Method for optimizing the start-up characteristics of a rubidium atomic clock

Abstract

The application relates to the technical field of atomic clocks, in particular to a method for optimizing the starting characteristics of a rubidium atomic clock, which comprises the following steps: step 1: measuring the relationship between the light intensity and the output frequency accuracy of a certain determined rubidium atomic clock after starting; step 2: theoretically analyzing and testing the relationship between the C-field current and the output frequency accuracy; step 3: determining the relationship between the light intensity telemetry and the C-field current according to the data obtained from steps 1 and 2; step 4: determining the compensation coefficient according to the relationship between the light intensity telemetry and the C-field current obtained in step 3, combining the light intensity telemetry and the C-field current by designing a compensation circuit; and step 5: adjusting the parameters of the compensation circuit, so that the starting characteristics of the rubidium atomic clock are optimized. The application makes the operation of adjusting the starting characteristics of the rubidium atomic clock simple, widens the adjustment range of the starting characteristics of the rubidium atomic clock, reduces the development cost of the rubidium atomic clock, and improves the yield of the rubidium atomic clock.

Description

Technical Field

[0001] This application relates to the field of atomic clock technology, and more specifically, to a method for optimizing the power-on characteristics of a rubidium atomic clock. Background Technology

[0002] Power-on characteristics, as one of the important indicators of rubidium atomic clocks, mainly describe the process of rubidium atomic clocks from power-on to stable operation. Rubidium atomic clocks used in engineering applications are frequently powered on, and it is desirable to shorten the process from power-on to use as much as possible. Therefore, the power-on characteristics of rubidium atomic clocks are of great importance. Power-on characteristics usually include three parameters: lockout time, stable operating time, and power-on process.

[0003] When a rubidium atomic clock is first powered on, its internal crystal oscillator is in a free working state, resulting in poor frequency accuracy. As the power-on time increases, the internal temperature control circuit of the rubidium atomic clock gradually enters a balanced state, and other circuits also gradually enter a normal working state. After a certain moment, the output frequency of the crystal oscillator is locked by the atomic transition frequency. This time is called the lock-in time. The stable working time refers to the time required for the rubidium atomic clock to reach a stable working state from power-on, with all indicators meeting the technical requirements. The power-on process is usually represented by a curve, showing the process of the rubidium atomic clock from power-on to frequency stabilization.

[0004] The adjustment and optimization of power-on characteristics have a significant impact on the overall performance of rubidium atomic clocks. In engineering, the power-on characteristic indicators should be minimized as much as possible so that the rubidium atomic clock can quickly reach the required specifications after power-on, thereby achieving the best performance of the rubidium atomic clock. Currently, the main problem with adjusting the power-on characteristics is that the frequency accuracy of the rubidium atomic clock changes significantly after locking. It is difficult to achieve an absolute frequency accuracy better than 3E-10 within half an hour after locking, which makes it difficult to further improve the power-on characteristics of the rubidium atomic clock. Existing methods for improving the power-on characteristics of rubidium atomic clocks not only require a lot of theoretical analysis, but can also only be adjusted for a certain type of rubidium atomic clock, which has a large degree of uncertainty. Summary of the Invention

[0005] The main objective of this application is to provide a method for optimizing the start-up characteristics of a rubidium atomic clock. This method combines light intensity telemetry, C-field current, and the frequency accuracy of the rubidium atomic clock. By utilizing the dynamic change in light intensity telemetry after the rubidium atomic clock is locked, the light intensity-frequency coefficient during the start-up phase of the rubidium atomic clock is automatically compensated, thereby optimizing the start-up characteristics of the rubidium atomic clock.

[0006] To achieve the above objectives, this application provides a method for optimizing the start-up characteristics of a rubidium atomic clock, comprising the following steps: Step 1: Measuring the relationship between light intensity and output frequency accuracy after a given rubidium atomic clock is turned on; Step 2: Theoretically analyzing and testing the relationship between C-field current and output frequency accuracy; Step 3: Determining the relationship between light intensity telemetry and C-field current based on the data obtained in Step 1 and Step 2; Step 4: Determining the compensation coefficient based on the relationship between light intensity telemetry and C-field current obtained in Step 3, thereby designing a compensation circuit to combine light intensity telemetry and C-field current; Step 5: Adjusting the parameters of the compensation circuit to optimize the start-up characteristics of the rubidium atomic clock.

