High-precision timing system equipment based on rubidium clock and constant-temperature crystal oscillator

Abstract

The invention provides high-precision timing equipment based on a rubidium clock and a constant-temperature crystal oscillator, and belongs to the technical field of time-frequency synchronization. The system comprises a main control card, a monitoring card, a time code output branching card, a frequency scale output branching card, a Beidou receiver card, a 1553B bus interface card, an NTP and a PTP time service card which are installed on a VPX backboard. The time code output shunt card supports output of various time service signals, the frequency scale output shunt card supports output of various frequency scale signals, and the 1553B bus interface card can convert the time service signals of a serial port protocol into time service signals of a 1553B bus form suitable for the fields of avionics systems and the like; the NTP time service card and the PTP time service card are provided with optical fiber communication interfaces and Ethernet communication interfaces at the same time, and optical time service and electric time service can be achieved. According to the invention, a mode of'rubidium clock + crystal oscillator 'is adopted to realize time-frequency signal output, and a series clock taming mode is adopted, so that the problem that signals with high time-keeping precision and high-index frequency cannot be met at the same time in the prior art is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of time-frequency synchronization, in particular to a high-precision time system device based on rubidium clock and oven-controlled crystal oscillator. BACKGROUND

[0002] In today's highly interconnected and automated technological environment, accurate and unified time reference has become the cornerstone of the efficient and reliable operation of many key systems. Time unification device (or time synchronization system, time unification device) is a key infrastructure born to meet this core demand. Its technical necessity stems from the nature of distributed system collaboration. When multiple independent devices (such as server clusters, communication base stations, industrial controllers, sensor networks, data center nodes, or financial transaction systems) need to collaborate to handle transactions, record event sequences, or perform precise control, millisecond, microsecond, or even nanosecond time deviations can lead to data inconsistency, logical errors, control failures, or low efficiency. Time unification device establishes a high-precision time reference that all systems follow, ensuring that all nodes generate event timestamps with comparability and consistency, providing a reliable basis for fault diagnosis, transaction sequencing, and process synchronization.

[0003] In the field of time and frequency, time signals and frequency signals are mostly needed at the same time, while existing time unification devices often only use one of rubidium clock or oven-controlled crystal oscillator as the frequency source of the time unification device. Rubidium clock has better frequency stability than crystal oscillator, and crystal oscillator has better phase noise of the output frequency signal than rubidium clock, so it cannot meet the requirements of high time keeping accuracy and high index frequency signal at the same time. SUMMARY

[0004] Therefore, the present application proposes a high-precision time unification device based on rubidium clock and oven-controlled crystal oscillator. The present application adopts a "rubidium clock + oven-controlled crystal oscillator" mode, which can solve the problem of not being able to meet the requirements of high time keeping accuracy and high index frequency signal at the same time. The present application adopts a standard VPX plug-in card design, which solves the problem of inconvenient disassembly and maintenance of current time unification devices.

[0005] To achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0006] A high-precision time unification device based on rubidium clock and oven-controlled crystal oscillator, comprising a VPX backplane, the VPX backplane is inserted with a master control card, a monitoring card, a time code output branch card, a frequency standard output branch card, a Beidou receiver card, a 1553B bus interface card, an NTP and PTP time service card, wherein:

[0007] The master control card is used for receiving external reference time service signals and rubidium clock frequency signals, and outputting time signals, frequency signals and state information;

[0008] The monitoring card is used for receiving state information of each board card;

[0009] The time code output branch card is used for receiving the time signal output by the master card and branching and outputting multiple time signals;

[0010] The frequency standard output branch card is used for receiving the frequency signal output by the master card, performing phase locking and branching, and outputting multiple frequency standard signals;

[0011] The Beidou receiver card is used for receiving the Beidou satellite signal and outputting the 1PPS+ToD time signal to the master card;

[0012] The 1553B bus interface card is used for receiving the ToD time signal output by the master card and outputting the ToD time signal through the 1553B bus interface;

[0013] The NTP and PTP time card is used for receiving the 1PPS+ToD time signal output by the master card and outputting the NTP time signal and the PTP time signal.

[0014] Further, a constant temperature crystal oscillator is installed on the master card, the master card receives the external reference time signal and the 1PPS+ToD time signal output by the Beidou receiver card as the reference time source, takes the 10MHz of the constant temperature crystal oscillator as the frequency source, and generates the local 1PPS+ToD time signal based on the frequency, and outputs the local 1PPS+ToD time signal after synchronization with the reference time source.

