Research And Instrument Achievement Of New Frequency Standard Comparison Method

This paper mainly introduces a new method and a practical comparison resolution of frequency standards which based on dual-phase detection theory.This system uses pulses to fill in the phase difference signal and count the number of pulses which are filled in. Using the two groups of numbers at the same time, we get two phase-comparison curves. By combining the two curves we can get a very good linear phase-comparison curve, which eliminates dead region and nonlinear phenomena in traditional phase detection curve.In this system, the realization of phase coincidence detecting circuit and the parts of counting are programmed and designed in the EP1C3T144 chip, which is one of the series of ALTERA Corporation Cyclone; The computation and the display work are mainly completed by MCU, which is one serie of ATMEL Corporation's MCS-51;Software improvements include optimizing the mothod dealing with the colleted data, improvement on display fuction and user interface in which using the technique of virtual instrument.It turns out that this system has several merits: a wide frequency range that can be measured, a high measuring precision, simple circuit etc.