spurious-free dynamic range (SFDR)

The acronym SFDR, Spurious-Free Dynamic Range, stands for spurious-free dynamic range and is used to indicate the freedom from distortion of operational amplifiers( OpAmp) and digitizers such as D/A converters and A/D converters.

The SFDR value is important for detecting the smallest low level signals generated by digitizers themselves.

Noise-free dynamic range is the ratio of the root-mean-square( RMS) value of the carrier amplitude to the RMS value of the next largest harmonic at the output of a converter. The spurious-free dynamic range is usually expressed in decibels carrier( dBc), where the letter "c" stands for the carrier frequency, or in decibels full scale( dBFS), which refers to the full scale range of the transducer.

The SFDR value is determined by inputting a pure sine wave into the digitizer to be measured, which is then analyzed for noise and harmonics by means of an FFT transformation.