[0015] Further, the master card outputs the time and frequency signals in a serial clock taming mode, and the specific mode is as follows:

[0016] When the external reference time signal is input, the timekeeping phase is entered;

[0017] When the external reference time signal is invalid, the timekeeping phase is entered;

[0018] In the timekeeping phase, the local time is synchronized according to the external reference time signal, the rubidium clock is used as the reference frequency source of the constant temperature crystal oscillator, the frequency of the constant temperature crystal oscillator is calibrated, and the frequency adjustment amount of the rubidium clock is saved as historical clock adjustment data;

[0019] In the timekeeping phase, the historical clock adjustment data is fitted by the least square method, the frequency adjustment amount of the rubidium clock at the next time is calculated, and the clock of the rubidium clock is compensated periodically;

[0020] In the timekeeping phase or the timekeeping phase, the rubidium clock is used as the reference frequency source of the constant temperature crystal oscillator, and the constant temperature crystal oscillator is tamed and calibrated;

[0021] The master card generates the local high-precision time signal based on the 10MHz of the constant temperature crystal oscillator, and generates the frequency standard signals of 10Mhz, 20MHz, 50MHz and 100MHz based on the 10MHz of the constant temperature crystal oscillator.

[0022] Further, the monitoring card obtains the state monitoring information of each board card through the information transmission interface, displays the state monitoring information through the display screen, and controls the on-off of the corresponding state indicator according to the state monitoring information, in addition, the interface switching, selection, cancellation and page turning of the display screen are controlled through the control signal transmitted by the receiving key.

[0023] Further, the time code output branching card receives different types of time signal output by the master control card, processes the signal, branches the time signal of each type by using a driving circuit, and outputs after increasing the driving capacity, so as to expand the time interface; the different types of time signal include 1PPS+ToD time signal, B(DC) time signal.

[0024] Further, the frequency standard output branching card receives the 10MHz frequency signal of the constant temperature crystal oscillator output by the master control card, and uses the signal as a frequency source to generate 10MHz, 20MHz, 50MHz and 100MHz frequency standard signals by using a phase-locked loop.

[0025] Further, the 1553B bus interface card receives the ToD time signal output by the master control card through the serial port, converts the serial port signal into the 1553B bus interface signal, and outputs the ToD time signal to the outside through the 1553B bus interface.

[0026] Further, the NTP and PTP time signal card is provided with a fiber communication interface and an Ethernet communication interface, and realizes fiber time signal and Ethernet time signal.

[0027] The beneficial effects of the present application compared with the prior art are:

[0028] 1. The high-precision time system equipment adopts the mode of "rubidium clock + constant temperature crystal oscillator", fully utilizes the characteristics that the frequency stability index of the rubidium clock is better than that of the crystal oscillator, and the phase noise index of the frequency signal output by the crystal oscillator is better than that of the rubidium clock, and can meet the requirements of high time keeping accuracy and high index frequency signal at the same time.

[0029] 2. The high-precision time system equipment adopts the "series clock taming" mode suitable for the mode of "rubidium clock + constant temperature crystal oscillator", which can ensure the high accuracy of the output time signal and the high index performance of the frequency signal of the equipment in the whole running period, and can also ensure the continuity of the signal.

[0030] 3. The high-precision time system equipment is built-in with a Beidou receiver, which can receive Beidou satellite signals of multiple frequency points, and can meet the requirements of external reference time signal and Beidou time signal at the same time.

[0031] 4. The high-precision time system equipment is built-in with a 1553B bus interface card, which can be applied to an avionics system, and has the characteristics of high reliability and strong real-time performance.

[0032] 5. The high-precision timing device of this invention adopts a standard VPX plug-in card design, which allows for flexible disassembly and facilitates later maintenance. Each functional board can be disassembled individually without affecting the normal use of other boards. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of a high-precision timing device based on a rubidium clock and a thermostatic crystal oscillator, according to an embodiment of the present invention.

[0034] Figure 2 This is a schematic diagram illustrating the principle of "serial clock discipline" used in a high-precision timekeeping device based on a rubidium clock and a thermostatic crystal oscillator, as described in an embodiment of the present invention.

[0035] Figure 3 This is a flowchart illustrating the "serial clock discipline" process used in a high-precision timekeeping device based on a rubidium clock and a thermostatic crystal oscillator, as described in an embodiment of the present invention. Detailed Implementation

[0036] To enable those skilled in the art to better understand the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort should fall within the scope of protection of the present invention.

