Re: [Discuss-gnuradio] Signal coming from the USRP to the computer

Of course that is true. I just wanted to make sure my understanding of the whole signal flow in GNU Radio/USRP system was right. The IF, down coversion etc stages confused me a bit. I was only interested in what I am getting on the USB bus to work with so, I wanted to make sure my understanding of this system was right.

Thanks for the reply.

On Sun, May 29, 2011 at 4:11 PM, Marcus D. Leech <mleech@ripnet.com> wrote:

On 05/29/2011 04:50 PM, John Andrews wrote:

Hi All,
I want to know what is the signal coming from the USRP onto the USB bus. I know that the received signal is a baseband signal and assuming complex sampling (I have RFX2400 daughterboards) each complex sample that enters the USB bus is the following,

x[i] = (inphase_component) + j (quadrature_component), and
x[i] = m(t)cos( 2*pi*FREQ_OFFSET*t + PHI ) + jm(t)sin( 2*pi*FREQ_OFFSET*t + PHI ), where m(t), is the actual message signal, FREQ_OFFSET is the frequency offset, and PHI is the phase.

Is that correct?

Thanks

More or less, yes.

There will be random noise components as well, since this is "real world", rather than purely a Matlab simulation :-)



--
Marcus Leech
Principal Investigator
Shirleys Bay Radio Astronomy Consortium
http://www.sbrac.org



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