It is used widely in automation and communication domain.The common way of measurement is change the input signal into rectangle waveform after modulation and pass-zero detection. The “and” operation of two input rectangle waveform will bring the phase difference pulse. We use this pulse as the control of counter. It means we take count of clock pulse during the phase difference pu...

As a new type of EMC test site, reverberation chamber has been developed very fast in recent years and got more and more attention because its outstanding advantages over traditional test sites in the following terms: costs, measurement time and effectiveness in simulating complex EM field.The EM field in the reverberation chamber must be statistically uniform and statistically isotropic. Ther...

With the development of science, the technique of micro current measurement and detect is indispensable. Micro current measurement technique is used in many fields and its development plays an important role in relate fields.Circuit for pA measurement was designed by analysis in micro current measurement method in this paper. By being analyzed two ordinary ways which are high input impedance m...

This paper discusses a high-precision frequency measurement method based on phase coincidence detection technology .This frequency measuring instrument synchronizes measuring gates, test signals and standard frequency signals by using essential regulations of phase difference relationship between periodic signals. So the instrument can avoid the counting error of plus or minus 1 word in theor...

With the development of computer technology, equipment industry is undergoing a change. The powerful processing and display capabilities of computer enhance data collection, analysis and expression of any aspect of the performance of equipment. A virtual instrument as the representative new equipment has changed the traditional instruments,it takes full advantage of computer hardware and soft...

The 21~(st) century is an era of information and internet. With the development of the computer, microelectronics and network technology, the Monitoring System of Power Quality develops towards network. It is the premise condition that strengthening management in power system operation and enhancing the operation level is to establish a scientific, accurate on-line Monitoring System of Power ...

AF/PSTM was designed by our group. This system use a tiny probe to scan the subtle singles on the surface of a sample, which break the confine of the tradition diffraction limit and has a resolving power in nanometer dimension. In one scanning the system gets tow AFM image and two optic image respectively (a index image and a trans image), however index image is a relative value which show the...

Energy and environment have become critical issues for the survival and development of human beings nowadays. Since bearing the advantages of non-pollution, time-saving, flexible-investment, room-saving, wind power has good economical and social benefits. With the wind turbine becoming larger and larger, and the load it endured is also very complicated, the problem of safety in the wind turbi...

With the set up of the new time service system of low frequency time-code in our country, it is urgent need to research the method and instrument for field strength measuring of the LF time-code signal. In this paper, this problem is researched according to prevenient experience, and a small size

With the development of power electronics, harmonic, which is produced by power electronic equipments, pollutes the power system more and more seriously. Not only harmonic influences the power system and equipments, but also the power energy wasting made by harmonic is increasing. This reduces the efficiency of power energy.The structure and measure method of the current measurement equipment...