[0037] A high-precision timekeeping device based on a rubidium clock and a thermostatic crystal oscillator, such as Figure 1 As shown, the device adopts a standard VPX plug-in card design, including a main control card, a monitoring card, a time code output splitter card, a frequency standard output splitter card, a Beidou receiver card, a 1553B bus interface card, NTP and PTP timing cards, a Beidou antenna, a rubidium clock, and a backplane. The temperature-controlled crystal oscillator is installed on the main control card, and the NTP and PTP timing cards have fiber optic communication and Ethernet communication interfaces.

[0038] In this device, the main control card is connected to the backplane and is used to receive external reference signals and rubidium clock frequency signals, and output time signals, frequency signals and status information.

[0039] The monitoring card is connected to the backplane and is used to receive status information from each board.

[0040] The time code output splitter card is connected to the backplane and is used to receive the time signal output by the main control card and output multiple time signals.

[0041] The frequency standard output splitter card is connected to the backplane and is used to receive the frequency signal output by the main control card. It can output multiple frequency standard signals through phase-locked loop.

[0042] The Beidou receiver card is connected to the backplane and is used to receive Beidou satellite signals and output 1PPS+ToD timing signals to the main control card.

[0043] 1553B bus interface card is connected with the backplane, used for receiving the ToD timing signal output by the master card, and outputting the ToD timing signal through the 1553B bus interface;

[0044] NTP and PTP timing card is connected with the backplane, used for receiving the 1PPS+ToD timing signal output by the master card, and outputting the NTP timing signal and the PTP timing signal.

[0045] The device has multiple high-precision timing signal interfaces and high-index frequency signal interfaces, and can meet most application scenarios in the time and frequency field.

[0046] Specifically, the master card is mainly responsible for receiving an external reference timing signal or a 1PPS+ToD timing signal output by a Beidou receiver card to complete local time synchronization and rubidium clock frequency calibration functions. When the reference timing signal or the 1PPS+ToD timing signal of the Beidou receiver fails, the master card gives up tracking the reference timing signal, enters a timekeeping state, and periodically adjusts the phase and frequency of its own time system according to historical clock adjustment data to compensate for the accumulated time deviation of the rubidium clock due to long-term operation, thereby realizing long-term time precision maintenance capability without reference timing signal.

[0047] The master card adopts a "series clock taming method". In the timing state, the rubidium clock is tamed and calibrated according to the external reference timing signal. In the timing or timekeeping state, the rubidium clock is used as an external reference for the oven-controlled crystal oscillator. The 1PPS signal is generated by using the rubidium clock as a frequency source to tame and calibrate the oven-controlled crystal oscillator, thereby maintaining the continuous accuracy and stability of the frequency accuracy of the oven-controlled crystal oscillator. The rubidium clock is used as a frequency source to generate high-precision timing signals, and the 10MHz frequency signal output by the oven-controlled crystal oscillator is used as the frequency source of the frequency standard output branching card to generate high-index 10Mhz, 20MHz, 50MHz and 100MHz frequency standard signals.

[0048] The monitoring card is a board card responsible for state monitoring in a high-precision time system device. It obtains state monitoring information of each board card through various information transmission interfaces. After obtaining the state monitoring information of all board cards, the monitoring card displays the state information through a control display screen, and controls the interface switching, selection, cancellation and page turning of the display screen by receiving control signals transmitted by the keys. The monitoring card controls the on / off of the corresponding state indicator light according to the obtained state monitoring information to achieve the prompting effect.

[0049] The time code output branching card receives different types of timing signals output by the master card, processes the signals, and outputs the signals after branching and increasing the driving capability by using driving circuits and other means, so as to achieve the effect of expanding the timing interface.

[0050] The frequency standard output branch card receives the 10MHz frequency signal of the constant temperature crystal oscillator output by the master card, and uses the signal as a frequency source to generate 10MHz, 20MHz, 50MHz and 100MHz frequency standard signals by using the technology of phase-locked loop, and in addition, the various frequency standard signals are all output in four ways through the shunt technology, for use by other devices.

[0051] The Beidou receiver card receives the Beidou satellite signal through the TNC connector of the rear panel of the case, generates a 1PPS+ToD time signal and outputs the signal to the master card, and realizes Beidou time service.

[0052] The 1553B bus interface card realizes the conversion of a serial port into a 1553B bus interface, receives the ToD time signal output by the master card through the serial port, and outputs the ToD time signal to the outside through the 1553B bus interface, and can be applied to an avionics system, and has the characteristics of high reliability and strong real-time performance.

