A new low-cost voltage-to-voltage transducer for distorted signals

During the last years, measuring equipment has evolved toward the massive u se of digital techniques and devices. The performance of analog-to-digital converters (ADC) and computing devices has constantly improved, and very ac curate and flexible instruments can now be realized with bandwidths up to s everal kilohertz. Unfortunately, the transducers used to adapt the input si gnals to a suitable ADC input levels have not improved to the same extent s o that the metrological characteristics of a DSP-based measuring instrument are mainly determined by the input transducers. Improving the performance of such transducers is thus of the utmost importance. This paper proposes a new voltage-to-voltage transducer, based on a capacitive divider and the S igma-Delta modulation techniques, that features a bandwidth wider than that of the traditional magnetic and capacitive voltage transformers. Specifica tions are provided on the transducer design, and the results of experimenta l tests on a lab prototype with primary voltage up to 500 V are reported.