Table 4.

Combined standard uncertainty for voltage measurement by the ADC component.

Source	Value (V)	Type	Probability Distribution	Standard Uncertainty (V)
Quantization error a	3 × 10−4	B	Rectangular	1.7 × 10−4
Signal to distortion ratio b	2 × 10−4	B	Rectangular	1.2 × 10−4
Repeatability c	1.5 × 10−4	A	Normal	1.5 × 10−4
Combined standard uncertainty, uCount				2.5 × 10−4

^a ±0.5 LSB (least significant bit) Analog Devices AD7490 12-bit ADC resolution 0.6 mV BL⁻¹; ^b 74 dB; ^c experimental standard deviation of the mean of 30 independent measurements of five constant voltages.