SLWU087E november 2013 – june 2023
For the Single FFT test, a number of calculated statistics and AC performance measurements are displayed to the left of the power spectrum display.
SNR - Signal-to-Noise Ratio is the ratio of the power of the fundamental (PS) or input frequency to the noise floor power (PN), excluding the power at DC and the first five harmonics. SNR is either given in units of dBc (dB to carrier) when the absolute power of the fundamental is used as the reference, or dBFS (dB to full scale) when the power of the fundamental is extrapolated to the converter’s full-scale range.
SFDR - Spurious-Free Dynamic Range is ratio of the power of the fundamental to the highest other spectral component (either spur or harmonic). SFDR is typically given in units of dBc (dB to carrier).
THD - Total Harmonic Distortion is the ratio of the power of the fundamental (PS) to the power in the first five harmonics (PD). THD is typically given in data sheets in units of dBc (dB to carrier).
SINAD - Signal-to-Noise and Distortion is the ratio of the power of the fundamental (PS) to the power of all the other spectral components including noise (PN) and distortion (PD), but excluding DC.
ENOB - Effective Number of Bits is a measure of a converter performance as compared to the theoretical limit based on quantization noise.
Fund. – This parameter displays the power level of the fundamental.
Next Spur. - This parameter displays the power level of the next largest spur that is not an HD spur.
HD2-6 – Display the power values of the second through sixth harmonics of the input frequency in dBc.
NSD/Hz – The parameter displays the Noise Spectral Distortion in full scale/Hertz of bandwidth or dBFs/Hz.
M1, M2, Delta – Displays the power level of the location of markers M1 and M2. These markers can be moved around on the spectrum with the mouse. The Delta parameter displays the power difference between M2 and M1.