A Rubidium Atomic Clock Discipline System

Abstract

The invention discloses a rubidium atomic clock taming system, which comprises: a rubidium quantum unit, a rubidium servo circuit unit, a constant temperature crystal oscillator, a whole machine frequency adjustment unit, a main control MCU, a first frequency divider, a second frequency divider, a third frequency divider, a first time digital conversion unit, a second time digital conversion unit, a numerically controlled oscillator, a time difference processor, a digital phase-locked loop and a frequency multiplier, wherein the main control MCU is used for controlling and setting parameters of the rubidium quantum unit and working parameters of the rubidium servo circuit unit to complete frequency locking of the rubidium atomic clock; after the frequency locking of the rubidium atomic clock is completed, the frequency signal of the rubidium atomic clock is compared with the frequency signal of an external input, and the main control MCU controls the rubidium atomic clock to adjust the whole machine frequency, thereby completing the taming.

Description

Technical Field

[0001] The present invention relates to the field of atomic frequency standards and measurements, and more specifically, to a rubidium atomic clock taming system. Background Art

[0002] The rubidium atomic clock is a secondary frequency standard. During use, it often receives navigation satellite signals for timing and frequency calibration to obtain an accurate 10MHz frequency signal and a 1PPS pulse signal of time information.

[0003] Usually, the rubidium atomic clock can only accept 1PPS signal taming. It uses FPGA to design a frequency division factor of 10 7 The fixed frequency divider divides the 10MHz signal output by the rubidium atomic clock crystal into a 1PPS pulse signal, and then uses the time difference measurement unit to measure the rising edge time difference between this 1PPS signal and the external 1PPS (usually generated by the navigation receiver). By adjusting the frequency of the rubidium atomic clock, this time difference is always kept at a constant value. Because the accuracy of the 1PPS signal generated by the navigation receiver is determined by the satellite onboard clock, and the satellite onboard clock is calibrated and traced to the Coordinated Universal Time (UTC) through the ground station, after the rubidium atomic clock is locked to this 1PPS signal, the frequency of the rubidium atomic clock itself is calibrated, and the 1PPS signal output by the rubidium atomic clock is also synchronized to UTC.

[0004] Unfortunately, due to interference in satellite signal transmission, the 1PPS signal generated by the navigation receiver carries a lot of noise, and the 1PPS signal rate is too slow, so it usually takes more than 12 hours to use it to calibrate the rubidium atomic clock. Even if we have a low-noise 1PPS output by a high-grade clock as a standard on site, it still takes several thousand seconds to calibrate the frequency of the rubidium atomic clock, which is unacceptable in some situations that require a quick response. In this case, if we use an external instrument to measure the frequency of the rubidium atomic clock first and then calibrate the rubidium atomic clock manually or by program, the required instrument is complex and has specific professional requirements for the operator, so it is basically not feasible. Summary of the invention

[0005] An object of the present invention is to provide a rubidium atomic clock training system.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A rubidium atomic clock taming system includes: a rubidium quantum unit, a rubidium servo circuit unit, a constant temperature crystal oscillator, a whole machine frequency adjustment unit, a main control MCU, a first frequency divider, a second frequency divider, a third frequency divider, a first time digital conversion unit, a second time digital conversion unit, a digital control oscillator, a time difference processor, a digital phase-locked loop and a frequency multiplier, wherein:

[0008] The main control MCU is used to control and set the parameters of the rubidium quantum unit and the working parameters of the rubidium servo circuit unit to complete the frequency locking of the rubidium atomic clock;

[0009] After the frequency of the rubidium atomic clock is locked, the frequency signal of the rubidium atomic clock is compared with the frequency signal of the external input, and the main control MCU controls the rubidium atomic clock to adjust the frequency of the whole machine, thereby completing the taming.

[0010] Optionally, when the rubidium atomic clock starts working, the main control MCU sets the parameters of the rubidium quantum unit and the working parameters of the rubidium servo circuit unit, and the parameters include setting the temperature of the rubidium quantum unit. When the temperature of the rubidium quantum unit is heated to a specified temperature and the working parameters of the rubidium servo circuit unit are set, the frequency scanning circuit starts to work, the frequency is swept, the frequency of the rubidium atomic clock is locked, and the frequency of the constant temperature crystal oscillator is locked to the rubidium transition frequency of the rubidium quantum unit, and the locking of the rubidium atomic clock is completed.

