System for generating multiple types of coherent time-frequency signals

Abstract

The invention relates to a system for generating multiple types of coherent time-frequency signals. The system comprises an offset frequency generation module and a multi-source frequency and time generation module, the offset frequency generation module generates coherent time-frequency signals with different frequencies based on the same reference source according to the constellation synchronization requirement of the satellite time-frequency system; the time generation and measurement module generates time frequency signals used by various satellite loads in a frequency division or frequency multiplication mode according to the coherent time frequency signals generated by the offset frequency generation module, generates 1pps signals for the various time frequency signals respectively, measures the phase difference of the 1pps generated by the multi-source coherent time frequency signals, obtains the phase difference of multiple time frequency references and outputs the phase difference. According to the invention, various time-frequency signals required by the satellite load can be generated, the time-frequency signals are coherent, the 1pps phase difference generated by the time-frequency signals is fixed and measurable, and technical support is provided for the satellite load to support measurement of various signal systems.

Description

Technical Field

[0001] The invention belongs to the field of time and frequency, and relates to a system for generating multiple types of coherent time and frequency signals. Background Art

[0002] With the development of high integration of satellite payloads, the time-frequency system needs to provide a variety of coherent time-frequency signals to provide a basis for other payloads to carry out measurements and communications of different signal systems. In the field of deep space measurement, satellite payloads support multi-mode working systems. Satellite payloads need to use the same time-space reference to generate different time-frequency signals, and the measurement results using different time-frequency signals need to be consistent.

[0003] For satellite systems compatible with multiple signal systems, based on the 10MHz input, the time-frequency system needs to provide other payloads with two time-frequency signals, 100MHz and 102.3MHz, and a 1pps signal. At the same time, based on the inter-satellite measurement results, it has the ability to adjust the frequency to meet the constellation time generation and maintenance functions. Compared with the previous design of the time-frequency reference generation and maintenance unit, this application scenario needs to provide two coherent time-frequency signals, and 100MHz, 102.3MHz and 1pps need to have a definite and quantitative phase relationship to meet the needs of precision measurement.

[0004] In the past, a single time-frequency signal could meet the design requirements in satellite time-frequency systems. In response to the use requirements of multiple time-frequency signals, it is necessary to design a system that generates multiple types of coherent time-frequency signals, generate coherent time-frequency signals of different frequencies, provide a frequency reference source for the satellite's multiple mode precision measurements, and use time-frequency signals of different frequencies according to the requirements of the precision measurement system. Summary of the invention

[0005] The technical problem solved by the present invention is: to overcome the shortcomings of the prior art and propose a system for generating multiple types of coherent time-frequency signals, to generate time-frequency signals required by multiple satellite payloads, wherein each time-frequency signal is coherent and each time-frequency signal generates a fixed and measurable 1pps phase difference, thereby providing technical support for satellite payloads to support the measurement of multiple signal systems.

[0006] The solution of the present invention is:

[0007] A system for generating multiple types of coherent time-frequency signals, including an offset frequency generation module, a multi-source frequency and time generation module;

[0008] Offset frequency generation module: generates coherent time-frequency signals of different frequencies based on the same reference source according to the requirements of satellite time-frequency system constellation synchronization;

[0009] Time generation and measurement module: Based on the coherent time-frequency signals generated by the offset frequency generation module, time-frequency signals used by various satellite payloads are generated by frequency division or multiplication. 1pps signals are generated for various time-frequency signals respectively, and the phase difference of 1pps generated by multi-source coherent time-frequency signals is measured to obtain the phase difference of multiple time-frequency references and output them.

[0010] Preferably, the offset frequency generation module includes a control management module, a main mixer, a standby mixer, a phase meter, a selection switch, a main two-power divider, a standby two-power divider and a first phase-locked loop;

[0011] Control management module: Generate the offset frequency X1 Hz of the multi-source frequency signal according to the 10 MHz time-frequency signal input from the main channel and the 10 MHz time-frequency signal input from the backup channel; receive frequency adjustment data according to the requirements of the satellite time-frequency system constellation synchronization, and use the time scale algorithm to generate the constellation integrated atomic time paper time, which adjusts the offset frequency X1 Hz, and obtains the main channel offset frequency X1 Hz signal and the backup channel offset frequency X1 Hz signal after adjustment;

