Sensor Resolution

Sensor resolution is the minimum detectable change in input $x$. It’s the smallest amount we can change the input before we can expect the output to change.

Analog:

• Minimum measurable change in input value
• Often expressed as a percent value of full scale
• Example: 0 to 1 mm linear position sensor with $0.1\%$ resolution. What’s the smallest change in displacement that we can measure? $0.001\times 1\text{ mm}=1\mu m$

Digital:

• Change in input required to cause a 1-bit change in output.
• Example: Digital angle sensor module with $0°-90°$ input and a 12-bit output. The smallest change in angle would be:

$$\frac{90°}{2^{12}}=21.97\text{ milli-degrees}$$

• Example: Temperature sensor with an instrument span of 100 K and a 10-bit output has a resolution of

$$\frac{100\text{K}}{2^{10}}=97.7\frac{\text{ mK}}{\text{bit}}$$