JPH0983608A - Time synchronization device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To synchronize the time of a transmission station with that of a reception station by the order of a micro second (μs) unit. SOLUTION: The transmission station 1 of a time synchronization device is provided with a transmission/reception part 11 transmitting time data which is code-converted for a time data transmission request and transmission delay time to the reception station 3, a timer part 14 measuring transmission delay time and a CPU part 12 which converts time data expressed by hexadecimal in an HDLC procedure into a code which is not zero-inserted by dinarization for the time data transmission request. The reception station 3 is provided with a transmission/reception part 31 receiving time data transmitted from the transmission station 1 and transmission delay time and a timer part 34 measuring reception delay time until time is set from when the reception of time data is completed, and a CPU section 32 in which received time data is inversely converted into the original code of hexadecimal, transmission delay time, reception delay time, transmission delay time and the frame length time of time data are added and it is set in a clock part 33 as present time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a time synchronizing device used in, for example, a power system.

[0002]

2. Description of the Related Art Conventionally, a time synchronizing device that uses HDLC transmission to perform time synchronization between electric power facilities arranged at various places is well known.

In this HDLC transmission, a special pattern is used such that the bit string of data indicates a flag in the pattern "01111110" and indicates an abort in the pattern "11111111".

In distinguishing these special patterns from bit strings of general data, "1" of general data is 6
It is necessary to avoid lining up more than one in a row.
In the C transmission procedure, the bit string "1" is included in general data.
There is a rule to automatically insert "0" when there are 5 or more consecutive.

For example, when a certain length of frame is transmitted from a certain transmitting station to a receiving station through a transmission line, the zero insertion occurs, so that the length of data in the frame changes and the frame length changes.

Therefore, the timing of reception completion at the receiving station is not constant and accurate time synchronization is difficult.

Also, when a device such as a relay device that causes a transmission delay or a long-distance transmission line is interposed between the transmitting station and the receiving station, the delay time between them is not known, and in this case as well, the accuracy is high. Good time synchronization was difficult.

The operation of the conventional time synchronizer for synchronizing the time between the transmitting station and the receiving station will be described below.

First, software activated by an interrupt signal from a clock (which may be an external clock device) in the transmitting station reads the time from the clock and transmits the time to the receiving station. At this time, the time measurement unit (for measuring the transmission delay time) is activated by the interrupt signal from the clock and the time measurement is stopped when the transmission / reception unit starts the transmission.

On the other hand, at the receiving station, when the reception of the frame containing the time data is completed, an interrupt signal from the transmitting / receiving section is generated. This signal activates the timer unit (for measuring the reception delay time). Further, the software of the receiving station takes out the time data from the timer unit and notifies the transmitting station of the completion of receiving the time data.

The transmitting station which has received the reception completion notice is
The measured transmission delay time is transmitted to the receiving station.

When the receiving station receives this transmission delay time,
The time measurement unit is stopped at the timing to set the time, the time is taken out, and the time data and the transmission delay time and (the estimated value of the transmission delay time and the approximate value of the transmission frame long time) are added to set the time. To do.

By the way, as a system utilizing the HDLC transmission, there is an electric power system in which a plurality of power plants are connected and controlled by communication lines.

In this type of electric power system, when a failure or a failure occurs at a plurality of power stations, the occurrence time of the failure or the failure and the propagation route of the failure are checked based on the accident history of each power station. , The failure source and the failure source are investigated and recovery measures are taken. In this case, it is necessary to promptly recover the power after the power facility is stopped, and in particular, to check the spread route of the failure, it is necessary to confirm the time on the order of at least microseconds.

However, in such a power system, even if the above-mentioned time synchronizer is used to send time information to each power plant, the transmission delay time and the transmission frame length are not constant, so that time synchronization in the microsecond order is performed. Is difficult and
It is the current situation that a great deal of time is spent investigating the source of failure and the source of failure.

[0016]

As described above, in the above-described conventional time synchronizing device, the time synchronization with the receiving station located at a different point from the transmitting station cannot be performed in the order of microseconds, and therefore, in particular, the power system and the like. However, there is a problem in that the time difference occurs at each power plant when an accident occurs and it takes a lot of time to investigate the cause.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a time synchronization device capable of time synchronization on the order of microseconds between a transmitting station and a receiving station.

