An Optimization Approach to Eliminate Crosstalk in Zero-Potential Circuits for Reading Resistive Sensor Arrays

Crosstalk is a well-known problem in resistive sensor arrays (RSAs). The zero-potential method (ZPM) is a commonly used readout circuit that uses multiplexers and demultiplexers to reduce the main sources of crosstalk. However, the internal resistors of these switches cause a secondary crosstalk in the RSA that alters the RSA sensor values read. The solution to the effects of this secondary crosstalk is still a case of study. In previous literature, these resistances have been considered as known and, in most cases, equal for all switch channels. However, in a real situation, they are unknown and may vary between channels. In this work, a least-squares (LSQR) method is presented to obtain the true values of the switches from the read voltage signals. Calibration columns are added to the RSA for this purpose. To prove the performance of the method proposed, several simulations have been carried out with different values of RSA sensors, switch resistances, size of the RSA, and noise level. Results show that the proposed LSQR method allows obtaining simultaneously accurate values for both the RSA sensors and switch internal resistors. In this way, the problem of secondary crosstalk is neutralized. It also shows better performance when compared with existing approaches.