[0053] The NTP and PTP time service card receives the 1PPS+ToD time signal output by the master card and converts the signal into a time service signal of the NTP protocol and the PTP protocol, the NTP and PTP time service card has a fiber communication interface and an Ethernet communication interface, realizes fiber time service and Ethernet time service, and meets the requirements of different scenes.

[0054] The master card adopts a "series clock taming" mode to output time and frequency signals. Specifically, the master card receives an external reference time signal and a 1PPS+ToD time signal output by the Beidou receiver card as a reference time source, takes the 10MHz of the rubidium clock as a frequency source, and generates a local 1PPS+ToD time signal and other time signals based on the frequency reference, and then outputs the signals after synchronization with the reference time source. During the time service stage, the master card measures the time difference between the rubidium clock and the external reference time signal, and obtains the frequency adjustment information of the rubidium clock after digital filtering and clock taming calculation, so as to control the rubidium clock to realize frequency calibration and local time synchronization. After the external reference time signal fails, the master card compensates the rubidium clock according to the historical taming data, so as to achieve higher accuracy of time keeping and ensure high-precision time service. During the time service stage or the time keeping stage, the rubidium clock is taken as a reference frequency source of the oven-controlled crystal oscillator, so as to realize taming calibration of the oven-controlled crystal oscillator. The monitoring card is a monitoring center of the entire device, and realizes state monitoring of all modules of the entire device through various interactive modes. The monitoring card controls the liquid crystal display, the response of the key instruction, and the display of the state indicating lamp. The time code output branching card receives the 1PPS+ToD time signal and the B(DC) time signal output by the master card, processes the signals, and outputs the 1PPS+ToD time signal and the B(DC) time signal after branching and increasing the driving capacity, so as to achieve the effect of expanding the time service interface. The frequency standard output branching card receives the 10MHz frequency signal of the oven-controlled crystal oscillator output by the master card, takes the signal as a frequency source, and generates 10MHz, 20MHz, 50MHz and 100MHz frequency standard signals by using a phase-locked loop technology. The Beidou receiver card receives the Beidou satellite signal, generates a 1PPS+ToD time signal, and outputs the signal to the master card. The 1553B bus interface card receives the ToD time signal output by the master card through a serial port, converts the serial port into a 1553B bus communication interface, and outputs the ToD time signal to the outside. The NTP and PTP time service card receives the 1PPS+ToD time signal output by the master card and converts the signal into an NTP and PTP time signal, so as to realize NTP time service and PTP time service.

[0055] Figure 2 The series clock taming mode of the high-precision time service device during the time service stage and the time keeping stage is shown. Figure 3The specific process of series clock taming is shown. After the high-precision time system device is started, it waits for the input of external reference time signal. After receiving the external reference time signal, it enters the time service stage, synchronizes the local time and calibrates the rubidium clock frequency according to the external reference time signal, and uses the rubidium clock as the reference frequency source of the oven-controlled crystal oscillator to realize the frequency calibration of the oven-controlled crystal oscillator. The time system device continuously detects the input of the external reference time signal until the external reference time signal is invalid (such as disconnecting the external reference time signal input), and the time system device enters the time keeping stage. In the time keeping stage, the rubidium clock is compensated according to the historical clock adjustment data to realize high-precision time keeping. In both the time service stage and the time keeping stage, the rubidium clock is used as the external reference of the oven-controlled crystal oscillator to tame and calibrate the oven-controlled crystal oscillator. The 10MHz of the rubidium clock is used as the reference to generate the local high-precision time service signal, and the 10MHz of the oven-controlled crystal oscillator is used as the reference to generate the high-index frequency signal such as 10Mhz, 20MHz, 50MHz and 100MHz.

[0056] In the application, the time code output branch card supports output of various time service signals, the frequency standard output branch card supports output of various frequency standard signals, the 1553B bus interface card can convert the time service signal of serial port protocol into the time service signal of 1553B bus suitable for the field of avionics system, and the NTP and PTP time service card has optical fiber communication interface and Ethernet communication interface, and can realize optical time service and electrical time service.

[0057] The application adopts the mode of "rubidium clock + crystal oscillator" to realize time and frequency signal output, and adopts series clock taming mode, and solves the problem that high time keeping accuracy and high-index frequency signal cannot be simultaneously met at present.

[0058] In summary, the application adopts standard VPX plug-in card design, solves the problem of inconvenient disassembly and maintenance of complex time system device board card, can output various time service signals and frequency standard signals, supports optical fiber, Ethernet, 1553B and differential RS422 time service, and can meet the needs of most application scenarios in the time and frequency field.

