain _{f m t dm,} if you want to find the time difference _{t 0 m,} as shown in FIG. 11, the observation time vector _{(f s,} Δt _s) wavenumber region S was base ^T-form apex of the triangle _{(f m,} Δt _m) and by moving parallel to the base, while maintaining the frequency-time product, converting the clock domain _{f s} on the point _{(f s,} Delta] t _ms) to. This conversion is the vertex (f _m, Δt _m) since the only movement parallel to the base, the height is maintained, and so the area conversion to keep the area of the wave number region S constant. Thus, one side of the triangle wave number region S after the conversion, ride on the clock domain f _s. When the side and bottom side of the triangle, the length of the base is equal to twice the propagation time t _dm observed on clock domain f _m. In other words, since the area of the triangle in the wavenumber domain S after conversion is a, the equation (11) holds, where x is the length of the base.
a = (1/2) × f _s × x… (11)

From equation (11), equation (12) holds.
x = 2 × (a / f _s )… (12)

The a / f _s of the equation (12) is the propagation time as in the equation (5). Here, the a / f _s is the area a wavenumber region S, the desired clock f _m is not a clock domain f _s, that is, because it is divided by the impact at the clock domain f _s of those who want to remove, propagation time is the propagation time _{t dm} on the clock domain _{f m.}

Therefore, the propagation time t _dm can be obtained by the equation (13).
t _dm = a / f _s ... (13)

In fact, the base of the triangle wave number region S after conversion, the length of time that has moved in parallel on the clock domain f _m along the vector A, because it is 2t _dm, is x = 2t _dm. That is, the time Delta] t _sm observed on clock domain _{f m} corresponding to the clock domain _{f s} on the observed time Delta] t _s, at 11, the observation time vector ^{_{(f m, Δt sm) T}} ( hereinafter, the vector also referred to as a _m.) represented by. Bottom y on the clock domain _{f m} of the triangle (O point of FIG. 11, P, triangles are connected by _{Q m)} spanned by the vectors _{A m} and the vector B, when considered in the same manner as FIG. 8, is _{2t dm} .. This base y is equal to the base x because the _{line segment PP s} and the line segment QQ _{m in FIG. 11 are parallel to each other.} Therefore, it can be seen that the base x = 2t _dm.

Further, the time difference t _{0 m} on the clock domain fm is the midpoint of the base y when considered in the same manner as in FIG. 8, and can be obtained by the equation (14).
t _{0 m} = Δt _m −t _dm … (14)

As described above, it was found that the propagation times t _ds and t _dm are represented by the area a of the wave number region S. Since this area a can be obtained by dividing the magnitude of the outer product of the vector A and the vector B by 2, the propagation times t _ds and t _dm can be obtained according to the equations (15) and (16). ..

_{t ds = | (f s,} Δt s) T × (f m, ΔT m) T | / (2 × f m) ... (15)
_{t dm = | (f s,} Δt s) T × (f m, ΔT m) T | / (2 × f s) ... (16)

[1-2-2. Frequency f _m , f _s , transmission / reception interval Δt _m , transmission / reception interval Δ t _s ]
As described above, the propagation time _{t ds, t dm,} the area of the wave number region a, the frequency _f m, depending on the _{f s,} the area a is, the frequency _f m, _{f s,} reception interval Delta] t _m, reception and transmission interval Delta] t _s Depends on. Therefore, it is necessary to obtain these values in order to obtain the propagation time.

(1) Transmission / reception interval Δt _m , transmission / reception interval Δt _s
The transmission / reception interval Δt _m is obtained by the transmission / reception interval calculation unit 83. That is, as shown in FIG. 5, the transmission / reception interval calculation unit 83 calculates the difference between the reception time of the synchronization information from the slave device 1b and the transmission time of another synchronization information from the master device 1a to the slave device 1b. By doing so, the transmission / reception interval Δt _m is obtained.

Receiving and transmitting interval Delta] t _s is determined by the reception and transmission interval computing unit 84. That is, as shown in FIG. 5, the transmission / reception interval calculation unit 84 calculates the difference between the transmission time of the synchronization information from the slave device 1b to the master device 1a and the reception time of another synchronization information from the master device 1a. Request receiving and transmitting interval Delta] t _s by.

