A rubidium atomic frequency standard and its frequency absolute value correction circuit

Abstract

The invention discloses a rubidium atomic frequency standard and a frequency absolute value correction circuit thereof, belonging to the field of atomic frequency standards. The rubidium atomic frequency standard includes a voltage-controlled crystal oscillator, a physical unit and an electronic circuit, and the physical unit includes a microwave cavity, a C field coil arranged outside the microwave cavity, and a constant current source device electrically connected to the C field coil , the physical unit further includes a frequency absolute value correction circuit, and the frequency absolute value correction circuit includes a variable resistor connected in series between the constant current source device and the C-field coil. In the embodiment of the present invention, the magnitude of the current in the C field coil is adjusted by the frequency absolute value correction circuit, which changes the strength of the magnetic field provided by the atoms in the physical unit, and can adjust the atomic transition frequency, and then fine-tune the output frequency of the entire atomic frequency standard , to ensure the accuracy and stability of the atomic frequency standard.

Description

technical field [0001] The invention relates to the field of atomic frequency standards, in particular to a rubidium atomic frequency standard and a frequency absolute value correction circuit thereof. Background technique [0002] The atomic frequency standard is a frequency source with excellent stability and accuracy, and has been widely used in the fields of satellite positioning, navigation and communication, instrumentation, and astronomy. The rubidium atomic frequency standard has become the most widely used atomic frequency standard because of its advantages of small size, light weight, low power consumption, and low cost. [0003] The rubidium atomic frequency standard mainly includes a voltage-controlled crystal oscillator, a physical unit and an electronic circuit. The physical unit includes: a spectral lamp, an integrated filter resonant bubble, a microwave cavity for generating a microwave field, a C-field coil, a photocell for detecting an optical signal, a co...

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Problems solved by technology

However, because the magnetic field actually generated by the C field coil is not uniform, the transition spectrum of the rubidium atom is not absolutely symmetrical, and the transition frequency of the rubidium atom will deviate from the standard frequency of 6.8346975GHz, which is the ground state hyperfine 0-0 of the aforementioned rubidium atom. transition frequency

In this way, the frequency of the microwave interrogation signal generated by the electronic circuit cannot be aligned with the standard frequency of the transition line of the rubidium atom, and the voltage control signal obtained after the quantum frequency discrimination signal generated by the photoelectric cell is inaccurate after synchronous phase discrimination processing, which leads to the locking of the voltage control signal The output frequency of the VCO is inaccurate

[0005] The existing method to improve the accuracy of the output frequency of the rubidium atomic frequency standard is to use an external frequency adjustment circuit to correct the output frequency of the rubidium atomic frequency standard. However, the increase of the external frequency adjustment circuit will lead to the stability of the output frequency signal degree of variation

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