JPH0252284A - Time control system - Google Patents

Abstract

PURPOSE:To stop the operation of a main office time device freely by monitoring the time signal generated by a slave office time device and determining time which may be accurate, and setting the time signal of the main office time device in synchronism with the time signal of the slave office time device. CONSTITUTION:The time signal generated by the time generating device 1 of the main office time device A is modulated by a modem 2 and transmitted to slave office time devices B1-Bn through a changeover switch 4 and a transmission line 9. The device 1 or Bn compares a time signal demodulated by a modem 6 with the time signal generated by a time generating device 5 by a comparator 7 and drives the device 5 in synchronism with the device 1. Further, the device A calls the device B1-Bn upon occasion to receive the time signal generated by the device 5, compares the time signal with the time signal generated by the device 1 by a comparator 3, and monitor the accuracy of the time generated by the device B1-Bn. When the operation of the device A is stopped for maintenance inspection, the switch 4 is placed on its reception side to evade the transmission of a wrong time signal to the device B1-Bn.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a time control system that synchronizes and controls a plurality of devices installed in a distributed manner, and particularly relates to a time control system using a slave synchronization method.

(Prior art) In ground control facilities at rocket launch sites, multiple devices such as control centers, launch pads, and tracking devices are distributed and arranged, but these devices are synchronized with each other using the same and accurate time signal. control is in place. The synchronization methods between the time signal generators in each device for this purpose can be roughly classified into three types: independent synchronization, dependent synchronization, and mutual synchronization.

The independent synchronization method is a method in which each device operates completely independently, and it is a method in which it is desired to have special means for synchronizing each other. For this reason, it is necessary to install a time generator having a highly accurate atomic oscillator such as cesium or rubidium in each device, which has the disadvantage that the entire system becomes extremely expensive.

On the other hand, the mutual synchronization method is a method in which each device sends and adjusts the time signals generated by each device to achieve synchronization, so even if the accuracy of the time generator of each device is low, the system as a whole is highly efficient. You can obtain accurate time information. However, its operation is complicated, and it also has the disadvantage that if one time generator fails, the effect will be felt on the entire system.

On the other hand, the slave synchronization method is a method in which a master-slave relationship is created between devices, and the slave station time device extracts the time signal from the master station time device and drives its own time generator in synchronization with the time signal. Therefore, a highly accurate atomic oscillator is required for the main station time device, which is the backbone, but an inexpensive oscillator with relatively low accuracy can be used for the slave station time device.If there are many distributed stations, there will be no loss. It is advantageous in aspects 1 to 1. In addition, in the event of a failure of the current time signal, the destination is switched, and if the time signal is used all the time, the transmitter of that station will run on its own and synchronize independently from other areas, so the impact of failure can be minimized. .

Therefore, due to the above two advantages, the dependent synchronization method is generally used in the synchronization method.

FIG. 3 is a block diagram of a time control system according to a conventional slave synchronization method. In the figure, A is a master station time device, and the high precision time signal generated by the master station time device A is transmitted via a transmission line 9 to a plurality of slave station time devices B] to Bn.
By synchronizing the generated time signals with the time signals from the master station time device A, the slave station time devices B] to Bn obtain a highly accurate time signal equivalent to that of the master station time device A. It is something.

Here, the main station time unit WA generally has two time generators 1.14, and a high-precision atomic oscillator such as cesium or rubidium is used as a built-in oscillator in the time generator 1.14. There is. Each time generator 1.14 is connected to a modem 15 via a switch 4.

On the other hand, the subordinate time device B1 generally has one time generator 5, and the oscillator built into the time generator 5 is a relatively low-precision oscillator such as a crystal oscillator. The time generator 5 is connected to the modem 16, and the other time generators B2 to Bn have the same configuration and connection.

This system works as follows. That is, the time generating device of the main station time device A], either one of them is out of operation, and even if one of them is out of operation due to maintenance, inspection, or failure, the other is always in operation.

The time generator 1 or 14 generates a time signal, and by switching the switch 4 to the side of the time generator in operation, the time signal generated by the time generator or 14 is modulated by the modem 15. input to modem 16 via transmission line 9;

The time signal is demodulated by the modem 16, and the time generator 5 generates a time signal in synchronization with the time signal.

However, the conventional time control system described above has the following drawbacks.

In other words, the slave synchronization system is a system in which the slave station time devices B to Bn extract the time signal from the master station time device A and generate their own time signal in synchronization with the time signal, so the master station time Apparatus A was required to operate in a manner that almost eliminates operational outages, and the main station required a backup time generator in case the main station time device A malfunctioned or for maintenance and inspection of the main station. For this reason, there is a problem that not only the equipment cost increases, but also the floor space and power consumption increase.

In addition, when restarting the master station time device A after it has been stopped, it is not possible to generate the correct time simply by turning on the power, but the time must be reset (i.e., an external standard signal must be used as a reference signal). The correct time is generated only after time calibration.Here, the standard signal is J J Y
JJY is just a clock and does not contain time information, and NTT's time signal has an accuracy of several milliseconds, making it difficult to obtain accurate time.

(Purpose of the Invention) The present invention was made to solve the problems of the conventional time control system as described above. The purpose of the present invention is to provide a time control system that enables re-operation, reduces equipment costs for the main station time device, reduces floor space, and reduces power consumption.

(Summary of the Invention) In order to achieve this object, the present invention adopts the following configuration.

That is, in a slave synchronization type time control system, the master station time device monitors some or all of the time signals generated by the slave station time device, as necessary, and determines a probable time based on the time signals. By using the time information, the time signal emitted by the master station time device can be easily corrected without referring to an external standard time, or the time signal of the master station time device can be added to the time signal of the slave station time device. Configure settings to sync.