(2) frequency _f m, _{f s}
The frequencies f _m and f _s are obtained by the counter 40 and the frequency acquisition unit 82. That is, as shown in FIG. 4, the master device 1a transmits at least twice synchronization information to the slave device 1b in the transmission interval [Delta] T _m. At that time, the counter 40 of the master device 1a counts the number of pulses _{p m} of the clock 20 of the master device 1a in the transmission interval [Delta] T _m. When this transmission interval [Delta] T _m and 1 second, the number of pulses p _m is one that frequency f _m. Alternatively, even if the transmission interval ΔT _{m is set} to a time other than 1 second, it may be converted into the number of pulses per second. _{That, p m: ΔT m = f} m: from 1, the frequency _{f m can} be determined by _{f m = p m / ΔT m} . In other words, the number of pulses p _m, the transmission interval [Delta] T _m, because it is observable quantities, can be frequency acquisition unit 82 to obtain a frequency f _m by obtaining the number of pulses p _m.

Further, as shown in FIG. 4, when the master device 1a transmits the synchronization information twice, the slave device 1b receives the synchronization information twice. At that time, the counter 40 of the slave device 1b counts the number of pulses _{p s} clock 20 of slave device 1b in the reception interval [Delta] T _s. The reception interval ΔT _s is a time interval corresponding to the transmission interval ΔT _m , and the number of pulses _ps is the frequency f _s . Alternatively, even if the transmission interval ΔT _m is a time other than 1 second, it may be converted into the number of pulses per second. That is, from p _s : ΔT _s = f _s : 1, the frequency f _s can be obtained by f _s = p _s / ΔT _s. That is, since the pulse number p _s and the reception interval ΔT _s are observable quantities, the frequency acquisition unit 82 can obtain the frequency f _{s by acquiring the pulse number p s.}

The synchronization information transmitted by the master device 1a here is information transmitted to obtain frequencies fm and fs, and the contents thereof are arbitrary.

[1-3. motion]
The operation of the information communication system 100 of the present embodiment will be described with reference to FIG. FIG. 12 is an example of an operation flowchart of the information communication system 100.

As shown in FIG. 12, first, the slave device 1b transmits a signal requesting synchronization with the master device 1a (hereinafter, also referred to as a synchronization request signal) to the master device 1a by the synchronization request unit 80 (step S01). : Sync request).

When the master device 1a receives the synchronization request signal, the master device 1a transmits two synchronization information to the slave device 1b, and the counter 40 and the counter control unit 76 pulse the clock 20 _{at the transmission interval ΔT m of the synchronization information.} a count _{p m,} and transmits the number of pulses _{p m} to the slave device 1b through the transmitter 11 (step S02: counting and transmission of the pulse number _{p m).} The pulse number _{p m,} the frequency acquisition unit 82 of the slave device 1b obtains.

The slave device 1b receives two synchronization information from the master device 1a, the counter 40 and counter control unit 81 counts the number of pulses _{p s} clock 20 in reception intervals [Delta] T _s of the synchronization information (step S03: count the number of pulses _{p s).} The number of pulses _{p s,} the frequency acquisition unit 82 acquires. Here, the transmission interval ΔT _{m is set} to 1 second. That is, since the pulse numbers p _m and p _s are the frequencies f _m and f _s , the frequency acquisition unit 82 obtains the frequencies f _m and f _{s by acquiring the pulse numbers p m} and p _s .

Then, send and receive synchronization information between the master device 1a and the slave device 1b, and calculates a reception interval Delta] t _m and reception and transmission interval Delta] t _s (Step S04: transmission and reception intervals Delta] t _m, calculation of reception and transmission interval Delta] t _s ).

Specifically, as shown in FIG. 5, the master device 1a transmits synchronization information to the slave device 1b. At that time, the time recording unit 74 _{puts the transmission time t m1} corresponding to the transmission timing of the synchronization information on the synchronization information. The slave device 1b receives the synchronization information, and the transmission / reception interval calculation unit 83 acquires _{the transmission time t m1 included in the synchronization information.} Further, the reception / transmission interval calculation unit 84 acquires _{the reception time t s1 of the synchronization information.}

After receiving the synchronization information, the slave device 1b transmits another synchronization information to the master device 1a. The transmission / reception interval calculation unit 84 acquires the transmission time t _{s2 at that time.} The master device 1a receives the other synchronization information and _{transmits the reception time t m2} to the slave device 1b. As a result, the transmission / reception interval calculation unit 83 acquires the _{reception time t m2.}

The transmitting and receiving interval calculating unit 83 obtains the reception time t _{m @ 2} of another synchronization information, the reception interval Delta] t _m by calculating a difference between the transmission time t _m1 synchronization information. Receiving and transmitting interval calculating unit 84 obtains the sending time t _s2 of another synchronization information, the receiving and transmitting interval Delta] t _s by calculating the difference between the reception time t _s1 the synchronization information.

Then, the area calculation section 85, transmission and reception interval Delta] t _m, reception and transmission interval Delta] t _s, the frequency _f m, from _{f s,} and calculates the area a wavenumber region (Step S05: Calculation of the area of the wave number region). Propagation time calculation unit 86 calculates the propagation time t _dm by dividing the area a calculated by the area calculation section 85 at the frequency f _m (Step S06: Calculation of the propagation time). Time difference calculating portion 87 calculates the time difference _{t 0 s} by adding a propagation time _{t ds} calculated by the propagation time calculating unit 86 and the reception and transmission interval Delta] t _s (Step S07: Calculation of time difference). Then, the synchronization control unit 88 corrects the time of the clock 30 of the slave device 1b based on _{the time difference t 0s} calculated by the time difference calculation unit 87, and synchronizes with the master device 1a (step S08: synchronization). For example, if the time difference t _0s > 0, the synchronization control unit 88 sets _{the time obtained by subtracting the time difference t 0s} from the time output by the clock 30 of the slave device 1b as the time of the slave device 1b.

[1-4. effect]
(1) The information communication system 100 of the present embodiment is an information communication system in which the slave device 1b synchronizes with the master device 1a by information communication, and the master device 1a and the slave device 1b transmit information. It has a device 11, a receiver 12 for receiving information, a clock 20 that oscillates at a predetermined frequency and gives operation timing of each part in the device, and a clock 30 that ticks from the clock 20 as a source. The slave device 1b includes a propagation time calculation unit 86 that calculates _{the propagation time t ds} of the information transmitted between the master device 1a and the slave device 1b, and the master device 1a and the slave device 1b based on the _{propagation time t ds.} A time difference calculation unit 87 that calculates the time _{difference t 0s} between the two, _{and a synchronization control unit 88 that performs synchronous control based on the time difference t 0s} are provided, and the master device 1a transmits information to the slave device 1b to transmit the information. The slave device 1b receives, the slave device 1b transmits another information to the master device 1a, the master device 1a receives the other information, and the transmission / reception from the transmission of the information in the master device 1a to the reception of another information. the interval Delta] t _m, receiving and transmitting interval Delta] t s from the reception of information in the slave device 1b to the transmission of other _information, the master device 1a frequency f _m of the _clock, the frequency of the clock of the slave device 1b and f _s, the horizontal axis is frequency, the vector and the vertical axis in the two-dimensional plane is a time a, the vector _{B (f s, Δt s)} T, (f m, Δt m) when ^{T, the} propagation time calculating section 86, 2 the area a wavenumber region S of the triangle formed by the vectors a and B mapped by the dimension plane, and to calculate the propagation time t _ds by dividing the clock frequency f _m of the master device 1a.

As a result, even if the clock frequencies of the master device 1a and the slave device 1b are different, synchronization can be performed with high accuracy. That is, since the clock frequencies are different, it is necessary to measure the time with reference to one of the clock frequencies. For example, it illustrated as a comparative example, if you want a reference clock frequency f _s of the slave device 1b, it is necessary to convert the time or time in the master device 1a in time or time in the slave device 1b. When the time slave device 1b corresponding to the time Delta] t _m of the master device 1a to Delta] t _ms, conversion formula becomes Δt _ms = r × Δt _m. Here, r is the frequency ratio, i.e., a clock frequency _{f s} of the slave device 1b with respect to the clock frequency _{f m} of the master device _{1a (r = f s / f} m), it is necessary to obtain the frequency ratio r.

On the other hand, in the present embodiment, as described above, the propagation time based on the desired clock frequency can be obtained by dividing the area a by the clock frequency for which the influence is to be removed by equal area conversion. Knowledge has been obtained. That is, by equal area conversion, it is possible to directly obtain the propagation time based on the desired clock frequency without obtaining the conversion formula (frequency ratio) of the time itself. Therefore, the number of operations can be suppressed. As a result, the occurrence of rounding error that occurs during calculation can be suppressed, and high-precision synchronization can be achieved. For example, in the case of the above comparative example, (1) the frequency ratio r is obtained, (2) Δ t _ms is obtained by time conversion, and (3) the propagation time t _ds (= (Δ _{t ms − Δ t s} ) / 2) is obtained. , However, according to the present embodiment, only two steps of (I) finding the area a and (II) finding the propagation time t _ds (= a / f _m ) are sufficient.