Claims

1. A high-precision time system device based on a rubidium clock and a constant temperature crystal oscillator, characterized in that, The application relates to a VPX backplane, wherein a master card, a monitoring card, a time code output branch card, a frequency standard output branch card, a Beidou receiver card, a 1553B bus interface card and an NTP and PTP timing card are inserted on the VPX backplane. The master card is used for receiving external reference timing signals and rubidium clock frequency signals, and outputs time signals, frequency signals and state information. The monitoring card is used for receiving state information of each board card. The time code output branch card is used for receiving time signals output by the master card and branching and outputting multiple time signals. The frequency standard output branch card is used for receiving frequency signals output by the master card, carrying out phase locking and branching and outputting multiple frequency standard signals. The Beidou receiver card is used for receiving Beidou satellite signals and outputting 1PPS+ToD timing signals to the master card. The 1553B bus interface card is used for receiving ToD timing signals output by the master card and outputting the ToD timing signals through a 1553B bus interface. The NTP and PTP timing card is used for receiving 1PPS+ToD timing signals output by the master card and outputting NTP timing signals and PTP timing signals.

2. The high-precision time system device based on rubidium clock and constant temperature crystal oscillator according to claim 1, characterized in that, The master card is provided with a constant temperature crystal oscillator, and the master card receives external reference timing signals and 1PPS+ToD timing signals output by the Beidou receiver card as reference time sources, takes the 10MHz of the constant temperature crystal oscillator as a frequency source, generates local 1PPS+ToD timing signals based on the frequency, and outputs the local 1PPS+ToD timing signals after synchronization with the reference time sources.

3. The high-precision time system device based on rubidium clock and constant temperature crystal oscillator according to claim 1, characterized in that, The master card adopts a series clock taming mode to output time and frequency signals, and the specific mode is as follows: When external reference timing signals are input, the master card enters a timing stage; When the external reference timing signals are invalid, the master card enters a time keeping stage; In the timing stage, the master card synchronizes local time based on the external reference timing signals and calibrates the frequency of the rubidium clock, simultaneously takes the rubidium clock as a reference frequency source of the constant temperature crystal oscillator, and realizes frequency calibration of the constant temperature crystal oscillator; In addition, the master card saves the frequency adjustment amount of the rubidium clock as historical clock adjustment data; In the time keeping stage, the master card fits the historical clock adjustment data through a least square method, calculates the frequency adjustment amount of the rubidium clock at the next time, and periodically compensates the clock of the rubidium clock; In both the timing stage and the time keeping stage, the master card takes the rubidium clock as a reference frequency source of the constant temperature crystal oscillator and tames and calibrates the constant temperature crystal oscillator; The master card generates local high-precision timing signals based on the 10MHz of the constant temperature crystal oscillator, and generates 10Mhz, 20MHz, 50MHz and 100MHz frequency standard signals based on the 10MHz of the constant temperature crystal oscillator.

4. The high-precision time system device based on rubidium clock and constant temperature crystal oscillator according to claim 1, characterized in that, The monitoring card obtains state monitoring information of each board card through an information transmission interface, displays the state monitoring information through a display screen, controls the on-off of corresponding state indicator lights according to the state monitoring information, and further controls the interface switching, selection, cancellation and page turning of the display screen through the control signals transmitted by the keys.

5. The high-precision time system device based on rubidium clock and constant temperature crystal oscillator according to claim 1, characterized in that, The time code output branch card receives different types of timing signals output by the master card, processes the signals, branches the timing signals through a driving circuit, increases the driving capacity and then outputs, so as to expand the timing interface; the different types of timing signals include 1PPS+ToD timing signals and B(DC) timing signals.

6. The high-precision time system device based on rubidium clock and constant temperature crystal oscillator according to claim 1, characterized in that, The frequency standard output branch card receives the 10MHz frequency signal of the constant temperature crystal oscillator output by the master card, and uses the signal as a frequency source to generate 10MHz, 20MHz, 50MHz and 100MHz frequency standard signals by using a phase-locked loop.

7. The high-precision time system device based on rubidium clock and constant temperature crystal oscillator according to claim 1, characterized in that, The 1553B bus interface card receives the ToD time signal output by the master card through a serial port, converts the serial port signal into a 1553B bus interface signal, and outputs the ToD time signal to the outside through the 1553B bus interface.

8. The high-precision time system device based on rubidium clock and constant temperature crystal oscillator according to claim 1, characterized in that, The NTP and PTP time service card is provided with a fiber communication interface and an Ethernet communication interface, and realizes fiber time service and Ethernet time service.

Images