SINAD Measurements
The SINAD has been measured using a R&S SML-001. As explained in this tutorial , some spurs may appear on the FFT of the measurements. These spikes are actually due to the oscillator and not the ADC. Figure 1 shows the results of the FFT (average of 500 measurements on 1024 points, windowed with a Hanning windowing function).
Figure 1 - SINAD measurement without filter
To avoid these harmonics to falsify the measurement, we filtered the generator output with a 15 MHz LPF (Minicircuit SLP-15+). The result is plotted in figure 2.
Figure 2 - SINAD measurement with the 15 MHz filter
The SINAD is estimated to 70.4 dB. And the ENOB is esitmated to 11.4 bit (by using the following equation).
ENOB = (SINAD - 1.76)/6.02
17th of January 2017 - Nicolas Boucquey