Re: [Discuss-gnuradio] using sig_source_c on a USRP2

[Brian Padalino]

On Sun, Feb 21, 2010 at 1:13 PM, Charles Brain <address@hidden> wrote:
> Hello,
>
> I have been playing around with the USRP2, mainly to get a feeling for how
> much data I can pass across the Ethernet.
>
> I have noticed something odd
>
> When I use sig_source_c with a sample rate of 20 Ms/s
> and a frequency of 1 MHz with the WBX board set to 1 GHz and the
> interpolation set to 20 I would have expected the output on the HP 8592L to
> be at 1.001 GHz but it is at 1 GHz. I have tried various
> combinations of sample rate and frequency and can make
> little sense of what is happening.
>
> When I use the audio sink and use sig_source_f it works exactly how I
> expected.
>
> What am I doing wrong ?

You should definitely be able to see something at 1.001GHz, but any
residual DC offset will also cause a spike at 1.000GHz when using a
vector modulator.

What's your resolution bandwidth set at on your spectrum analyzer?
Can you post a link to a screen shot or two?

Brian