Order Of Magnitude Better Than Picoseconds (ps) Frequency Standard Technology And High-precision Frequency Measurement

With the rapid development of science and technology, measurement of frequency, time and the relative control technology has occupied a important position in every field of science and technology, specially in metrology, electronic technology, information science, communication, astronomy and electronic instrument. In international trend, accuracy and stabilization improve very quickly by one order of magnitude every 6-8 years. The current accuracy and stabilization have reached1 10-15 and 1 10-14 /5 respectively and high stable crystal oscillator about10-13 / is used widely. But the apparatus which measure the high stable crystaloscillator cannot meet requirements in our country, a certain extent gap with other country. There are two reasons: the measure technology and the measure method. Some new discussion and study in the measure technology and the measure method of frequency and time is described in this paper.In the comparison of frequency standard, the ordinariest and the simplest method is phase comparison. In this method, the phase difference between two compared signals that have same nominal frequency can be converted into voltage signal by phase detector. The voltage signal varies linearly with the phase difference and can be displayed or recorded by some instruments. At last, the stability of frequency can be obtained according to the case that the phase between two frequency source varies with time. The measurement precision mainly depends on two aspect, one is the phase noise of frequency standard, the other is the linearity of phase detector in the range from 0 to 360. Because the nonlinearity of phase detector exists near 0 and 360, the measurement precision is limited. According to the feature of each nominal frequency, two new measurement methods are discussed in the second chapter of this paper. The two methods can reduce the phase noise, eliminate the effect of nonlinearity and promote the measurement precision by taking measure.The ?1 word count error exists in nearly all kinds of digital time and frequency measuring instrument and it affects the instrument's measuring precision tremendously. To increase the instrument's measuring precision, it is of importance to decrease its influence. This paper discusses a new, precise short time interval measuring method that is based on the quantized time delay. It decreases the +-1 word count error efficiently. The method can be used widely in high precision frequency, time and phase measurement. Combined with a kind of precise, constant gate's measuring method that is derived from the several period synchronization measuring method, high speed, high precision, successive frequency measurement can be fulfilled. It adapts well to the sensor signal measurement of non-frequency. This paper introduces the principle of this method and a measuring system completed by CPLD in detail. This method was used in two projects and good results were gotten. We believe, in the auto control system of the spaceflight, aviation, national defence, thismethod will have a great future.It's focus on optical frequency measurement inland and abroad. It's very significance to exploit a kind of new method in optical measurement for establishing optical frequency standards. According to development of inland and abroad, a new measurement method has been put forward that make use of the periodic characteristic of the phase difference between two arbitrary frequency signals. In the light of Lissajous graph, we complete comparison of radio frequency and microwave with 105 rates relationship in technique. On the ground of common characteristic of frequency signals, this method can be developed to comparison of microwave frequency and optical frequency to accomplish optical frequency measurement.