Question to I and Q routing


#1

Hi All,

i have a signal generator which is only connected to 1 SMA connector
at the LFRX daughterboard.
In the gnuradio documentation is written:
“Each of the 4 ADC’s can be routed to either of I or the Q input
of any of the 4 DDC’s.”

But if i store the data coming from the usrp to disk, i have got
real and imag values, which represents the I and Q values.
So how is the Q part created ?
Or do i have to create it by connect my signal generator to 2 SMA
connectors ?

My test signal is a sine signal.

Regards Markus


#2

On Wed, Apr 01, 2009 at 08:15:47AM +0000, feldmaus wrote:

So how is the Q part created ?
Or do i have to create it by connect my signal generator to 2 SMA connectors ?

My test signal is a sine signal.

Regards Markus

Markus, these are all great questions, but I have the suspicion that
you haven’t studied the USRP FAQ. For starters please read and
understand:

http://gnuradio.org/trac/wiki/UsrpRfxDiagrams
http://gnuradio.org/trac/attachment/wiki/UsrpFAQ/USRP_Documentation.pdf
Euler’s identity
CORDIC

Thanks!
Eric