A Rubidium Clock Scanning Acquisition Assisted Locking Method

Abstract

The invention discloses a rubidium clock scanning and capturing auxiliary locking method which utilizes an existing rubidium clock locking telemetering module and an existing DDS frequency synthetic circuit for judgment. When a rubidium clock is not locked, the DDS frequency synthetic circuit adjusts an output FSK signal frequency according to a certain cycle, frequency stepping and a frequency range. A microwave frequency can change along with the change of the FSK signal according to the correlation of the microwave frequency and the FSK signal frequency. When the microwave frequency enters into a pull-in range of a rubidium clock frequency locking loop, the rubidium clock can be in a locking state, and therefore the scanning and capturing auxiliary locking function is achieved. According to the rubidium clock scanning and capturing auxiliary locking method, hardware composition is reduced. For example, a low frequency oscillator is removed. In addition, any interfering noise does not exist, and meanwhile, the method has the advantage of being easy to debug.

Description

technical field [0001] The invention relates to a rubidium clock scanning capture auxiliary locking method. Background technique [0002] Rubidium clock is the most widely used atomic clock. It has the advantages of small size, light weight, low power consumption, low price, high reliability, long life, and good short-term stability. It is convenient for miniaturization and mass production. Its work principle such as figure 1 shown. [0003] The output signal of the voltage-controlled crystal oscillator generates a microwave signal ν through frequency multiplication, synthesis and other measures 微波 (approximately 6834.6875MHz), sent to the physical part, that is, the microwave cavity of the rubidium atomic resonator, to excite the atomic transition and generate a resonance signal, so that the light intensity passing through the 87Rb absorption bubble changes, and the photosensitive detector detects this light signal It is detected and converted into an electrical signal a...

AI Technical Summary

Problems solved by technology

[0005] The existing expansion capture circuits are all based on the auxiliary locking of the servo circuit, and the biggest disadvantage is that auxiliary circuits such as hardware scanning oscillators are required

[0007] b. The servo-based auxiliary locking circuit finally superimposes the scanning level on the voltage control voltage terminal of the crystal oscillator. No matter how high the isolation degree is, it is impossible to completely achieve physical isolation. For high-precision rubidium clocks, the frequency stability index requirement is 3×10 -12 / 1s, crystal oscillator voltage control slope is 1×10 -7 / V or so, in theory, the voltage fluctuation control of the voltage control terminal of the crystal oscillator is required to be ≤0.03mV; if the noise is too large, the index performance of the whole machine will be reduced, and even the normal working state of the rubidium clock will be affected

[0008] It can be seen that the existing auxiliary locking method for rubidium clocks can no longer meet the needs of high-performance rubidium clocks, and a method that does not introduce additional interference noise sources is needed to replace

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