(Example) The present invention will be described in detail below based on the illustrated example.

FIG. 1 is a block diagram showing an embodiment of the present invention.

In the same figure, A is the main station time device, and the main station time device? The high-precision time signal of A is sent to a plurality of slave time devices B1 to Bn via the transmission line 9, and the slave time device B]
By synchronizing the generated time signals with the signal from the main station time device A, a highly accurate time signal equivalent to that of the main station time device A is obtained.

Here, the time device A is equipped with one time generator 1, and employs a high-precision atomic oscillator such as cesium or ruhidium as a built-in transmitter. ] is connected to a modem 2 and a comparator 3. The modem 2 consists of a modulator and a demodulator, each connected to a changeover switch 4.

On the other hand, the slave station time devices B] to Bn have the same structure as the master station, including a time generator W5, a modem 6, a comparator 7, and a changeover switch 8. The modem 2 of the master time device A and the modem 6 of the slave time device B1 are connected via a changeover switch 4.8 and a transmission line 9. Similarly, the slave time devices B2 to Bn are connected to the master time device A.

This system works as follows. That is, the time signal generated by the time generating device 1 of the master time device A is modulated by the modem 2, and transmitted via the changeover switch 4 and the transmission line 9 to the time signals of the slave time devices B1 to Bn.

The slave station time devices B1 to Bn compare the time signal demodulated by the modem 6 and the time signal generated by the time generator 5 to a comparator 7.
The time generator 5 is driven in synchronization with the time generator 1 of the main station.

Further, the master station time device A is connected to the slave station time devices B1 to B at any time.
n, receives the time signal generated by the time generator 5, compares the time signal with the time signal generated by the time generator 1 using the comparator 3, and receives the time signal from the slave time device B] or B.
The accuracy of the time at which n occurs is monitored.

On the other hand, when the operation of the master station time device A is stopped for maintenance and inspection, switch 4 of the master station time device A is switched to the receiving side to avoid sending an incorrect time signal from the slave station B] or Bn/\. Configure it like this.

During this time, the slave station time device runs on its own and is independently synchronized with other slave station time devices. Although the accuracy of the time generated by the time generating device of the slave station time device is about two orders of magnitude lower than the time generated by the master station time device, it is reliable for a short period of time. That is, since the time required to shift by one clock is approximately 10, a time signal with sufficiently high accuracy is generated for about half a day.

Next, when re-operating master station time device A, master station time device A
At the same time as the power is turned on, the master station time device A changes to the slave station time device B.
1 to Bn, the modem 2 demodulates the time code of the slave time device, and the comparator 3 compares the time signals of the slave time devices B1 to Bn by majority vote to determine the most probable time. and drives the time generator.

By using the tree method in this way, it becomes possible to freely stop and restart the operation of the main station time device without impairing the reliability of the entire time control system. That is, when the main station time device is put into operation again, it is possible to easily and accurately calibrate the time without requiring either a backup time generator or an external standard signal, which were conventionally required.

Furthermore, since only one time generating device is required for the master station time device, the equipment cost of the master station time device can be reduced, and floor space and power consumption can be reduced.

The present invention may be modified as follows.

That is, if we pay attention to the fact that in the above embodiment, the master station time device and the slave time device have the same functional configuration except for the comparator, the function of the comparator of the slave station time device is the same as the function of the comparator of the master station time device. By making them the same, the master station time device and the slave station time device have the same functional configuration. By making some of the slave station time devices have the same functional configuration as the master station time device, multiple master station time devices are provided, but the comparator function can be easily changed by changing the rough 1~ware. The reliability of the system can be further improved without requiring changes, increasing equipment costs, floor space, and power consumption.

The present invention may also be modified as follows.

That is, instead of connecting the master station time device and the slave station time device with a transmission line, wireless may be used.

FIG. 2 is a block diagram showing a modified embodiment of the present invention, in which signals are transmitted and received wirelessly between a master station and a slave station. In this example, a transceiver is used instead of a modem, and an antenna is used instead of a transmission line, but the operation is similar to that of the previous embodiment.

(Effects of the Invention) As explained above, the time control system of the present invention is a time control system using a slave synchronization method. monitor all, determine a probable time based on the time signal, and use the time information to easily correct the time signal issued by the main station time device without referring to external standard time, or Since the time signal of the master station time device is configured to be set in synchronization with the time signal of the slave station time device, the master station time device can be freely stopped and restarted without compromising the reliability of the entire system. In addition, since only one time generating device is required for the main station time device, the equipment cost of the main station time device can be reduced, and there is a significant effect in reducing floor space and power consumption.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a block diagram showing a modified embodiment of the present invention, and FIG. 3 is a block diagram of a conventional slave synchronization type time control system. A...--Main station time device Bl, B2.・・B
n -..., slave station time device 1, 5...
Time generator 2.6...Modem 3,7.
・-- Comparator 4.8...- Selector switch 9... Transmission line 1.0.11...
... Transmitter/receiver 12] 3... Antenna patent applicant Toyo Tsushinki Co., Ltd. Layer Anno Diagram

Claims (2)

[Claims] (1) In a slave synchronization type time control system in which a time signal is transmitted from a master station time device to a plurality of slave time devices, and the slave time devices generate time in synchronization with the time signal from the master station time device, If necessary, the master station time device monitors some or all of the time signals generated by the slave station time device, determines a probable time based on the time signal, and uses the time information to determine the main station time signal. A time control system characterized in that a time signal emitted by a station time device is corrected or a time signal of a master station time device is set in synchronization with a time signal of the slave station time device. (2) The time control system according to claim 1, wherein a probable time is determined by majority comparison, simple averaging, or weighted averaging of the time signals monitored by the main station time device.