[0007] Furthermore, in step 4, the compensation circuit includes an amplifier circuit, a reference circuit, a subtraction circuit, and a C-field circuit.

[0008] Furthermore, the amplifier circuit includes resistors R7 and R8, inductor L1, capacitor C4, resistor R6, capacitor C2, and operational amplifier N1.

[0009] Furthermore, the reference circuit includes resistors R13 and R14, capacitor C5, and operational amplifier N2.

[0010] Furthermore, the subtraction circuit includes resistors R10, R11, R12, and R9, capacitor C3, and operational amplifier N3.

[0011] Furthermore, the C-field circuit includes resistor R2, resistor R1, capacitor C1, and operational amplifier N4.

[0012] Furthermore, in step 4, the reference voltage in the compensation circuit is isolated by a voltage follower.

[0013] Furthermore, in step 4, an LC filter is provided at the input interface of the compensation circuit.

[0014] The present invention provides a method for optimizing the start-up characteristics of a rubidium atomic clock, which has the following beneficial effects:

[0015] This application combines light intensity telemetry, C-field circuit, and rubidium atomic clock output frequency accuracy. When light intensity changes, the change in C-field current is used to compensate for the change in rubidium atomic clock frequency accuracy caused by the change in light intensity. This not only simplifies the operation of adjusting the start-up characteristics of the rubidium atomic clock, but also expands the adjustment range of the start-up characteristics of the rubidium atomic clock, reduces the development cost of the rubidium atomic clock, and improves the yield of the rubidium atomic clock. Attached Figure Description

[0016] The accompanying drawings, which form part of this application, are used to provide a further understanding of the application and to make other features, objects, and advantages of the application more apparent. The illustrative embodiments and descriptions of this application are used to explain the application and do not constitute an undue limitation of the application. In the drawings:

[0017] Figure 1 This is a schematic diagram of a compensation circuit for a method to optimize the power-on characteristics of a rubidium atomic clock according to an embodiment of this application;

[0018] In the diagram: 1-Amplifier circuit, 2-Reference circuit, 3-Subtraction circuit, 4-C-Field circuit. Detailed Implementation

[0019] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0020] like Figure 1 As shown, this application provides a method for optimizing the start-up characteristics of a rubidium atomic clock, comprising the following steps: Step 1: Measuring the relationship between light intensity and output frequency accuracy after a given rubidium atomic clock is turned on; Step 2: Theoretically analyzing and testing the relationship between C-field current and output frequency accuracy; Step 3: Determining the relationship between light intensity telemetry and C-field current based on the data obtained in Step 1 and Step 2; Step 4: Determining the compensation coefficient based on the relationship between light intensity telemetry and C-field current obtained in Step 3, thereby designing a compensation circuit to combine light intensity telemetry and C-field current; Step 5: Adjusting the parameters of the compensation circuit to optimize the start-up characteristics of the rubidium atomic clock.

[0021] Specifically, in traditional rubidium atomic clocks, light intensity telemetry is generally only used to observe the intensity of the rubidium bulb and the resonance in the absorber; it is a telemetry signal. The C-field current refers to the current in C-field circuit 4. There is no direct connection between the two. However, theoretical analysis and experiments have shown that there is a certain relationship between the light intensity telemetry and the output frequency accuracy of the rubidium atomic clock. When the light intensity telemetry changes, the frequency accuracy also changes accordingly. The C-field mainly consists of the C-field coil and C-field circuit 4. The main function of the C-field coil is to generate a weak static magnetic field parallel to the microwave magnetic field, allowing... 87The hyperfine level of the Rb atom's ground state further splits, selecting two levels with mF = 0, while all transitions between other sub-levels with mF ≠ 0 are excluded from the loop's capture band. The C-field circuit 4 provides a stable current to the C-field coil. Adjusting the C-field current allows for adjustment of the rubidium atomic clock's output frequency accuracy. In the rubidium atomic clock, the C-field current and output frequency satisfy the following relationship, where f0 is a constant.

