vivkr
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Dear Sheldon,
This is the setup I used.
Signals:
Fin=701 kHz (Sine) Fs=1024 kHz
FFT Setup/THD Setup:
Window: Rectangular (Coherent sampling used, hence no windowing was needed) Nfft=4096
I see a very clean output spectrum, with the peak signal level around (Fs-Fin). The next spur is -110 dB below this, and the remaining spurs, all of which are clearly visible due to coherent sampling are even lower, typically at -130 dB below the peak.
To plot the FFT, I load the output expression in Waveform Calulator, and then define the FFT expression. For THD, I do exactly the same (same set of output samples, window etc.), and let the calculator find the peak tone by itself. Even when I explicitly provide the location of the peak signal, the result remains the same.
Regards Vivek
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