An Ultra-high Resolution Phase Difference Measurement meter

Conventional linear phase comparison meters are used widely in the measurement of the frequency and stability. It can also be used in the measurement of length or distance in the navigation and orientation. Phase comparison methods not only reduce the cost of system, but also enhance precision, which can reach the measurement resolution of 10^-13/^tau in time domain. By the research on the major factors of precision effect of in the measurement of the length with phase comparison method, such as the linearity and trigger error, a solution to the improvement of the high precision is proposed in this paper. The avoidance of the dead region and the improvement of the linearity can be realized in small scope by sampling and phasing the geminated signals, controlling the region of the discriminator and phase displacing of the fixed region. In order to improve precision, this measuring technique must reduce trigger error as much as possible. The trigger error can be decreased by small signal reshaping, frequency transformation and wave filtering. In addition, the temperature shift of the whole circuit can be improved by the supply power of the low noise, the low shift & the high stability, the simple self-adjustment technique for the shift and the filtering treatment. Besides, by the choices of circuit components and the improvement of circuit design, output saturation voltage shift can be conquered and higher precision can be obtained. In this paper, the measurement precision of length or distance can be reached 0.1 ps-C. The change on the delay in the method of the linear can reflect the subtle change on the object distance. By collecting the data of the stimulated time of the phase change, the data can be transferred into the measurement of the distance or the length so as to realize the measurement of the subtle change on the distance.