| With the development of modem electronic technology and scientific base research, the measurement and control technology of time and frequency are becoming more and more important in various fields of science and technology.In recent years,both at home and abroad,the accuracy and stability of frequency standard has been improved rapidly,with more extensive scope of application.But the measurement and comparison technology of frequency signal with high accuracy and stability can not meet the requirements yet.At present,along with the tremendous progress in China's national defense and space technology,more precise measurement and processing of time and frequency are also required,but the problems appears that the precise of measurement and control are not enough and the cost are still high.To improve the accuracy of measurement and comparison of time and frequency, raising the compensation effects to crystal oscillators,this dissertation has made a research in the frequency measurement of high-precision,frequency standard comparing, short time interval measurement and temperature-compensated crystal oscillator.The main contributions and innovation points are as follows:First,a method on frequency measurement of high-precision and a method on frequency standard comparison are proposed,both based on the principle of phase coincidence detection.Using the concept of the greatest common factor frequency and the principle of phase coincidence detection,with fine property of FPGA devices, the high-precision frequency meter and frequency standard comparator have been developed.The actual test data indicates that the accuracy of frequency measurement can reach up to 10-11/s order of magnitude and frequency standard comparison 10-11/s order of magnitude.Secondly,a short time interval measurement method and a frequency measurement method are proposed,which are both based on the technique of delay-chain.If the delay time of each delay line in delay chain is the same and meets some relations to the period of reference signal,the measure results of short time interval or frequence can decrease the impact of±1 counting error.The measurement effect of this method is equivalent to that what can be obtained by increasing the frequence of reference signal by several or tens times.So this method provides a new idea and technique for short time interval measurement and frequency measurement.Thirdly,a method of short time interval measurement based on length vernier is proposed.Through the study on this method,the author applied for the National Natural Science Foundation Project "research on the precision time interval measurement based on the length vernier",and has been approved(No.10703004 approval).Using the high stability of signal transmission,with the start and stop signal transmission in two length vernier separately,and then by coincidence detection of two delayed signals,the result can achieve a measurement resolution at least dozens ofps.The fourth,two control methods of temperature-compensated crystal oscillator are proposed.One is based on the stress-temperature effect of secondary plating,and another the compensation capacity-temperature characteristic of sensor and analog storage.The two methods both have a better compensation effect,simple crystal oscillator structure and low cost.This method provides a new way for temperature-compensated crystal oscillator.All of the proposed methods in this thesis are designed,simulated,experimented, testing,and compared with related schemes through and through in order to prove their validities and advantages.
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