[0012] The 10 MHz time-frequency signal inputted by the main path and the signal of the main path offset frequency X1 Hz are mixed in the main path mixer to generate a signal of the main path frequency X2 Hz; the 10 MHz time-frequency signal inputted by the backup path and the signal of the backup path offset frequency X1 Hz are mixed in the backup path mixer to generate a signal of the backup path frequency X2 Hz;

[0013] The signal of the main circuit frequency X2Hz is divided into two paths through the main circuit two-power divider, one path enters the phase meter, and the other path enters the selection switch; the signal of the backup circuit frequency X2Hz is divided into two paths through the backup circuit two-power divider, one path enters the phase meter, and the other path enters the selection switch;

[0014] The phase meter measures the signal frequencies from the two power dividers of the main circuit and the two power dividers of the backup circuit respectively, determines whether there is a fault and the fault mode when there is a fault according to the multiple sets of clock difference data obtained, and sends a disposal strategy to the selection switch according to the judgment result;

[0015] The selection switch selects to output a signal of a main path frequency of X2 Hz or a signal of a backup path frequency of X2 Hz or a signal after weighting the main and backup path frequencies to the first phase-locked loop according to the disposal strategy;

[0016] The first phase-locked loop purifies the input signal and outputs a signal with a frequency of X3 Hz to the source frequency and time generation module.

[0017] Preferably, the control management module generates an offset frequency X1 Hz of the multi-source frequency signal through DDS.

[0018] Preferably, the phase meter has the functions of dynamically accessing, removing and adjusting the weight of the atomic clock, so as to ensure that the failure of a single atomic clock does not affect the timekeeping function and performance of the system.

[0019] Preferably,

[0020] If the phase meter determines that there is no fault, the handling strategy sent to the selection switch is to select the main signal;

[0021] If the phase meter determines that there is a fault in the main line, the handling strategy sent to the selector switch is to select the backup line signal, and at the same time generate a main line fault mode type telemetry signal to transmit to the ground, providing a basis for the ground measurement and control personnel to carry out subsequent handling;

[0022] If the phase meter determines that there is a fault in the backup line, the handling strategy sent to the selection switch is to select the main line signal, and at the same time generate a backup line fault mode type telemetry signal to transmit to the ground, providing a basis for the ground measurement and control personnel to carry out subsequent handling;

[0023] If the phase meter determines that there is a fault in the main and backup lines, a high-priority fault mode telemetry signal is generated. After the telemetry signal is transmitted to the ground, the ground measurement and control personnel are required to take immediate measures to quickly restore the normal operation of the time and frequency signal system.

[0024] Preferably, the multi-source frequency and time generation module includes a three-power divider, a time generation and measurement module, a X4 Hz frequency generation module, and a X5 Hz frequency generation module;

[0025] The three-way power divider divides the signal from the offset frequency generation module into three paths, which are input into the X4 Hz frequency generation module, the X5 Hz frequency generation module, and the time generation and measurement module respectively;

[0026] The X4 Hz frequency generation module includes a first frequency divider and a second phase-locked loop, the first frequency divider determines a frequency division coefficient according to the frequency X3 Hz and the frequency X4 Hz, divides the frequency signal of the frequency X3 Hz from the offset frequency generation module according to the frequency division coefficient, and sends the divided signal to the second phase-locked loop for purification to obtain a time-frequency source of the frequency X4 Hz with low phase noise, and the time-frequency source of the frequency X4 Hz is output to the outside on the one hand, and sent to the time generation and measurement module on the other hand;

[0027] The X5Hz frequency generation module includes a second frequency divider and a third phase-locked loop, the second frequency divider determines a frequency division coefficient according to the frequency X3Hz and the frequency X5Hz, divides the frequency signal of the frequency X3Hz from the offset frequency generation module according to the frequency division coefficient, and sends the divided signal to the third phase-locked loop for purification to obtain a time-frequency source of the frequency X5Hz with low phase noise, and the time-frequency source of the frequency X5Hz is output to the outside on the one hand, and sent to the time generation and measurement module on the other hand;

[0028] The time generation and measurement module generates 1pps at a frequency of X4Hz and 1pps at a frequency of X5Hz according to the time-frequency source signals of a frequency of X4Hz and a frequency of X5Hz, and measures the phase difference between the two 1pps signals. The output 1pps at a frequency of X4Hz provides a time reference for other loads, which is recorded as the reference 1pps; and provides the phase difference of the 1pps at a frequency of X5Hz relative to the reference 1pps.

[0029] The beneficial effects of the present invention compared with the prior art are:

[0030] (1) The present invention proposes an offset frequency generation module and a multi-source frequency and time generation module system architecture. The frequency offset module has an offset frequency X1 for generating a multi-source frequency signal. The offset frequency X1 is generated by a DDS. The DDS has a frequency adjustment function. According to the requirements of the satellite time and frequency system constellation synchronization, the management and control module receives the frequency adjustment data. The design of the offset frequency generation module ensures the coherence of the multi-source time and frequency.

[0031] (2) The offset frequency generation module of the present invention adopts a main path and a backup path design, and performs mutual measurement between the main and backup X2 frequencies. A certain evaluation strategy is adopted based on the multiple sets of clock difference data obtained to determine the faulty clock, fault type and severity. Different handling strategies are formulated according to different fault modes. The frequency switching time is short, ensuring the continuity of the satellite-borne time and frequency system.

[0032] (3) The present invention designs a time generation module to measure the 1pps phase difference generated by multi-source coherent time-frequency coherent signals. According to the different time-frequency signals generated, the 1pps measurement module is used to obtain the phase difference of multiple time-frequency references. The 1pps phase relationship generated by multi-source coherent signals can be given in real time for use by different loads. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 is a system block diagram of the present invention;

[0034] Figure 2 It is a schematic diagram of an embodiment of the present invention. DETAILED DESCRIPTION

[0035] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0036] The important function of the time-frequency system is to provide the time-frequency reference for other systems, and to be responsible for the generation and maintenance of the single satellite reference time and constellation time. With the development of high integration of satellite payloads, the time-frequency system needs to provide a variety of coherent time-frequency signals to provide a basis for other payloads to carry out measurement and communication of different signal systems. The multi-source coherent time-frequency generation and maintenance system of the present invention can support the field of deep space measurement and support the system of satellite payloads carrying out multi-mode work.

[0037] The present invention provides a system for generating multiple types of coherent time-frequency signals, the system composition of which is as follows Figure 1 As shown, the system includes an offset frequency generation module and a multi-source frequency and time generation module.

[0038] Offset frequency generation module: According to the requirements of satellite time and frequency system constellation synchronization, coherent time and frequency signals of different frequencies are generated based on the same reference source. This module generates an offset frequency signal that generates multiple coherent time and frequency signals through subsequent frequency multiplication or division. The frequency of this signal is X3 Hz. According to the requirements of satellite time and frequency system constellation synchronization, the frequency adjustment data is received and the frequency of the offset frequency X3 Hz signal is adjusted, so that various types of time and frequency signals generated based on the X3 offset frequency can be synchronously adjusted to ensure the coherence of the multi-time and frequency system design.

[0039] Time generation and measurement module: This module generates time-frequency signals used by various satellite payloads by frequency division or multiplication based on the offset frequency X3Hz signal; this module generates 1pps signals according to the various time-frequency signals generated, and measures the phase difference of 1pps generated by multi-source coherent time-frequency signals, obtains the phase difference of multiple time-frequency references and outputs them.

[0040] (1) Offset frequency generation module

[0041] The module includes a main input frequency of 10MHz, a backup input of 10MHz, a mixer, a phase meter, a selection switch, a two-power divider, a control management module and a phase-locked loop.

[0042] In order to improve the reliability of the satellite-borne time and frequency system, the system is input by two main and backup time and frequency signals. The control module generates the offset frequency X1 Hz of the multi-source frequency signal based on the input time and frequency signal. The offset frequency X1 Hz is generated by DDS, which has the function of frequency adjustment. According to the requirements of the satellite time and frequency system constellation synchronization, the management and control module receives the frequency adjustment data and generates the paper time of the constellation integrated atomic time by using the time scale algorithm. The paper time adjusts the local atomic time 10MHz signal by adjusting the frequency of X1 Hz, and generates the main and backup X1 Hz. After the mixer calculates, the main frequency X2Hz signal and the backup frequency X2Hz signal are generated.

[0043] The signal of the main frequency X2Hz is divided into two paths through the main dual power divider, one path enters the phase meter and the other path enters the selection switch; the signal of the backup frequency X2Hz is divided into two paths through the backup dual power divider, one path enters the phase meter and the other path enters the selection switch.