[0011] Optionally, the frequency of the constant temperature crystal oscillator is 10 MHz.

[0012] Optionally, the frequency of the constant temperature crystal oscillator is used as the frequency output of the rubidium atomic clock and needs to be compared with the external input frequency signal. After comparison, the main control MCU calculates the frequency that needs to be adjusted, and the frequency adjustment unit of the whole machine starts working to calibrate the frequency of the constant temperature crystal oscillator to the same as the input frequency signal. The frequency of the rubidium atomic clock is calibrated, and time synchronization is performed after calibration.

[0013] Optionally, the frequency signal of the external input is 1PPS or 10MHz.

[0014] Optionally, the frequency signal input externally passes through the first frequency divider to output a first frequency-divided signal as the input of the first time digital conversion unit, which converts it into a first time and sends it to the time difference processor; the frequency signal of the constant temperature crystal oscillator enters the frequency multiplier and is input to the digitally controlled oscillator as a driving clock, and the main control MCU controls the digitally controlled oscillator and the second frequency divider to jointly output a second frequency-divided signal with the same frequency as the first frequency-divided signal as the input of the second time digital conversion unit, which converts it into a second time and sends it to the time difference processor; the time difference processor transmits the difference between the first time and the second time to the main control MCU, the main control MCU calculates the frequency that needs to be adjusted, and transmits it to the whole machine frequency adjustment unit, the whole machine frequency adjustment unit 13 adjusts the frequency, controls the whole machine frequency of the rubidium atomic clock to make the second frequency-divided signal synchronized with the first frequency-divided signal in phase, thereby completing the training.

[0015] The beneficial effects of the present invention are as follows:

[0016] The technical solution of the present invention realizes the satellite 1PPS taming function while also realizing the compatible 10MHz signal taming function. The problem of fast frequency calibration of the rubidium atomic clock can be solved without adding any additional instruments, and the calibration time is shortened to tens of seconds. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The specific implementation modes of the present invention will be further described in detail below in conjunction with the accompanying drawings.

[0018] Figure 1 A schematic diagram of the structure of a rubidium atomic clock taming system provided by an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0019] In order to more clearly illustrate the present invention, the present invention is further described below in conjunction with preferred embodiments and accompanying drawings. Similar components in the accompanying drawings are represented by the same reference numerals. It should be understood by those skilled in the art that the content specifically described below is illustrative rather than restrictive, and should not be used to limit the scope of protection of the present invention.

[0020] The embodiment of the present invention provides a rubidium atomic clock training system, such as Figure 1 As shown, the rubidium atomic clock taming system includes: a rubidium quantum unit 10, a rubidium servo circuit unit 11, a constant temperature crystal oscillator 12, a whole machine frequency adjustment unit 13, a main control MCU 14, a first frequency divider 15, a second frequency divider 16, a third frequency divider 17, a first time digital conversion unit 18, a second time digital conversion unit 19, a digital control oscillator 20, a time difference processor 21, a digital phase-locked loop 22 and a frequency multiplier 23, wherein,

[0021] The main control MCU 14 is used to control and set the parameters of the rubidium quantum unit 10 and the working parameters of the rubidium servo circuit unit 11 to complete the frequency locking of the rubidium atomic clock;

[0022] After the frequency of the rubidium atomic clock is locked, the frequency signal of the rubidium atomic clock is compared with the frequency signal of the external input, and the main control MCU controls the rubidium atomic clock to adjust the frequency of the whole machine, thereby completing the taming.

[0023] In a specific example, when the rubidium atomic clock starts working, the main control MCU 14 sets the parameters of the rubidium quantum unit 10, including setting the temperature of the rubidium quantum unit 10 and setting the working parameters of the rubidium servo circuit unit 11. When the temperature of the rubidium quantum unit 10 is heated to the specified temperature and the working parameters of the rubidium servo circuit unit 11 are set, the frequency scanning circuit starts to work, the frequency is swept over, and the frequency of the rubidium atomic clock is locked, that is, the frequency of the constant temperature crystal oscillator 12 is locked to the rubidium transition frequency of the rubidium quantum unit 10. At this time, the rubidium atomic clock is locked.

