Signal-to-noise and distortion ratio (SINADR[1]) is a measurement of the purity of a signal. SINADR is typically used in data converter specifications. SINADR is defined as:
where is the average power of the signal, quantization error, random noise and distortion components. SINADR is usually expressed in dB. SINADR is a standard metric for analog-to-digital converter and digital-to-analog converter.
SINADR (in dB) is related to effective number of bits (ENOB) by the following equation: