Meteorological Instrument Performance Characteristics

Instrument Performance Characteristics » Static Calibration » Linearization Error

If the systematic error increases or decreases linearly as values of the input change linearly, then the instrument suffers from a span error, and the static sensitivity [ ∂(Output) / ∂(Input) ] must be adjusted. With the span error and zero error removed during calibration, any remaining systematic error could be due to nonlinearity, which could either be the instrument’s true response to an input, as in the case of a thermistor (a temperature-sensitive semiconductor that produces a very large nonlinear change in resistance for a change in temperature) or the result of other error sources such as drift, hysteresis, or nonlinear span errors.

Generalized illustration of a calibration plot showing an example of a nonlinear sensor response, leading to a smaller nonlinear output (bottom curve) relative to the desired value.