The analog circuitry described in previous chapters includes passive and active electronic components. The datasheet specs show parameters (resistance, capacitance, offsets, bias currents, etc.) as typical values and tolerances. The equations in previous chapters consider typical values. Component tolerances affect DC, AC, and CMMR performances of the Analog Discovery 2. To minimize these effects, the design uses:

• 0.1% resistors and 1% capacitors in all the critical analog signal paths
• Capacitive trimmers for balancing the Scope Input Divider and Gain Selection
• No other mechanical trimmers (as these are big, expensive, unreliable and affected by vibrations, aging, and temperature drifts)
• Software calibration, at manufacturing
• User software calibration, as an option

A software calibration is performed on each device as a part of the manufacturing test. AWG signals are passed to a reference instrument and reference signals are connected to the Scope inputs. A set of measurements is used to identify all the DC errors (Gain, Offset) of each analog stage. Correction (Calibration) parameters are computed and stored in the Calibration Memory, on the Analog Discovery 2 device, as Factory Calibration. The WaveForms software allows the user performing an in-house calibration and overwrite the Calibration Data. Returning to Factory Calibration is always possible.

The WaveForms Software reads the calibration parameters from the connected Analog Discovery 2 and uses them to correct both generated and acquired signals.