[0044] The phase meter measures the signal frequencies from the main two-way power divider and the backup two-way power divider respectively, and determines whether there is a fault and the fault mode when a fault occurs based on the multiple sets of clock difference data obtained, and sends a disposal strategy to the selection switch based on the judgment result. The phase meter realizes precise and real-time fault monitoring and disposal of the frequency X2Hz signal, and has the functions of dynamic access, removal and weight adjustment of atomic clocks, ensuring that the failure of a single atomic clock does not affect the system's timekeeping function and performance. Through mutual testing between the main and backup frequency X2Hz signals, a certain evaluation strategy is adopted based on the multiple sets of clock difference data obtained to determine the faulty clock, fault type and severity, and different disposal strategies are formulated according to different fault modes.

[0045] The selection switch selects to output a signal of a main path frequency of X2 Hz or a signal of a backup path frequency of X2 Hz or a signal after weighting the main and backup path frequencies to the first phase-locked loop according to the disposal strategy;

[0046] The first phase-locked loop purifies the input signal and outputs a signal with a frequency of X3 Hz to the source frequency and time generation module.

[0047] If the phase meter determines that there is no fault, the handling strategy sent to the selection switch is to select the main signal;

[0048] If the phase meter determines that there is a fault in the main line, the handling strategy sent to the selector switch is to select the backup line signal, and at the same time generate a main line fault mode type telemetry signal to transmit to the ground, providing a basis for the ground measurement and control personnel to carry out subsequent handling;

[0049] If the phase meter determines that there is a fault in the backup line, the handling strategy sent to the selection switch is to select the main line signal, and at the same time generate a backup line fault mode type telemetry signal to transmit to the ground, providing a basis for the ground measurement and control personnel to carry out subsequent handling;

[0050] If the phase meter determines that there is a fault in the main and backup lines, a high-priority fault mode telemetry signal is generated. After the telemetry signal is transmitted to the ground, the ground measurement and control personnel are required to take immediate measures to quickly restore the normal operation of the time and frequency signal system.

[0051] (2) Multi-source frequency and time generation module

[0052] The multi-source frequency and time generation module includes a three-power divider, a time generation and measurement module, a X4 Hz frequency generation module, and a X5 Hz frequency generation module.

[0053] The three-way power divider divides the signal from the offset frequency generation module into three paths, which are input into the X4 Hz frequency generation module, the X5 Hz frequency generation module, and the time generation and measurement module respectively.

[0054] The X4 Hz frequency generation module includes a first frequency divider and a second phase-locked loop. The first frequency divider determines a frequency division coefficient according to the frequency X3 Hz and the frequency X4 Hz, divides the frequency signal of the frequency X3 Hz from the offset frequency generation module according to the frequency division coefficient, and sends the divided signal to the second phase-locked loop for purification to obtain a time-frequency source with a frequency of X4 Hz with low phase noise. The time-frequency source with a frequency of X4 Hz is output to the outside on the one hand, and sent to the time generation and measurement module on the other hand.

[0055] The X5Hz frequency generation module includes a second frequency divider and a third phase-locked loop, the second frequency divider determines a frequency division coefficient according to the frequency X3Hz and the frequency X5Hz, divides the frequency signal of the frequency X3Hz from the offset frequency generation module according to the frequency division coefficient, and sends the divided signal to the third phase-locked loop for purification to obtain a time-frequency source of the frequency X5Hz with low phase noise, and the time-frequency source of the frequency X5Hz is output to the outside on the one hand, and sent to the time generation and measurement module on the other hand;

[0056] The time generation and measurement module generates 1pps at a frequency of X4Hz and 1pps at a frequency of X5Hz according to the time-frequency source signals of a frequency of X4Hz and a frequency of X5Hz, and measures the phase difference between the two 1pps signals. The output 1pps at a frequency of X4Hz provides a time reference for other loads, which is recorded as the reference 1pps; and provides the phase difference of the 1pps at a frequency of X5Hz relative to the reference 1pps.

[0057] Example:

[0058] In response to the use requirements of generating multiple signals, based on the 10MHz input, the time-frequency signal system needs to provide two time-frequency signals of 100MHz and 102.3MHz and a 1pps signal for other payloads. At the same time, based on the inter-satellite measurement results, it has the ability to adjust the frequency to meet the constellation time generation and maintenance functions.