[0018]

In order to achieve the above object, a time synchronizing device according to claim 1 transmits information between a transmitting station and a receiving station connected on a transmission line based on an HDLC procedure. In the information transmission device,
When the time setting request is received from the reception station, the transmission delay time measuring unit that measures the transmission delay time from receiving the time setting request and starting transmitting the time information from that time,
The time information represented by hexadecimal numbers in the HDLC procedure is
Code conversion means for converting into a code that does not insert zero by binarization, time information code-converted by the code conversion means, and transmission delay time measured by the transmission delay time measuring means are transmitted to the receiving station. And a receiving unit that receives the time information and the transmission delay time transmitted from the transmitting station.
The reception delay time measuring means for measuring the reception delay time from the completion of reception of the time information by the reception means to the time setting, and the time information received by the reception means as the original 1
Code inverse conversion means for inverse conversion into a hexadecimal code, time information inversely converted by the code inverse conversion means, the transmission delay time, the reception delay time, the transmission delay time on the transmission path, and the time It is characterized by comprising an adding means for adding the information frame long time and a time setting means for setting the value of the time information added by the adding means as a current time in a predetermined clock section.

In this case, since the time information to be transmitted is converted into a code such that zero is not inserted at the time of binarization, it is binarized from the transmitting means and then transmitted, so that zero is not inserted at the time of transmitting the time information and the time information is transmitted. The frame length does not change, and the frame time t3 of the time information becomes constant.

Therefore, when the time information is transmitted to the receiving station through the transmission line, the time information includes the transmission delay time t1 and the transmission delay time t2 which is the delay time on the transmission line.
By adding the frame long time t3 and the reception delay time t4, the time synchronization between the transmitting station and the receiving station can be almost accurately achieved in the order of microseconds. The time synchronization device according to claim 2 is the time synchronization device according to claim 1, wherein the code conversion means of the transmitting station is 1
It is characterized in that when the time information represented by a hexadecimal number is binarized, it is converted into a code in which 6 or more 1 bits are not continuously arranged.

In the HDLC procedure, if the number of 1's is 5 or less, the zero insertion operation is not performed. Therefore, zeros are not inserted in the converted code, and the frame long time t3 becomes a fixed value.

Therefore, the time synchronization between the transmitting station and the receiving station can be achieved almost accurately in the order of microseconds.

Further, in the time synchronization device according to the present invention, the time information is transmitted from the transmitting station to the receiving station based on the HDLC procedure when the time setting request is generated between the transmitting station and the receiving station connected on the transmission line. In the time synchronization device for setting the sending time, the transmitting station receives the time setting request and measures a transmission delay time from when the transmitting station receives the time information until it starts transmitting, and a time for the time setting request. Information, and a transmission means for transmitting the transmission delay time measured by the measuring means to the transmission path, the receiving station, receiving means for receiving time information and the transmission delay time from the transmission path, A reception delay time measuring means for measuring a reception delay time from the time when the reception means starts receiving the time information to the time setting; and the time information received by the reception means. An addition means for adding the transmission delay time, the transmission delay time, and the reception delay time on the transmission path; and a time setting means for setting the value of the time information added by the addition means as a current time in a predetermined clock section. It is characterized by comprising.

In this case, since the frame long time t3 is measured including the time of the entire transmission frame, it is not affected by the change in the transmission frame length, and accurate time synchronization can be performed between the transmitting station and the receiving station.

According to a fourth aspect of the present invention, there is provided a time synchronizer which transmits time information from a transmitting station to a receiving station based on an HDLC procedure when a time setting request is issued between the transmitting station and the receiving station connected on a transmission line. In the time synchronization device that sets the sending time,
The transmitting station receives the time setting request and measures a transmission delay time from when the time setting request is transmitted until the time information is completely transmitted; time information for the time setting request; and the transmission delay time measuring means. And a transmission means for transmitting the transmission delay time measured by the above to the transmission path, wherein the receiving station receives the time information and the transmission delay time from the transmission path, and the reception means transmits the time information. Reception delay time measuring means for measuring the reception delay time from the end of reception to the time setting, and the time information received by the receiving means, in the transmission delay time on the transmission path, the transmission delay time, and the reception delay time. And an adding means for adding and a time setting means for setting the value of the time information added by the adding means as a current time in a predetermined clock section. It is characterized in that.

In this case, since the transmission delay time t1 is measured including the length of the entire transmission frame, the transmission delay time t1 is not affected by the change in the transmission frame length, and the time synchronization between the transmitting station and the receiving station is almost accurately achieved. be able to.

