Research On Synchronous Sampling Measurement Of Broadband High Precision Impedance

The inductor is a very important physical quantity to measure the AC inductance. Different sizes and different scale inductor coils are used in electric power, traffic, metallurgy,electronics, IT, telecommunications and other industries.Its quality depends on the inductance in different frequencies and Q values, So it has important meaning to ensure the accurate measurement of inductance.Our inductance value traceability to the national inductance working medium. Currently only 100 mH inductive transfer index reached to 5uH/H(k=1). In the electromagnetic measurement standard system in our country, the inductance working standard has ability to trace in 1k Hz, Other frequency quantity values is obtained according to the distribution parameters.We have no trace device now, so we can only use commercial RLC Bridge to trace. The highest accuracy digital bridge is 1689 M RLC Bridge. The impedance measurement accuracy is 0.02%.D and Q measurement accuracy is 0.0001. Because we need to make sure the trace ability word at a reference broadband(50Hz-2.5kHz) reach to 0.01%,so we need to redesign a measurement system.Such precision impedance measure system use the method of improved voltage vector, use virtual location settings, capacitance compensation and channel calibration to improve the accuracy of measurement. using NI PXI-5922 data acquisition card to sample data. NI PXI-5922 digital instrument can collect the two signal synchronization, using the NI Flex II ADC technology, has a flexible, user-defined resolution, and in the 24 to 16 between any point sampling. The digital instrument has the incomparable sampling rate range up to 15 MS/s has on the market at present the highest resolution and dynametic range of NI, combined with the powerful Lab VIEW software development platfor m, Through the NI-scope drive to complete the configuration and initialization of PXI-5922,to set up a data collection module, sampling rate, sampling number, sampling form, a trigger signal and sampling channel, The realization of system control, data processing and data display and other functions. This system can realize the measurement of high precision fast, inductance 1H in different frequencies to achieve 0.01% accuracy.