[0022]

[0023] Where f0 is a constant, N is the number of turns of the coil, I is the field current C, and R is the radius of the coil.

[0024] In addition, the startup characteristics of rubidium atomic clocks are generally optimized using the following two methods: 1. Adjusting the pressure ratio of the buffer gas in the absorber and filter bulbs of the rubidium atomic clock; 2. Adjusting the temperature of the lamp chamber and cavity chamber in the physical components of the rubidium atomic clock. The basic principle of both methods is to reduce the optical frequency shift, thereby optimizing the startup characteristics. These methods not only require extensive theoretical analysis but can also only be applied to a specific type of rubidium atomic clock. Furthermore, considering that many steps in the production process of rubidium atomic clocks are manual, such as the filling of the bulb, absorber, and filter bulb, and the assembly of the cavity system, the performance indicators of each rubidium atomic clock are inconsistent. Moreover, the above optimization methods require… Extensive testing was conducted, including measuring the start-up characteristics of the rubidium atomic clock, the frequency shift of the buffer gas pressure, the influence of lamp temperature and cavity temperature on accuracy, and the frequency shift of microwave power. The method for optimizing the start-up characteristics of the rubidium atomic clock provided in this application is simple and practical. Based on the above experimental principles, a compensation circuit is designed to combine the light intensity telemetry, the C-field circuit 4, and the output frequency accuracy of the rubidium atomic clock. When the light intensity changes, the change in the C-field current is used to compensate for the change in the frequency accuracy of the rubidium atomic clock caused by the change in light intensity. This can compensate for the original frequency change caused by the change in light intensity, reduce the light intensity-frequency sensitivity coefficient of the rubidium atomic clock, and thus achieve the purpose of optimizing the start-up characteristics of the rubidium atomic clock. The specific optimization steps are as follows: First, the light intensity-frequency coefficient after the rubidium atomic clock is turned on is obtained through testing. Then, the relationship between the C-field current and frequency accuracy is tested. Based on the test data, a compensation circuit is designed, and the corresponding resistance value is selected to determine the compensation coefficient. Then, when the rubidium atomic clock is turned on again, the resistance value of the resistor in the compensation circuit is finely adjusted according to the newly tested light intensity-frequency coefficient, so as to obtain the optimal compensation effect for the rubidium atomic clock's turn-on characteristics.

[0025] Furthermore, in step 4, the compensation circuit includes an amplifier circuit 1, a reference circuit 2, a subtraction circuit 3, and a C-field circuit 4. In the compensation circuit, the light intensity telemetry signal, after passing through the amplifier circuit 1, is connected to one end of resistor R10 in the subtraction circuit 3. Simultaneously, the power supply voltage generates a reference voltage through the reference circuit 2, which is connected to one end of resistor R11 in the subtraction circuit 3. The subtraction circuit 3 subtracts the reference voltage from the amplified light intensity telemetry signal, thus forming a voltage. Finally, this voltage is used to power the C-field coil, thereby indirectly realizing the correlation between light intensity telemetry and C-field current. Therefore, when the light intensity telemetry changes, the current in the C-field coil will change accordingly. This achieves the goal of adjusting the C-field current by changing the light intensity telemetry, thereby altering the output frequency accuracy of the rubidium atomic clock and ultimately optimizing the start-up characteristics of the rubidium atomic clock. By adjusting the resistance values ​​of the corresponding resistors in the compensation circuit, the input reference voltage and the input light intensity can be adjusted. During the optimization process, the optimal power-on characteristics of the rubidium atomic clock can be achieved by fine-tuning the resistance values ​​of the corresponding resistors. Furthermore, if the optimization is not satisfactory in one attempt, multiple iterations of optimization can be performed.