[0059] like Figure 2 As shown, the control management module generates an offset frequency of 230KHz for the multi-source frequency signal. The offset frequency 230KHz is generated by DDS. The DDS has a frequency adjustment function. According to the requirements of the satellite time and frequency system constellation synchronization, the management control module receives the frequency adjustment data and generates the constellation integrated atomic time paper time using the time scale algorithm. The paper time adjusts the local atomic time 10MHz signal by adjusting the frequency of 230KHz, and adjusts the main and backup paths to generate 230KHz. After calculation by the mixer, the main path frequency of 10.23MHz and the backup path frequency of 10.23MHz are generated.

[0060] The multi-source frequency and time generation module includes a 102.3MHz frequency generation module and a 100MHz frequency generation module. The divider coefficient used by the 102.3M frequency generation module is 1, and the frequency of the phase-locked loop VCO is 102.3MHz. After phase locking, it directly outputs 102.3MHz.

[0061] The frequency divider coefficient used by the 102.3M frequency generation module is 1, and the frequency of the phase-locked loop VCO is 1023MHz. The phase-locked loop generates a 102.3M frequency after dividing by 10. Then, a frequency divider with a division coefficient of 1023 and a 100MHz VCO are used to directly output 100MHz after phase locking.

[0062] Using the various types of coherent time-frequency signal systems introduced above, 10 MHz is used as the input time-frequency source to generate 102.3 MHz signals and 100 MHz signals. The indicators of the generated signals are shown in Table 1. This indicator can meet the measurement and communication requirements of satellite payloads with different signal systems.

[0063] Table 1 Indicators of generated signals

[0064]

[0065]

[0066] The present invention proposes a multi-source coherent time-frequency signal system. Compared with the previous single time-frequency generation and maintenance system, an offset frequency generation module and a multi-source frequency and time generation module system architecture are designed. The frequency offset module has an offset frequency X1 Hz for generating a multi-source frequency signal. The offset frequency X1 Hz is generated by a DDS. The DDS has a frequency adjustment function. According to the requirements of the satellite time-frequency system constellation synchronization, the management control module receives the frequency adjustment data. The design of the offset frequency module ensures the coherence of the multi-source time-frequency. The single time-frequency generation unit does not have a phase measurement function. In order to determine the phase difference of 1 pps generated by each time-frequency source, the present invention designs a time generation and measurement module to measure the phase difference of 1 pps generated by the multi-source coherent time-frequency coherent signal. According to the generation of different time-frequency signals, the 1 pps measurement module is used to obtain the phase difference of multiple time-frequency references. This design enables the satellite payload to support a multi-mode working system, and the satellite payload can use the same time and space reference when using different modes.

[0067] The contents not described in detail in the specification of the present invention belong to the common knowledge of those skilled in the art.

Claims

1. A system for generating multiple types of coherent time-frequency signals, characterized in that: It includes an offset frequency generation module and a multi-source frequency and time generation module; Offset frequency generation module: generates coherent time-frequency signals of different frequencies based on the same reference source according to the requirements of satellite time-frequency system constellation synchronization; Time generation and measurement module: Based on the coherent time-frequency signals generated by the offset frequency generation module, time-frequency signals used by various satellite payloads are generated by frequency division or multiplication. 1pps signals are generated for various time-frequency signals respectively, and the phase difference of 1pps generated by multi-source coherent time-frequency signals is measured to obtain the phase difference of multiple time-frequency references and output them.