According to a fifth aspect of the present invention, there is provided a time synchronizer which transmits time information from a transmitting station to a receiving station based on an HDLC procedure when a time setting request is issued between the transmitting station and the receiving station connected on a transmission line. In the time synchronization device that sets the sending time,
The transmitting station sends a loopback command to the receiving station through the transmission line, and a loopback command transmitting means, and after transmitting the loopback command, the transmitted data is transmitted through the transmission line in a loopback state. The receiver includes a loopback time measuring means for measuring a time until returning to the station, and a transmitting means for transmitting the loopback time and time information measured by the loopback time measuring means to the transmission path, The station receives the loopback command, the loopback time and the time information from the transmission path, and switches the transmission path into the loopback state based on the loopback command received by the receiving means. Means and the transmission path switching means to release the loopback state, and then the receiving means transmits through the transmission path. Based on the received loopback time, the calculating means calculates the transmission delay time required for the time information to reach the receiving station, and the time information received by the receiving means, calculated by the calculating means. The present invention is characterized by including an adding means for adding the transmission delay time and a time setting means for setting the value of the time information added by the adding means as a current time in a predetermined clock section.

In this case, the transmission path is switched to the loopback state by the transmission path switching means on the receiving station side, and then the frame is transmitted from the transmission means. At this time, the time measurement of the timer unit starts at the timing when the beginning of the frame appears on the transmission path,
When the frame is looped back at the receiving station and returned, the frame is stopped and the loopback time is obtained. 1 / of this time
2 is the one-way transmission delay time t2.

Therefore, even when the transmission delay time t2 changes on the transmission line or when it changes through the relay device, this time can be obtained almost accurately.

A time synchronization device according to a sixth aspect of the invention is the time synchronization device of the third aspect.
The time synchronization device according to any one of claims 1 to 5, further comprising the code conversion means and the code inverse conversion means according to claim 1.

As a result, since the frame long time t3 becomes constant, more accurate time synchronization can be achieved.

The points of the inventions of claims 2 to 5 are that the transmitting station and the receiving station are provided with a frame head detecting section for detecting the frame head of the time data, a frame end detecting section for detecting the frame end, and their respective times. There is a timer part to measure. Then, a flag pattern that is a special bit string is detected from one frame,
By capturing the boundary between the flag pattern and other patterns, the length of the time data itself is obtained.

[0033]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

First, a time synchronizing apparatus according to the first embodiment of the present invention will be described with reference to FIGS. FIG.
FIG. 2 is a diagram showing a configuration of a time synchronization device according to a first embodiment of the present invention, and FIG. 2 is a diagram showing a table for performing code conversion of hexadecimal values from “0” to “F” in this time synchronization device. FIG. 3 is a diagram showing a combination of six or more “1” s, and FIG. 4 is a timing chart showing the operation of the time synchronizer.

In FIG. 1, this time synchronizing device is configured by arranging a relay device 2 between a transmitting station 1 and a receiving station 3 and connecting them via transmission lines 4 to 7. .

The transmitting station 1 includes a transmitting / receiving section 11 and an MPU section 1
2, a clock unit 13, a timer unit 14, etc. The transmission / reception unit 11 serially converts the transmission data given from the MPU unit 12 and sends it to the transmission line 4. MPU part 1
2 is a part where the software for time synchronization operates. The clock unit 13 is a circuit that generates time, for example, 1
An interrupt signal 22 is generated at time synchronization timing such as every minute. The timer unit 14 starts time measurement by the interrupt signal 22 from the clock unit 13 and stops time measurement by the transmission start signal 21 from the transmission / reception unit 11 to obtain the transmission delay time t1. The receiving station 3 includes a transmitting / receiving unit 31 and an MPU.
It includes a unit 32, a clock unit 33, a timer unit 34, and the like. The transmission / reception unit 31 converts the serial data from the transmission path 5 into parallel data and supplies it to the MPU unit 32. MPU section 32
Is the part where the software for time synchronization operates. The clock unit 33 is a circuit for generating time, and the time is set in synchronization with the clock unit 13 of the transmitting station 1. Timer unit 34
Starts time measurement by an interrupt signal 36 from the transmitter / receiver 31 and a timer stop signal 37 from the MPU 32.
The time measurement is stopped by and the reception delay time t4 is obtained.

As shown in FIG. 2, the MPU section 32 has a code conversion table 20. Based on this table 20, the values from 0 to F in hexadecimal are code-converted and received by the transmission / reception section 31. hand over.

Normally, the hexadecimal number from "0" to "F" can be represented by a 4-bit binary number. Therefore, on this table 20, combinations of "1" exceeding 5 consecutive numbers are shown in FIG. As shown in, hexadecimal "FF",
"FE", "FD", "FC", "3F", "7F",
It becomes "BF" and "7E".

Therefore, if "F" and "7" are replaced with different codes, it will be understood that "1" cannot exceed 5 consecutively and cannot be connected.

In this case, since 4 bits cannot be converted into another code, 1 bit is added and represented by 5 bits.

If these 5 bits are code-converted on the table 20, there will be no more than 6 consecutive "1" s in all combinations.

In the HDLC procedure, there is a rule to insert "0" in the bit data when the number of "1" exceeds 5 in succession. It will not be inserted and the frame length will not change.

The operation of this time synchronizer will be described below.

In the case of this time synchronizer, data transmission is performed based on the HDLC procedure.

As shown in FIG. 4, first, the clock unit 13 of the transmitting station 1 generates an interrupt signal 22 at that timing. With this signal, the value of the timer section 14 is once reset to 0 and restarted.

Further, the software of the MPU section 12 receives the interrupt signal and starts the processing for time synchronization.

In this case, the MPU unit 12 reads the time from the clock unit 13, assembles it into a time synchronization frame, and sets it in the transmission / reception unit 11.

Then, the transmitting / receiving section 11 starts transmitting the frame to the transmission path 4. The transmission start signal 21 is output to the timer unit 14 at the same timing as this. Receiving this, the timer unit 14 stops the measurement of the time t1 during the measurement. The transmitting station 1 is now in a waiting state for receiving an acknowledge frame from the receiving station 3.

When the transceiver station 31 receives the time data from the transmitter station 1, the receiver station 3 outputs an interrupt signal 36 to the timer section 34 at that timing. The timer 36 is once reset to 0 by this signal 36 and restarted.

Further, the software of the MPU section 32 receives the interrupt signal 36 and starts the processing for time synchronization.

In this case, the MPU unit 32 has the transmitting / receiving unit 3
The time data is read from 1 and an acknowledge frame is set in the transmission / reception unit 31 to inform the transmitting station 1 that the reception is completed, and during the time t1 from the transmitting station 1, it waits for the reception of the frame.

Upon receiving the acknowledge frame from the receiving station 3, the transmitting station 1 extracts the time t1 from the timer section 14, assembles it into a frame, and sets it in the transmitting / receiving section 11. Upon receiving this frame, the receiving station 3 receives the MPU unit 32.
Starts the time setting process for the clock unit 33.

In this case, the MPU unit 32 receives the received time data and the transmission delay time t when transmitting the time data.
1 and the frame long time t3 of the time data (a fixed value because zero is not inserted) and the transmission delay time t2 are added to the time of the time setting timing, and the value of the timer unit 34 stopped is added to the clock unit 33. Set to.

As described above, according to the time synchronizing apparatus of the first embodiment, zero is no longer inserted in the frame to be transmitted, and the frame long time t3 becomes a fixed value. Therefore, the receiving station 3
Although there is a possibility that the time set in the clock unit 33 of the above will be deviated from the time of the transmitting station by the oscillation timing of the crystal oscillator, they almost match in the microsecond order, and accurate time synchronization is achieved between the transmitting station and the receiving station. be able to.

That is, the influence of the change in the frame length of the transmission frame due to the zero insertion and the influence of the transmission delay due to the relay device on the transmission line can be eliminated, and the receiving station can perform the highly accurate time synchronization on the microsecond order through the transmission line. Like

For example, by applying to each place that requires highly accurate time synchronization such as an electric power system, when an accident occurs at a certain power plant, the accident history is retrieved from each power plant and the cause is investigated from each time information. You will be able to quickly.

Since the hardware (timer unit, frame head detection unit, frame end detection unit, etc.) may be existing ones, it is possible to realize highly accurate time synchronization at low cost. Next, referring to FIGS. 5 and 6, the second embodiment of the present invention will be described.
The time synchronization device of the embodiment will be described. FIG. 5 is a diagram showing the configuration of the time synchronization device of the second embodiment according to the present invention, and FIG. 6 is a timing chart showing the operation of this time synchronization device.

