Variable Frequency Oscillator-Based Resistive Sensor Interfaces Using VCII

This work deals with the realization of oscillator-based resistive sensor interfaces using a second-generation voltage conveyor (VCII). In particular, novel configurations of sinusoidal variable frequency oscillators (VFO) are presented and analyzed in detail. As discussed, the oscillation frequency can be tuned by varying a single resistor in the circuit. To the authors’ best knowledge, this is the first reported case of sinusoidal single-resistor controlled oscillators (SRCO) using VCII. Thanks to this property, the circuit is a very ideal candidate for implementing an electronic interface for resistive sensors. A theoretical analysis of the circuits is conducted to discuss their operation and outline the design process. Finally, simulated and experimental results using commercially available components are presented to validate the theoretical analysis and assess the circuit performance as resistive sensor interfaces.