Research On Parameters And Optimization On Circuits Of CPT Atomic Frequency Standard

This thesis mainly presents the work of two aspects:studing and obtaining the best operating parameters of our originally developed physics package, improving the original CPT atomic frequency standard circuit.Frequency stability of the CPT atomic frequency standard heavily depends on the performance of the physics package. By studying our developed physis package, we found out that:to the physics package, the strongest signal, the narrowest line width, and the least temperature frequency shift of the CPT signal all fall into range of70to72℃, and within the range the best CPT signal can be achieved; magnetic field induced CPT signal frequency shift is proportional to square of the Helmholtz coil current, and the least magnetic field induced shift is at about0.2mA; microwave power needs optimized according to the working temperature, to different temperature the microwave power for the strongest the CPT signal is different.The work of improving and optimizing the frequency standard circuit include that:improving on the photoelectric signal demodulating circuit to improve the signal-to-noise ratio of the microwave frequency identifying signal; realizing microwave power stabilization by increasing microwave power negative feedback; optimized the working parameters of phase-locked loop circuit to depress phase noise and improve spurious rejection ratio of the microwave signal; optimized constant current source circuit to reduce the noise of the Helmholtz coil current.