The description of the configuration here will be made with a difference from the configuration of the first embodiment.

In the case of the first embodiment, the timer unit 14 is stopped by the transmission start signal 21 from the transmitting / receiving unit 11, but as shown in FIG. 5, in the second embodiment. The time synchronizer has a frame head detector 15, from which a timer stop signal 24 is transmitted.

Further, the timer section 34 is started by the interrupt signal 36 from the transmitting / receiving section 31 in the first embodiment, whereas in the time synchronizing apparatus of the second embodiment, the frame head is detected. It is a timer start signal 39 from the section 38. With this time synchronizer,
When an interrupt signal 22 for time synchronization is generated from the clock unit 13 of the transmitting station 1 at the timing shown in FIG. 6, the time of the timer unit 14 is once set to 0 by the interrupt signal 22.
It is reset to and restarts.

Further, the software of the MPU section 12 receives the interrupt signal 22 and starts the processing for time synchronization.

In this case, the MPU section 12 reads the time from the clock section 13, assembles it into a time synchronization frame, and sets it in the transmission / reception section 11.

Then, the transmitter / receiver 11 starts transmitting the frame to the transmission path 4. At the same time, the frame head detector 15 outputs a timer stop signal 24 to the timer 14 at the timing of the time chart shown in FIG. Upon receiving the timer stop signal 24, the timer unit 14 stops measuring the time t1 during the measurement. The transmitting station 1 is now in a standby state for receiving an acknowledge frame from the receiving station 3. In the receiving station 3, when the time data from the transmitting station 1 is received by the transmitting / receiving unit 31, the frame head detecting unit 38 detects the head of the frame, and the timer unit 34 outputs the timer start signal 39 at the timing of the time chart shown in FIG. Output to. This timer start signal 39
Thus, the timer unit 34 is once reset to 0 and restarted.

Further, the software of the MPU section 32 receives the interrupt signal 36 and starts the processing for time synchronization.

In this case, the MPU unit 32 has the transmitting / receiving unit 31.
The transmitter / receiver 31 transmits an acknowledge frame to read the time data and notify the transmitting station 1 that the reception is completed.
Is set to, and during a transmission delay time t1 from the transmission station 1, the frame is in a reception waiting state. Upon receiving the acknowledge frame from the receiving station 3, the transmitting station 1 receives the acknowledge frame from the timer unit 14.
Then, the transmission delay time t1 is extracted, assembled into a frame, set in the transmission / reception unit 11, and transmitted from the transmission / reception unit 11.

When the receiving station 3 receives a frame through the transmission path 4, the relay device 2 and the transmission path 5, the MPU section 3
2 starts the time setting process for the clock unit 33.

In this case, the MPU unit 32 measures the total value of the received time data, the transmission delay time t1 and the transmission delay time t2, and further, the measured value of the timer unit 34 stopped at the timing of the time setting of FIG. Clock part 3 with t3 added
Set to 3.

As described above, according to the time synchronizing apparatus of the second embodiment, the transmitting station 1 and the receiving station 3 detect the frame head of the frame including the time data, and delay the frame according to the frame length. Since the time is obtained and the delay time is added to the time data at the receiving station 3 to set the time, accurate time synchronization is performed on the order of microseconds between the transmitting station and the receiving station as in the first embodiment. Can be taken.

Next, a time synchronizing apparatus according to the third embodiment of the present invention will be described with reference to FIGS. 7 and 8.
FIG. 7 is a diagram showing the configuration of the time synchronization device of the third embodiment according to the present invention, and FIG. 8 is a timing chart showing the operation of this time synchronization device.

The description of the configuration here will be made with a difference from the configuration of the first embodiment.

In the case of the first embodiment, the timer unit 14 is stopped by the transmission start signal 21 from the transmission / reception unit 11, but as shown in FIG. In the synchronizer, the timer stop signal 24 from the frame end detector 16 is used.

As shown in FIG. 8, in the case of this time synchronizer, when the interrupt signal 22 is generated from the clock unit 13 of the transmitting station 1 at the timing of the time chart shown in FIG. The time is once reset to 0 and restarted. Further, the software of the MPU unit 12 receives the interrupt signal 22 and starts the process for time synchronization.

In this case, the MPU unit 12 has the transmitting / receiving unit 11
The time data is read out, assembled into a time synchronization frame, and set in the transmitter / receiver 11.

