A novel method on signal measurement in the presence of interference’s phase correlating with excitation is proposed.Based upon the analysis of voltage-to-frequency convertor’s（VFC）low-pass property

conclusion that correct set of the count-time of the VFC’s output pulse can completely reject sinusoid or non-sinusoid interference is achieved

furthermore

makeing use of interference’s phase correlating with excitation

a circuit capable of effectively removing the phase correlated interference according to the excitation’s frequency is designed.Tests indicate that this method can satisfy with the requirement

compared with other methods

the method is simple circuit

low-cost and flexible adjustment of resolution and measuring time.