SINAD to ENOB Calculator

Effective Number of Bits (ENOB) is a measure of the dynamic range of an analog-to-digital converter (ADC), digital-to-analog converter (DAC), or any other circuitry associated with them. The resolution of an ADC is typically specified by the number of bits used to represent the analog value of a signal. But practical circuits inevitably introduce some amount of noise and distortion. These distortions may be due to the nonlinearity of electronic components followed by other thermal effects. Therefore, the resulting signal contains both noise and distortion, along with the desired signal. This imperfection reduces the number of bits of accuracy in an ADC.

ENOB represents the effective number of bits or the reduced number of bits of accuracy in an ADC. For example, an ADC may have a resolution of 16 bits, but the effective number of bits may be only 11.

Signal to Noise and Distortion Ratio (SINAD) is a measure of the quality of a signal received by a system. The SINAD is defined as,

Where Psignal is the average power of the signal to be decoded,

Pnoise is the average noise power, and

Pdisortion is the average distortion power.

SINAD can also be thought of as a quantitative measure of the receiver sensitivity i.e. the lowest signal strength that the receiver can detect.

Knowing the level with which the analog signal has been corrupted by noise and distortion in comparison to the effective number of bits of accuracy in the digital domain provides a clear perspective of the performance of the system in both analog and digital domains, and the relationship between them. The following formula is used to calculate the effective number of bits (ENOB) for a given signal-to-noise and distortion ratio (SINAD):