# effective number of bits (ad converter) (ENOB)

The effective number of bits(ENOB) is a characteristic value of A/D converters that characterizes their actual accuracy and performance better than the resolution.

The ENOB value tells how much interference affects the measurement when measuring a known signal. The effective number of bits always corresponds to the actually achieved bit width of an ideal AD converter.

The ENOB value can be derived from the SINAD value, Signal to Noise and Distortion (SINAD), which includes noise and distortion. For a sine wave, 1.76 dB can be subtracted from the SINAD value (dB) to determine the ENOB value, and the result can be divided by the quotient 6.02. For simple rollover calculations, the SINAD value can be divided by a factor of 6.

According to this formula, a 24-bit converter with an assumed SINAD (Signal to Noise and Distortion) of 110 dB has an ENOB of 16.6. This value, which is far from the resolution of 24 bits, has a higher significance in terms of the effective number of bits used.