Re: [Discuss-gnuradio] Questions on the usrp_fft and usrp_oscope

[John Clark]

Sachi wrote:

> Hi, guys
>
> I met some confusions when I tried the usrp_fft and
> usrp_oscope.
>
> I generate a 2MHz, peak to peak 1V, sin wave using the
> Agilent signal generator, and connect it to usrp.
> However, the result of usrp_fft always shows a very
> strong component at DC, besides the 2MHz. Why is that?
>  

As I recall the FT transforms a 'constant' function into a single point 
at the
origin, suggesting that your 2Mhz signal is offset from 'zero', either by
an error in the signal generator setup, or in the analog portion of the
A/D.

(I don't have things setup to test with a known data set... )

John Clark