A system for measuring differences in a physical variable, such as temperature
or voltage, by utilizing predictable behavior in the relative drift over time of
reference curves representative of offset, and other measurement parameters for
various circuit elements. In an initial calibration mode, the system records several
reference curves, correlating ambient condition to offset, and, optionally, other
parameter measurements acquired from circuit elements. These reference curves representing
drift behavior, among electrical components, can be updated for time drift at a
single, current arbitrary ambient temperature, the measurements for which can be
obtained quickly and applied as a time drift correction to the reference curves,
without interrupting normal system operation, to provide a compensated difference
measurement between the different values of the physical variable. Additionally,
the system dynamically tracks cumulative system errors, in order to calculate optimal
system resolution, based upon current operating conditions.
