Contactless data carrier, interrogator, contactless data carrier system, and method of acquiring data

A contactless data carrier has a measurement port receiving an external signal to be compared, a threshold generator that generates different threshold values, a comparator that compares the external signal with the threshold values, and a controller that controls the variable threshold generator on command from an interrogator and returns the comparison results to the interrogator. The comparison results returned to the interrogator may be the results of the individual comparisons, or information derived from a threshold value at which the comparison result changes. The contactless data carrier is small, lightweight, and inexpensive, and can be used to perform an essentially unlimited variety of measurements by connecting suitable sensors to the measurement port.