RE: [Discuss-gnuradi o] USRP problem ? us ed for Digital beaco n receiver‏

[Wipat phonsukkarn]

Thank you very much Josh

but i have another question for more please

> What frequency did you tune the basic RX? Perhaps you are seeing an
> offset between signal generator and DDC. Do the tones the FFT sink look
> to be in the correct positions?

Did you mean the tune frequency in the basic Rx same with the frequency that i can set in the usrp source block ?

So if the same i set the frequency in the usrp source block(from my understand is nco frequency ) equal 1.5Mhz

and the tones of the FFT sink seem like the product of the multiplication of the input signal(1.5Mhz) and nco signal(1.5Mhz)

and showed only the input signal - nco signal ' s  frequency response and i think it's correct.

and i have another question that is the signal that come from usrp source that show in the scope sink show the I and Q signal but if i connect the usrp source with the FFT sink it's show the frequncy response only one graph So i'm not sure what was the FFT sink show(I and Q , just I or Q only , or I +Q )

thank you very much for yours advice






> > 1. How do everybody set MUX? I tried to read the datasheet but It
> > wasn't make sense for me.So what I do is use the GRC and used the Usrp
> > block so i know that my db BasicRx is on side B RXA and My WBX is on
> > Side A Rx2 but if i want to set mux in the python program how do i do?
> >
>
> This is the code for the grc usrp* blocks:
> You can see how its set in <gnuradio_repo>/grc/grc_gnuradio/usrp/*.py
>
> >
> > 2. I tried to find the signal's phase,so i generated the signal
> > about 1.5M from signal generator (just for test) directly to the Basic
> > Rx Db. So what i expect is the IQ signal that show in the GRC Scope sink
> > would be the constant(cosphi and sinphi) signal but It's not ,the
> > signal seem to be like the cycle(period). What do I misunderstanding?
> >
>
> What frequency did you tune the basic RX? Perhaps you are seeing an
> offset between signal generator and DDC. Do the tones the FFT sink look
> to be in the correct positions?
>
> -Josh
>