[0026] Furthermore, amplifier circuit 1 includes resistors R7 and R8, inductor L1, capacitor C4, resistor R6, capacitor C2, and operational amplifier N1. Amplifier circuit 1 is mainly used for amplifying optical intensity telemetry signals.

[0027] Furthermore, reference circuit 2 includes resistors R13 and R14, capacitor C5, and operational amplifier N2. The power supply voltage VCC is divided by resistors R13 and R14 and then isolated by operational amplifier N2 to generate a reference voltage.

[0028] Furthermore, subtraction circuit 3 includes resistors R10, R11, R12, and R9, capacitor C3, and operational amplifier N3. Subtraction circuit 3 is mainly used for subtraction between the amplified light intensity telemetry signal and the reference voltage.

[0029] Furthermore, the C-field circuit 4 includes resistors R2 and R1, capacitor C1, and operational amplifier N4. The C-field circuit 4 is mainly used to provide current to the C-field coil, and is connected to the two ends of the C-field coil through W1 and W2.

[0030] Furthermore, in step 4, the reference voltage in the compensation circuit is isolated using a voltage follower. This isolation is primarily to ensure the quality of the reference voltage, providing impedance matching while also improving the signal's load-carrying capacity.

[0031] Furthermore, in step 4, an LC filter is installed at the input interface of the compensation circuit. The LC filter is primarily used to ensure the quality of the optical intensity telemetry signal transmission and to reduce interference to other circuits.

[0032] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for optimizing the start-up characteristics of a rubidium atomic clock, characterized in that, Includes the following steps: Step 1: Measure the relationship between the light intensity and the accuracy of the output frequency after a specific rubidium atomic clock is turned on; Step 2: Theoretically analyze and test the relationship between the C-field current and the accuracy of the output frequency; Step 3: Determine the relationship between light intensity telemetry and C-field current using the data obtained in Step 1 and Step 2; There is a certain relationship between the light intensity telemetry and the output frequency accuracy of the rubidium atomic clock. When the light intensity telemetry changes, the frequency accuracy will also change accordingly. The C field is composed of a C field coil and a C field circuit. The following relationship exists between the field current and the output frequency: Where f0 is a constant, N is the number of turns of the coil, I is the field current C, and R is the radius of the coil; Step 4: Based on the relationship between the light intensity telemetry and the C-field current obtained in Step 3, determine the compensation coefficient, and then design a compensation circuit to combine the light intensity telemetry and the C-field current. The compensation circuit includes an amplifier circuit, a reference circuit, a subtraction circuit, and a C-field circuit. The amplifier circuit includes resistors R7 and R8, inductor L1, capacitor C4, resistor R6, capacitor C2, and operational amplifier N1. The reference circuit includes resistors R13 and R14, capacitor C5, and operational amplifier N2. The subtraction circuit includes resistors R10, R11, R12, and R9, capacitor C3, and operational amplifier N3. The C-field circuit includes resistors R2 and R1, capacitor C1, and operational amplifier N4. In the compensation circuit, the light intensity telemetry signal is amplified and then connected to one end of resistor R10 in the subtraction circuit. At the same time, the power supply voltage generates a reference voltage through the reference circuit and is connected to one end of resistor R11 in the subtraction circuit. The subtraction circuit subtracts the reference voltage from the amplified light intensity telemetry signal to form a voltage. Finally, this voltage is used to power the C-field coil, thus indirectly realizing the correlation between light intensity telemetry and C-field current. Step 5: Adjust the parameters of the compensation circuit to optimize the start-up characteristics of the rubidium atomic clock; When the light intensity telemetry changes, the current in the C-field coil changes accordingly. This allows the C-field current to be adjusted by changing the light intensity telemetry, thereby altering the output frequency accuracy of the rubidium atomic clock and ultimately optimizing its start-up characteristics.

2. The method for optimizing the start-up characteristics of a rubidium atomic clock as described in claim 1, characterized in that, In step 4, the reference voltage in the compensation circuit is isolated by a voltage follower.

3. The method for optimizing the start-up characteristics of a rubidium atomic clock as described in claim 1, characterized in that, In step 4, an LC filter is provided at the input interface of the compensation circuit.

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