hi
I have a problem in using the 5620 digitizer to fetch real time data
We have a project to demodulate GPS signal wich center frequency at 1.57542GHz and bandwidth 2MHz.
In first step, I used " ni5660 fetch IQ data.vi" by modify the
bandwidth to be 2MHz and fetched about 0.2 second data. I succesfully
demodulated the GPS signal.
But I found with this vi, I can not get longer time, for example,
60seconds data. So I used the "nituner getting started.vi" to
mannually downconverte the signal to IF and "use niScope EX Stream to
Disk.vi" to fetch the data to disk. Now the niTunner: frequency
shift 1.561GHz.
So, the IF frequency is 1.57542GHz-1.561GHz=14.42MHz. Then I set the
digitizer frequency to 6.4M/s which means that the the signal is
aliased to 14.42MHz-6.4MHz*2=1.62MHz. With the signal bandwidth
2MHz. Now the aliased signal is from 1.62MHz-1MHz to
1.62MHz+1MHz. But now, I can not demodulate this signal !!!
Could anybody help me about this?
Thanks
