Understanding ENOB (Effective Number of Bits) in ADCs: Key Metrics for Dynamic Performance of Digitizing Instruments

Oscilloscope datasheets include many specifications that affect the accuracy of a measurement -- such as the nominal number of bits in the ADC, accuracy specifications, jitter and noise. Effective number of bits (ENOB) is a figure of merit for ADCs, digitizers and oscilloscopes that captures most of the errors caused by acquiring a signal, including impairments like random noise, sample jitter and non-linearity. This application note explains the theoretical basis for ENOB and how it is measured.