[0024] In a specific example, the frequency of the constant temperature crystal oscillator 12 is 10 MHz.

[0025] In a specific example, after the rubidium atomic clock is locked, the frequency of the constant temperature crystal oscillator 12 is used as the frequency output of the rubidium atomic clock. The accuracy does not meet the requirements and needs to be compared with the accurate frequency signal of the external input. After comparison, the main control MCU calculates the frequency that needs to be adjusted, and the whole machine frequency adjustment unit 13 starts working to calibrate 10MHZ to the same as the accurate frequency signal input. At this time, the frequency of the rubidium atomic clock is calibrated, and time synchronization can be performed after calibration.

[0026] In the embodiment of the present invention, the accurate frequency signal input externally may be selected as 1PPS or 10 MHz.

[0027] In a specific example, the accurate frequency signal 1PPS or 10MHz is input externally. The 1PPS signal input externally is passed through the first frequency divider 15 to output the first frequency-divided signal 31 as the input of the first time digital conversion unit 18. The first time digital conversion unit 18 converts it into the first time and sends it to the time difference processor 21; the 10MHz signal output by the constant temperature crystal oscillator 12 enters the frequency multiplier 23 and is input to the digitally controlled oscillator 20 as the driving clock 41. The main control MCU 14 controls the digitally controlled oscillator 20 and the second frequency divider 16 to jointly output the second frequency-divided signal 32 with the same frequency as the first frequency-divided signal 31 as the input of the second time digital conversion unit 19. The second time digital conversion unit 19 converts it into the second time and sends it to the time difference processor.

[0028] If the input of the first frequency divider 15 is 1PPS, the frequency division coefficient of the first frequency divider is 1, and the numerical control oscillator 20 is set to make the second frequency division signal 32 also 1Hz; if the input of the first frequency divider 15 is 10MHz, the frequency division coefficient of the first frequency divider is not 1, and the first frequency division signal 31 is made as high as possible, and the numerical control is also set to make the second frequency division signal 32 the same value as the first frequency division signal 31. After the frequency divider is set, the time difference processor is started, and the time difference processor transmits the difference between the first time and the second time to the main control MCU. The main control MCU calculates the frequency that needs to be adjusted and transmits it to the whole machine frequency adjustment unit 13. The whole machine frequency adjustment unit 13 adjusts the frequency and controls the whole machine frequency of the rubidium atomic clock to make the second frequency division signal 32 synchronized with the first frequency division signal 31, thereby completing the taming.

[0029] In another specific example, when the external input accurate frequency signal is 10MHz, a method for quickly calibrating the 10MHz rubidium atomic clock is: set the first frequency divider and the second frequency divider so that the first frequency division signal 31 and the second frequency division signal 32 have the same frequency and are as high as possible, start the digital phase-locked loop to lock, and then take out the numerical control oscillator value, from which the frequency of the rubidium atomic clock itself can be obtained, and the frequency of the rubidium atomic clock can be adjusted to complete the frequency calibration of the rubidium atomic clock. After the frequency of the rubidium atomic clock is calibrated, the input signal is switched to 1PPS, the first frequency divider and the second frequency divider are reset, and the time difference between the input 1PPS and the local 1PPS is measured, so as to quickly adjust and calibrate the local 1PPS output to synchronize the two. The combination of these two steps can quickly complete the frequency calibration and timing.

[0030] The technical solution of the present invention, by adding a time difference measurement with a variable frequency division coefficient and a digital phase-locked unit, enables the rubidium atomic clock to accept two signals, 1PPS and 10MHz, and even tame any frequency signal, thereby allowing the user to use navigation satellite timing, and also to use advanced atomic clocks such as cesium clocks and hydrogen clocks to quickly calibrate the frequency of the rubidium atomic clock. At the same time, the technical solution of the present invention can also allow the user to open-loop measure the frequency difference between the input 10MHz and the rubidium atomic clock itself, greatly increasing the user's flexibility. The technical solution of the present invention is small in size, low in cost, adaptable to a wide frequency range, and easy to integrate. In addition to the rubidium quantum unit and the constant temperature crystal oscillator, even all functions can be integrated into a chip, greatly enhancing the function and ease of use of the rubidium atomic clock.

[0031] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not limitations on the implementation methods of the present invention. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is impossible to list all the implementation methods here. All obvious changes or modifications derived from the technical solution of the present invention are still within the protection scope of the present invention.

Claims

1. A rubidium atomic clock training system, It is characterized in that include: Rubidium quantum unit, rubidium servo circuit unit, constant temperature crystal oscillator, whole machine frequency adjustment unit, main control MCU, first frequency divider, second frequency divider, third frequency divider, first time digital conversion unit, second time digital conversion unit, digital control oscillator, time difference processor, digital phase locked loop and frequency multiplier, wherein, The main control MCU is used to control and set the parameters of the rubidium quantum unit and the working parameters of the rubidium servo circuit unit to complete the frequency locking of the rubidium atomic clock; After the frequency of the rubidium atomic clock is locked, the frequency signal of the rubidium atomic clock is compared with the frequency signal of the external input, and the main control MCU controls the rubidium atomic clock to adjust the frequency of the whole machine, thereby completing the taming, wherein the frequency signal of the external input is 1PPS or 10MHz; When the rubidium atomic clock starts working, the main control MCU sets the parameters of the rubidium quantum unit and the working parameters of the rubidium servo circuit unit, wherein the parameters include setting the temperature of the rubidium quantum unit. When the temperature of the rubidium quantum unit is heated to the specified temperature and the working parameters of the rubidium servo circuit unit are set, the frequency scanning circuit starts to work, the frequency is swept, the frequency of the rubidium atomic clock is locked, and the frequency of the constant temperature crystal oscillator is locked to the rubidium transition frequency of the rubidium quantum unit. The locking of the rubidium atomic clock is completed. The frequency of the constant temperature crystal oscillator is used as the frequency output of the rubidium atomic clock, and needs to be compared with the external input frequency signal. After the comparison, the main control MCU calculates the frequency that needs to be adjusted, and the frequency adjustment unit of the whole machine starts to work, calibrates the frequency of the constant temperature crystal oscillator to the same as the input frequency signal, and the frequency of the rubidium atomic clock is calibrated, and the timing is performed after calibration; The frequency signal input externally passes through the first frequency divider, and outputs the first frequency-divided signal as the input of the first time digital conversion unit. The first time digital conversion unit converts it into the first time and sends it to the time difference processor; the frequency signal of the constant temperature crystal oscillator enters the frequency multiplier, and is input to the numerical control oscillator as the driving clock. The main control MCU controls the numerical control oscillator and the second frequency divider to jointly output the second frequency-divided signal with the same frequency as the first frequency-divided signal, which is used as the input of the second time digital conversion unit. The second time digital conversion unit converts it into the second time and sends it to the time difference processor; the time difference processor transmits the difference between the first time and the second time to the main control MCU, the main control MCU calculates the frequency that needs to be adjusted, and transmits it to the whole machine frequency adjustment unit. The whole machine frequency adjustment unit adjusts the frequency, controls the whole machine frequency of the rubidium atomic clock to make the second frequency-divided signal synchronized with the first frequency-divided signal, thereby completing the taming; Among them, when the frequency signal of the external input is 10MHz, the first frequency divider and the second frequency divider are configured to make the first frequency divided signal and the second frequency divided signal have the same frequency and a value as high as possible, and the digital phase-locked loop is started to lock. At this time, the numerical control oscillator value is taken out, and the frequency of the rubidium atomic clock itself can be obtained from this value. The frequency of the rubidium atomic clock is adjusted to complete the frequency calibration of the rubidium atomic clock. After the frequency calibration of the rubidium atomic clock, the input signal is switched to 1PPS, and the first frequency divider and the second frequency divider are reconfigured to measure the time difference between the input 1PPS and the local 1PPS, so as to adjust and calibrate the local 1PPS output to synchronize the two; The frequency multiplier is divided by the third frequency divider to output a 1pps output.

2. The rubidium atomic clock training system according to claim 1, It is characterized in that The frequency of the constant temperature crystal oscillator is 10 MHz.

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