Precise Frequency Comparison System Using Phase Coincidence Demarcation.

The precise frequency comparison system is of great importance in many applications. A frequency comparison method based on the phase coincidence demarcation (PCD) is proposed, and a frequency comparison system based on the proposed method is realized. The proposed method solves the uncertainty problem of the phase coincidence detection circuit by using two analog-to-digital converter (ADC) chips to demarcate the phase coincidence points. The test results indicate that the precision of the realized frequency comparison system is 10−16 (Allan deviation) at 1000 s. [ABSTRACT FROM AUTHOR]