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

During the last years, measuring equipment has evolved toward the massive use of digital techniques and devices. The performance of analog-to-digital converters (ADC) and computing devices has constantly improved, and very accurate and flexible instruments can now be realized with bandwidths up to several kilohertz. Unfortunately, the transducers used to adapt the input signals to a suitable ADC input levels have not improved to the same extent so 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 Σ-Δ modulation techniques, that features a bandwidth wider than that of the traditional magnetic and capacitive voltage transformers. Specifications are provided on the transducer design, and the results of experimental tests on a lab prototype with primary voltage up to 500 V are reported