Tim Pearce wrote:
There is no frequency which can be received by both the BasicRX and
the DBSRX. What frequency are you putting in? What frequency are
you telling the USRP2s to tune to?
Matt
Hi,
Sorry I probably confused things by mentioning the BasicRX
DBSRX is the only receiver we have 2 of at the moment so I was testing
with a 2 GHz Sine wave, tuning the USRP2 to 2GHz and setting decim to 50.
The problem was seen on both usrp2's after enabling the 10MHz ref lock.
When you lock the reference of the USRP2, it will be exactly on 2 GHz.
So if you put in a 2 GHz sine wave which is also locked to the same
reference or locked to something very close, it will also be at exactly
2 GHz. Thus, when it is downconverted to baseband, it will be at DC,
and will be removed by the DC offset correction. Everything is
functioning exactly as it should.
Before enabling the ref lock the sine wave appeared on the oscilloscope
as expected.
That is because without the ref lock you will have some frequency error,
and the signal won't be on exactly 2 GHz.
I tried one USRP2 with the BasicRX just to check the same problem was
appearing -- a 25MHz and 150MHz signal were tested (same decim and
tuning to the frequency the sig gen is generating on). Both frequencies
looked correct on the scope sink until the program was run with the
clock locked to the reference in. - the symptom was slightly different
(appearing as a DC signal rather than noise) which is why I mentioned.
The BasicRX has no DC offset correction, so you will see a DC level,
which is exactly what you are asking for.
I think that what you really want is to tune the USRP2 and the sig gen
to different frequencies.
Matt
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