1.3 Signal Scale and Resolution

To maximize the resolution of a signal, scale the input signals to the measurement range of the ADC. Leaving signals underscaled effectively “leaves resolution on the table”, but it is also crucial to leave sufficient signal margins to account for tolerances in the signal chain. The figure below shows a correctly scaled signal with plenty of margins to account for noise or error in the signal chain.

Figure 1-3. Example of a Correctly Sized Signal

In terms of resolution, an overscaled signal is far worse than an underscaled one. Overscaled signals are clipped, meaning that the measurement is capped at the maximum value of the ADC, as shown in the following figure.

Figure 1-4. Example of a Clipped Waveform