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

Abstract

During the last few years, measuring equipment has evolved towards the massive use of digital techniques and devices. The performance of the Analog-to-Digital Converters (ADC) and the computing devices has constantly improved, and very accurate and flexible instruments can now be realized with bandwidth up to several kilohertzs. Unfortunately, the transducers used to adapt the input signals to the suitable ADC input levels have not improved in the same may, so that the metrological characteristics of a DSP-based measuring equipment are mainly determined by its input transducers. Hence, trying to improve the performance of such transducers is of utmost importance. This paper proposes a new voltage-to-voltage transducer, based on a capacitive divider and /spl Sigma//spl Delta/ modulation techniques. It features a bandwidth wider than that of traditional magnetic and capacitive voltage transformers. Indications are given on the transducer design, and the results of experimental tests on a lab prototype with primary voltage up to 500 V are reported.