Characterization of PXI-Based Generators for Impedance Measurement Setups

Multichannel digital sinewave generators play a key role in digital automated impedance bridges. Along with the technological progress in the development of commercial data acquisition (DAQ) boards, which brings with it improvements in their metrological and functional properties, it is possible to realize the DAQ-based high-precision multichannel generators. This paper describes the evaluation of properties of three commercial DAQs, available in the form of PCI eXtensions for Instrumentation modules and working as two-channel generators supervised by software developed by the authors. Due to the fact that the main application area of these generators is digital impedance bridges, this paper presents research results the most relevant for the impedance bridges, i.e., the stability of amplitude ratio and phase difference as well as total harmonic distortion and spurious-free dynamic range. The results and conclusion presented in this paper may be useful when choosing DAQs intended to be used in the multichannel generators.