Abstract: In the time and frequency field, Allan variance is utilized in general to indicate frequency stability. Allan variance can not inhibit Flicker PM effectively because it′s defective algorithm. In order to reduce the impact of noise on frequency stability, frequency stability should be indicated by modified Allan variance. Modified Allan variance for inhibition mechanism of Flicker PM is analyzed. Through the satellite commonview method, the comparative data of hydrogen clock and UTC(NIM) are evaluated. Then, the noise model is used to demonstrate the results of evaluation. The effectiveness of the modified Allen variance against Flicker PM inhibition is verified.

Key words: frequency stability, Allan variance, modified Allen variance, Flicker PM, commonview time comparison, time and frequency, hydrogen clock