2. A system for generating multiple types of coherent time-frequency signals according to claim 1, characterized in that: The offset frequency generation module includes a control management module, a main mixer, a standby mixer, a phase meter, a selection switch, a main two-power divider, a standby two-power divider and a first phase-locked loop; Control management module: Generate the offset frequency X1 Hz of the multi-source frequency signal according to the 10 MHz time-frequency signal input from the main channel and the 10 MHz time-frequency signal input from the backup channel; receive frequency adjustment data according to the requirements of the satellite time-frequency system constellation synchronization, and use the time scale algorithm to generate the constellation integrated atomic time paper time, which adjusts the offset frequency X1 Hz, and obtains the main channel offset frequency X1 Hz signal and the backup channel offset frequency X1 Hz signal after adjustment; The 10 MHz time-frequency signal inputted by the main path and the signal of the main path offset frequency X1 Hz are mixed in the main path mixer to generate a signal of the main path frequency X2 Hz; the 10 MHz time-frequency signal inputted by the backup path and the signal of the backup path offset frequency X1 Hz are mixed in the backup path mixer to generate a signal of the backup path frequency X2 Hz; The signal of the main circuit frequency X2Hz is divided into two paths through the main circuit two-power divider, one path enters the phase meter, and the other path enters the selection switch; the signal of the backup circuit frequency X2Hz is divided into two paths through the backup circuit two-power divider, one path enters the phase meter, and the other path enters the selection switch; The phase meter measures the signal frequencies from the two power dividers of the main circuit and the two power dividers of the backup circuit respectively, determines whether there is a fault and the fault mode when there is a fault according to the multiple sets of clock difference data obtained, and sends a disposal strategy to the selection switch according to the judgment result; The selection switch selects to output a signal of a main path frequency of X2 Hz or a signal of a backup path frequency of X2 Hz or a signal after weighting the main path and backup path frequencies to the first phase-locked loop according to the disposal strategy; The first phase-locked loop purifies the input signal and outputs a signal with a frequency of X3 Hz to the source frequency and time generation module.

3. The system for generating multiple types of coherent time-frequency signals according to claim 2, characterized in that: The control management module generates the offset frequency X1 Hz of the multi-source frequency signal through DDS.

4. The system for generating multiple types of coherent time-frequency signals according to claim 2, characterized in that: The phase meter has the functions of dynamic access, removal and weight adjustment of atomic clocks, ensuring that the failure of a single atomic clock does not affect the system's timekeeping function and performance.

5. The system for generating multiple types of coherent time-frequency signals according to claim 2, characterized in that: If the phase meter determines that there is no fault, the handling strategy sent to the selection switch is to select the main line signal; If the phase meter determines that there is a fault in the main line, the handling strategy sent to the selector switch is to select the backup line signal, and at the same time generate a main line fault mode type telemetry signal to transmit to the ground, providing a basis for the ground measurement and control personnel to carry out subsequent handling; If the phase meter determines that there is a fault in the backup line, the handling strategy sent to the selection switch is to select the main line signal, and at the same time generate a backup line fault mode type telemetry signal to transmit to the ground, providing a basis for the ground measurement and control personnel to carry out subsequent handling; If the phase meter determines that there is a fault in the main and backup lines, a high-priority fault mode telemetry signal is generated. After the telemetry signal is transmitted to the ground, the ground measurement and control personnel are required to take immediate measures to quickly restore the normal operation of the time and frequency signal system.

6. The system for generating multiple types of coherent time-frequency signals according to claim 1, characterized in that: The multi-source frequency and time generation module includes a three-power divider, a time generation and measurement module, a X4 Hz frequency generation module, and a X5 Hz frequency generation module; The three-way power divider divides the signal from the offset frequency generation module into three paths, which are input into the X4 Hz frequency generation module, the X5 Hz frequency generation module, and the time generation and measurement module respectively; The X4 Hz frequency generation module includes a first frequency divider and a second phase-locked loop, the first frequency divider determines a frequency division coefficient according to the frequency X3 Hz and the frequency X4 Hz, divides the frequency signal of the frequency X3 Hz from the offset frequency generation module according to the frequency division coefficient, and sends the divided signal to the second phase-locked loop for purification to obtain a time-frequency source of the frequency X4 Hz with low phase noise, and the time-frequency source of the frequency X4 Hz is output to the outside on the one hand, and sent to the time generation and measurement module on the other hand; The X5Hz frequency generation module includes a second frequency divider and a third phase-locked loop, the second frequency divider determines a frequency division coefficient according to the frequency X3Hz and the frequency X5Hz, divides the frequency signal of the frequency X3Hz from the offset frequency generation module according to the frequency division coefficient, and sends the divided signal to the third phase-locked loop for purification to obtain a time-frequency source of the frequency X5Hz with low phase noise, and the time-frequency source of the frequency X5Hz is output to the outside on the one hand, and sent to the time generation and measurement module on the other hand; The time generation and measurement module generates 1pps at a frequency of X4Hz and 1pps at a frequency of X5Hz according to the time-frequency source signals of a frequency of X4Hz and a frequency of X5Hz, and measures the phase difference between the two 1pps signals. The output 1pps at a frequency of X4Hz provides a time reference for other loads, which is recorded as the reference 1pps; and provides the phase difference of the 1pps at a frequency of X5Hz relative to the reference 1pps.

Images