(2) The slave device 1b has an area calculation unit 85 that calculates the area a of the wave number region S by dividing the size of the outer product of the vector A and the vector B by 2. As a result, the area a can be easily obtained.

(3) The master device 1a has a counter 40 that counts the number of pulses oscillated by its own clock 20, the transmitter 11 transmits information to the slave device 1b at least twice, and the counter 40 causes the slave device 1b. The number of pulses in the transmission interval of information to is counted, the transmitter 11 transmits the number of pulses counted by the counter 40 to the slave device 1b, and the slave device 1b counts the number of pulses oscillated by its own clock 20. It has a counter 40 and _{a frequency acquisition unit 82 for acquiring frequencies f m} and f _s , the receiver 12 receives the information from the master device 1a at least twice, and the counter 40 receives the information from the master device 1a. The receiver 12 counts the number of pulses in the information reception interval, the receiver 12 receives the number of pulses of the master device 1a from the master device 1a, and the frequency acquisition unit 82 sets the number of pulses of the master device 1a and the number of pulses of the slave device 1b. The frequencies f _m and f _s were obtained from. Thereby, the clock frequencies f _m and f _s of each device 1a and 1b can be obtained.

(4) The master device 1a transmits information to the slave device 1b, the slave device 1b receives the information, the slave device 1b transmits another information to the master device 1a, and the other information is transmitted to the master device. 1a receives, the master device 1a transmits the transmission time of information and the reception time of another information to the slave device 1b, and the slave device 1b receives information from the transmission time of information and the reception time of another information. It has a transmission / _{reception interval calculation unit 83 that calculates a transmission / reception interval Δt m,} and a transmission / reception interval calculation unit 84 _{that calculates a transmission / reception interval Δt S} of another information from a reception time of information and a transmission time of another information. I did.

As a result, the calculation of the information for obtaining the area of the wave number region S is integrated in the slave device 1b, so that the burden on the master device 1a can be reduced. In particular, the burden can be reduced so that the master device 1a is synchronized with many slave devices 1b.

[2. Other embodiments]
The present invention is not limited to the above-described embodiment as it is, and at the implementation stage, the components can be modified and embodied within a range that does not deviate from the gist thereof. In addition, various inventions can be formed by an appropriate combination of the plurality of components disclosed in the above-described embodiment. For example, some components may be removed from all the components shown in the embodiments.

For example, in the above-described embodiment, in each of the devices 1a and 1b, the time recording unit 74 puts the time (transmission time) corresponding to the transmission timing on the information to be transmitted and transmits the information, but puts the information on another information. You may send it. This is because it is sufficient if the transmission time can be transmitted to the devices 1a and 1b of the synchronization partner.

100 Information communication system 1 Information communication device 1a Master device 1b Slave device 10 Communication unit 11 Transmitter 12 Receiver 13 Transmission timing detection unit 14 Reception timing detection unit 20 Clock 30 Clock 40 Counter 50 Storage unit 60 External interface 70 Control unit 71 Main Control unit 72 Transmission / reception data I / F
73 Communication control unit 74 Time recording unit 75 Scheduler 76 Counter control unit 77 Count transmission control unit 80 Synchronization request unit 81 Counter control unit 82 Frequency acquisition unit 83 Transmission / reception interval calculation unit 84 Transmission / reception interval calculation unit 85 Area calculation unit 86 Propagation time Calculation unit 87 Time difference calculation unit 88 Synchronous control unit

Claims (8)