Then, the transmitting / receiving section 11 starts transmitting the frame on the transmission path 4. When the frame end detector 19 detects this frame end, the timer stop signal 24 is output. Receiving this, the timer unit 14 stops the measurement of the time t1 during the measurement. The transmitting station 1 is now in a state of waiting for reception of an acknowledge frame from the receiving station 3.

When the receiving station 3 receives the time data from the transmitting station 1 at the transmitting / receiving section 31, it outputs the interrupt signal 36 to the timer section 34 at the timing of the time chart of FIG. The timer 36 is once reset to 0 by this signal 36 and restarted. Further, the software of the MPU unit 32 receives the interrupt signal 36 and starts processing for time synchronization.

In this case, the MPU unit 32 has the transmitting / receiving unit 31.
The transmitter / receiver unit 3 sends an acknowledge frame to read the time data and notify the transmitting station 1 that the reception is completed.
It is set to 1, and during the time t1 from the transmitting station 1, it waits for a frame to be received.

When the transmitting station 1 receives the acknowledge frame from the receiving station 3, it extracts the time t1 from the timer unit 14, assembles it into a frame, and sets it in the transmitting / receiving unit 11.
The frame is transmitted from the transmission / reception unit 11.

When the receiving station 3 receives this frame, the MPU unit 32 starts the time setting process for the clock unit 33.

In this case, the MPU unit 32 has already received the time data, the time data of the time t1, and the time transmission delay t.
2 is added to the time obtained by adding the value of the timer unit 34 stopped at the timing of the time set in FIG.
Set to 3.

As described above, according to the time synchronizing device of the third embodiment, the transmitting station 1 and the receiving station 3 detect the frame end of the frame including the time data and delay the frame end according to the frame length. Time is obtained, and the delay time is calculated by the receiving station 3
Since the time is set by adding to the time data with,
Similar to the embodiment described above, accurate time synchronization can be achieved on the order of microseconds between the transmitting station and the receiving station.

Specific examples of the frame head detector 15 of the second embodiment and the frame end detector 16 of the third embodiment will be described.

As shown in FIG. 9, the frame head detecting unit 15, the frame end detecting unit 16 and the like include a modem 101, a shift register 102, a counter 103 for counting up from 0 to 7, AND gates 104a, 10a.
4b, flip-flop 105 and OR gate 106
Etc.

In this case, the modem 101 first converts the signal on the transmission line 107 into the data signal 108 and the clock signal 10.
Divide into 9. Then, the data signal 108 is sent to the clock 10
At 9, the shift register 102 is sequentially shifted in. “011” appears on the parallel outputs Q1 to Q8 of the shift register 102.
When a bit pattern (flag pattern) of 11110 "appears, a signal" 1 "is output from the AND gate 104a to the flip-flop 105 and the OR gate 106.

The OR gate 106 outputs the signal "1" to the counter 103 when this signal "1" is input, and clears the value of the counter 103 to zero. Further counter 103
Becomes 0 after clearing the count value from 0 to 7.

After that, the counter 103 counts up from 0 to 7, and when the value of the counter 103 reaches 7, AN
Signal 1 from D gate 104b to flip-flop 105
“1” is output to 13. When “1” of the signal 113 is input to the flip-flop 105, the value of the signal 114 is stored in the flip-flop 105.

As described above, the output signal 115 from the flip-flop 105 changes to "1" during the flag pattern (when "F" is input) and changes to "0" when there is any other than the flag pattern. When a flag pattern other than the flag pattern is used, the value changes from "0" to "1".

Therefore, the changing point of this signal 115 from "1" to "0" indicates the beginning of the frame, and the changing point of "0" to "1" indicates the end of the frame.

Next, a time synchronizing apparatus according to the fourth embodiment of the present invention will be described with reference to FIGS. 10 and 11. FIG. 10 is a diagram showing the configuration of the time synchronization device of the fourth embodiment according to the present invention, and FIG. 11 is a timing chart showing the operation of this time synchronization device.

As shown in FIG. 10, the transmitting station 1 of this time synchronizer includes a frame head detecting section 15 for detecting the head of the frame output on the transmission path 4, and a timer section 14 for starting the head detecting operation. , A frame head detector 17 that detects the head of the frame returned through the transmission path 7 and stops the timer unit 14.

