Sensor Transfer Function

A transfer function, in the context of sensors, expresses output as a function of input. In SYDE 252 or filters, “transfer functions” means something specific.

Units for a transfer function are:

$$\left[\frac{\text{output state}}{\text{input state}}\right]$$

which could be [V/kPa], [Hz/N], etc.

For example, a resistive pressure sensor could have:

$$A=10\left[\frac{\text{k}\Omega }{\text{kPa}}\right]$$

this means that its resistance is $10\text{ k}\Omega$ for every $\text{kPa}$ of applied pressure. This notation $A$ is mimics the gain of an op-amp.

These can be often be much more complex, such as:

$$R_{out}=10P_{\text{kPa}}+0.02P_{\text{kPa}}^2+7[\text{k}\Omega ]$$

Transfer functions can include frequency effects, like lowpass behaviour.