Dear Sir/Madam,
I am working on the NI card Pxi-5660 (NI Pxi-5600 & NI Pxi-5620) and I
would need to understand better how the downconversion and sampling
works:
1) When we configure the card, we set the carrier frequency fc and
bandwidth B to control downconversion. I understand that the band that
we consider is between fc-B/2 and fc+B/2. How is this band
downconverted? (i.e. how do you choose the frequency of local
oscillator? Is it fc-B/2?)
2) Concerning the digitizer. How is the sampling frequency chosen as a
function of fc and B? Does it work at a fixed sampling frequency of
64Ms/s or do you change the sampling frequency as a function of B?
I would appreciate if you can help me on these issues. Thank you very
much in advance.
Best regards,