The receiving station 3 switches the switches 40 and 41 for returning the frame from the transmission line 5 to the transmission line 6.
And a MPU unit 42 that outputs a switching signal (command) 45
Consists of

As shown in FIG. 11, in this case, first, the switching signal 45 for the switches 40 and 41 is sent from the transmitting station 1 to the receiving station 3. Although the switch 40 is normally closed and the switch 41 is closed, the switch 40 is closed and the switch 41 is opened by the switching signal 45, and the loopback state is established.

Here, when the frame head detecting section 15 detects the head 50 of the frame to be transmitted from the transmitting station 1 at the timing of the time chart shown in FIG. 11, the timer start signal 25 is output to the timer section 14. The signal 25 resets the time of the timer unit 14 to 0 once and restarts.

This frame is transmitted from the transmission station 1 to the transmission line 4, the relay device 2, the transmission line 5, the switch 40, the transmission line 6,
When passing through a route such as the relay device 2 and the transmission line 7, the frame head detection unit 17 of the transmission station 1 detects the frame head 51 at the timing of FIG. 11, and outputs the timer stop signal 26 to the timer unit 14. Output timer section 14
Stop time measurement of.

Since the value of the timer unit 14 is the round trip transmission delay time including the relay device 2, this value is set to the receiving station 3
And the receiving station 3 halves the transmission delay time for one way.

When the output of the switching signal 45 is stopped, the switch 40 is opened and the switch 41 is closed by this, when the time data is transmitted from the transmitting station 1 and the time data is received by the receiving station 3, this By setting the time by adding the transmission delay time of one way, the transmitting station 1 and the receiving station 3
You can get accurate time synchronization with and.

As described above, according to the time synchronizing apparatus of the fourth embodiment, the frame is transmitted from the transmitting station 1 to the transmission line 4, the relay device 2, the transmission line 5, the switch 40, the transmission line 6, the relay device 2 and the transmission device. Since the delay time on the transmission path can be known by sending the time obtained by rotating the path such as the path 7 to the receiving station 3, time synchronization between the transmitting station and the receiving station has been difficult to achieve in the past. It can be taken in the order of seconds (μs).

In the second to fourth embodiments, the first
Although the code conversion as in the embodiment is not described, the code conversion is performed at the time of transmitting and receiving the time data for each, so that zero is not inserted in the frame transmitted from the transmitting station 1, so that the frame long time is not increased. t
3 is fixed, and time synchronization can be performed more accurately.

[0098]

As described above, according to the present invention, the zero insertion operation of the HDLC procedure is not performed during the time data transmission, and the frame length of the time data is fixed. By adding a long time or various delay times, time synchronization can be almost accurately achieved between the transmitting station and the receiving station in the order of microseconds.

Further, the transmission delay time of the frame can be accurately obtained by accurately detecting the frame head and the frame end of the time data, and the transmission delay time is added to the time data on the receiving station side, so that the transmission station The time synchronization between the receiving station and the receiving station can be performed almost accurately on the order of microseconds.

Further, even when the transmission delay time changes due to a hardware factor on the transmission line, this time can be obtained almost accurately by obtaining the loopback time of a certain frame. The time synchronization can be done almost accurately on the order of microseconds.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a time synchronization device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a code conversion table of this time synchronization device.

3 is a hexadecimal number of the code conversion table of FIG.
It is a figure which shows the combination in which 1 becomes 6 or more continuously with evolution.

FIG. 4 is a timing chart showing the operation of this time synchronization device.

FIG. 5 is a diagram showing a configuration of a time synchronization device according to a second embodiment of the present invention.

FIG. 6 is a timing chart showing the operation of this time synchronization device.

FIG. 7 is a diagram showing a configuration of a time synchronization device according to a third embodiment of the present invention.

FIG. 8 is a timing chart showing the operation of this time synchronization device.

FIG. 9 is a diagram showing a specific example of a frame head detection unit of the time synchronization device of the second embodiment and a frame end detection unit of the time synchronization device of the third embodiment.

FIG. 10 is a diagram showing a configuration of a time synchronization device according to a fourth exemplary embodiment of the present invention.

FIG. 11 is a timing chart showing the operation of this time synchronization device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Transmitting station, 2 ... Relay apparatus, 3 ... Receiving station, 4-7 ... Transmission path, 11, 31 ... Transmitting / receiving section, 12, 32 ... MPU section, 1
3, 33 ... Clock section, 14, 34 ... Timer section, 15, 3
8 ... Frame start detection unit, 23, 35 ... Data bus, 1
5 ... Frame start detection unit, 16 ... Frame end detection unit.

Claims (6)

[Claims] 1. A time synchronizer for transmitting time information from a transmitting station to a receiving station based on an HDLC procedure when the time setting request is generated between the transmitting station and the receiving station connected on the transmission line, and setting the time. The transmitting station receives the time setting request and measures a transmission delay time from when the time setting request is transmitted until the time information starts to be transmitted. Code conversion means for converting time information represented by a hexadecimal number into a code such that zero is not inserted by binarization, time information converted by the code conversion means, and the transmission delay time measurement means. And a transmission means for transmitting the transmission delay time to the receiving station, wherein the receiving station, the time information and the transmission delay time transmitted from the transmitting station A reception delay time measuring means for measuring a reception delay time from the completion of reception of the time information by the reception means to the time setting, and the time information received by the reception means as the original 16 A code reverse conversion means for reverse conversion into a code of a decimal number, and time information reverse converted by the code reverse conversion means,
An addition unit that adds the transmission delay time, the reception delay time, the transmission delay time on the transmission path, and the frame long time of the time information, and the value of the time information added by the addition unit as the current time. A time synchronization device, comprising: a time setting means for setting a predetermined clock unit. 2. The time synchronizing device according to claim 1, wherein the code converting means of the transmitting station, when binarizing the time information represented by a hexadecimal number, arranges six or more 1 bits in a row. A time synchronization device characterized by converting into a code that does not exist. 3. A time synchronizer for transmitting time information from a transmitting station to a receiving station based on an HDLC procedure when the time setting request is generated between the transmitting station and the receiving station connected on the transmission line and setting the time. The transmitting station receives the time setting request and measures a transmission delay time from when the time setting request is transmitted until the time information starts to be transmitted; time information for the time setting request; And a transmission unit configured to transmit the transmission delay time to the transmission path, wherein the receiving station receives the time information and the transmission delay time from the transmission path, and the reception unit receives the time information. A reception delay time measuring means for measuring a reception delay time from the start to the time setting, and a transmission delay on the transmission line based on the time information received by the reception means. Interval, the transmission delay time and the reception delay time are added, and time setting means for setting the value of the time information added by the adding means as a current time in a predetermined clock unit. Characteristic time synchronization device. 4. A time synchronizer for transmitting time information from a transmitting station to a receiving station based on an HDLC procedure when the time setting request is generated between the transmitting station and the receiving station connected on the transmission line, and setting the time. The transmitting station receives the time setting request and measures a transmission delay time from the reception of the time setting request until the transmission of the time information is finished, time information for the time setting request, and the transmission delay time measurement A transmission unit configured to transmit the transmission delay time measured by the unit to the transmission line, the reception station receiving the time information and the transmission delay time from the transmission line, and the reception unit time information. Reception delay time measuring means for measuring the reception delay time from the end of reception to the time setting, and the time information received by the receiving means to be set on the transmission path. An addition unit that adds the transmission delay time, the transmission delay time, and the reception delay time, and a time setting unit that sets the value of the time information added by the addition unit as a current time in a predetermined clock unit. A time synchronization device characterized in that 5. A time synchronizer for transmitting time information from a transmitting station to a receiving station based on an HDLC procedure when the time setting request is generated between the transmitting station and the receiving station connected on the transmission line, and setting the time. The transmitting station transmits a loopback command to the receiving station through the transmission line, a loopback command transmitting unit, and the transmission data transmitted after the loopback command is transmitted through a transmission line in a loopback state. A loopback time measuring means for measuring the time until returning to the own station, and a transmitting means for transmitting the loopback time and time information measured by the loopback time measuring means to the transmission path, The receiving station includes a receiving unit that receives a loopback command, a loopback time, and time information from the transmission line, and a receiving unit that receives the receiving unit. A transmission path switching means for putting the transmission path into a loopback state based on a loopback command; and a loopback received through the transmission path by the receiving means after the loopback state is released by the transmission path switching means. Calculating means for calculating the transmission delay time required for the time information to reach the receiving station based on time; and adding the transmission delay time calculated by the calculating means to the time information received by the receiving means. A time synchronization device comprising: an addition unit for setting the time information and a time setting unit for setting the value of the time information added by the addition unit as a current time in a predetermined clock unit. 6. The time synchronizing device according to claim 3, further comprising the code converting means and the code inverse converting means according to claim 1.