Abstract：Based on the new generation analog-digital mixed phase-locked loop and SOHM-4 maser of Shanghai Observatory, the experiments mainly analyzed the contribution brought by parameters of phase-locked loop to both the short-term frequency stability and the signal-side-band phase noise of the output signal of the hydrogen masers. By theoretical analysis and experimental verification, the best loop parameters matching with the specific maser of high Q value is explored. Results showed that the parameter setting of phase-locked loop could definitely influence specifications of the masers output signal. And the improved phase-locked loop and main electronic system could upgrade the frequency stability of the maser to 1.7×10-13/1s, 3.3×10-14/10s, 9.1×10-15/100s, 2.9×10-15/1000s, 1.4×10-15/10000s,half-amplitude upper to the former specifications in each sample time.
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2012, Vol. 33 
