Precision digital filters for high voltage impulse measurement systems

This paper reports the design, testing and practical applications of two types of high order FIR digital filters for noise reduction and data smoothing of high voltage impulse waveforms. Particular attention is paid to the estimation of the error limits introduced by the digital filters. The error estimation involves the analysis of the frequency components of the impulse waveforms, the ripple calculation of the filters and testing of the filters with simulated and real impulse waveforms. The relationships between the filter parameters and the required filter accuracies are established.