An information communication system in which the slave device synchronizes with the master device by information communication.
The master device and the slave device
Transmitters that send information and
The receiver that receives the information and
A clock that oscillates at a predetermined frequency and gives the operation timing of each part in the device,
A clock that ticks from the clock as a source
Have,
The slave device is
A propagation time calculation unit that calculates the propagation time of information transmitted between the master device and the slave device,
A time difference calculation unit that calculates the time difference between the master device and the slave device based on the propagation time.
A synchronous control unit that performs synchronous control based on the time difference,
With
The master device transmits information to the slave device, and the slave device receives the information.
The slave device transmits another information to the master device, and the master device receives the other information.
The transmission and reception interval Delta] t m to the reception of the specific information from the transmission of the information in the master _device, the Delta] t s the reception and transmission interval from the reception of the information in the slave device to the transmission of the specific _information, the master device frequency f _m of the clock of _the slave clock frequency and f _s of the apparatus, the horizontal axis indicates the frequency, the vector and the vertical axis in the two-dimensional plane is a time a, the vector _{B (f s, Δt s)} T , when the ^{_{(f m, Δt m) T}} ,
The propagation time calculation unit
The propagation time is calculated by dividing the area of the wave number region of the triangle formed by the vector A and the vector B stretched on the two-dimensional plane by the frequency of the clock of the master device.
An information communication system characterized by. The slave device is
Having an area calculation unit that calculates the area of the wave number region by dividing the size of the outer product of the vector A and the vector B by 2.
The information communication system according to claim 1. The master device is
It has a counter that counts the number of pulses that its own clock oscillates.
The transmitter transmits information to the slave device at least twice.
The counter counts the number of pulses in the transmission interval of the information to the slave device.
The transmitter transmits the number of pulses counted by the counter to the slave device.
The slave device is
A counter that counts the number of pulses that the clock oscillates
A frequency acquisition unit that acquires the frequencies f _m and f _s,
Have,
The receiver receives the information from the master device at least twice.
The counter counts the number of pulses in the reception interval of the information from the master device.
The receiver receives the number of pulses of the master device from the master device,
The frequency acquisition unit, the frequency f _m from said number of pulses of the pulse number and the slave device of the master _device, to obtain the f _s,
The information communication system according to claim 1 or 2. The master device transmits information to the slave device, the slave device receives the information, the slave device transmits another information to the master device, and the master device receives the other information. death,
The master device transmits the transmission time of the information and the reception time of the other information to the slave device.
The slave device is
A transmission / reception interval calculation unit that calculates the transmission / reception interval of the information from the transmission time of the information and the reception time of the other information.
A transmission / reception interval calculation unit that calculates the transmission / reception interval of the other information from the reception time of the information and the transmission time of the other information.
To have
The information communication system according to any one of claims 1 to 3. An information communication device that synchronizes with other information communication devices by information communication.
Transmitters that send information and
The receiver that receives the information and
A clock that oscillates at a predetermined frequency and gives the operation timing of each part in the device,
A clock that ticks from the clock as a source
Have,
A propagation time calculation unit that calculates the propagation time of information to be transmitted to and from the other information communication device, and a propagation time calculation unit.
A time difference calculation unit that calculates the time difference between the other information and communication devices based on the propagation time, and a time difference calculation unit.
A synchronization control unit that controls synchronization with the other information communication device based on the time difference,
With
Receiving the information transmitted from the other information communication device,
Send another information to the other information communication device,
The reception interval Delta] t m to the reception of the specific information from the transmission of the information in the another information communication _apparatus, the reception and transmission interval from the reception of the information in the information communication apparatus to the transmission of the further information Delta] t _s the other frequency f _m of the clock of the information communication _apparatus, wherein the frequency of the clock information communication apparatus as f _s, the horizontal axis indicates the frequency, the vector and the vertical axis in the two-dimensional plane is a time a, the vector B ( f _s, Δt _s) ^T, when the ^{_{(f m, Δt m) T}} ,
The propagation time calculation unit
To calculate the propagation time by dividing the area of the wave number region of the triangle formed by the vector A and the vector B stretched on the two-dimensional plane by the frequency of the clock of the other information communication device.
An information communication device characterized by. Having an area calculation unit that calculates the area of the wave number region by dividing the size of the outer product of the vector A and the vector B by 2.
5. The information communication device according to claim 5. A counter that counts the number of pulses that the clock oscillates,
A frequency acquisition unit that acquires the frequencies f _m and f _s,
Have,
The receiver receives the information from the other information communication device twice,
The counter counts the number of pulses in the reception interval of information from the other information communication device.
The receiver receives the number of pulses from the other information communication device at the transmission interval of information corresponding to the reception interval.
The frequency acquisition unit, the frequency f _m from said number of pulses of the pulse number and the information communication device of the other information communication _apparatus, to obtain the f _s,
The information communication device according to claim 5 or 6. Upon receiving the information transmitted by the other information communication device,
Another information is transmitted to the other information communication device,
Upon receiving the transmission time of the information and the reception time of the other information,
A transmission / reception interval calculation unit that calculates the transmission / reception interval of the information from the transmission time of the information and the reception time of the other information.
A transmission / reception interval calculation unit that calculates the transmission / reception interval of the other information from the reception time of the information and the transmission time of the other information.
To have
The information communication device according to any one of claims 5 to 7.

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