Re: [Discuss-gnuradio] Sample rate for source_noise and source_vector

[Eric Blossom]

On Fri, Oct 27, 2006 at 09:23:19PM +0200, De Lima Julian wrote:
> So I tested but I have another question.
> I read that the data through the USB cable (from computer to USRP) are in the 
> format I/Q complex. (Dawei Shen tutorial)
> 
> My interpolation factor is 512, so the sample rate is 128M/512 = 250kSample/s
> 
> I have a data list with 500e3 data. 250e3 are of 1000uV and 250e3 are of 0uV. 
> I see with my spectrum analyzer during 1 second some power and during another 
> second nothing.
> 
> With a vector_source in complex, no problem. But if I specify a vector_source 
> in short, during 0.5 second I see power and during another 0.5 second 
> nothing. So there is a factor of 2 between the complex and short format.
> 
> Therefore with a vector_list in short the sampling rate is doubled? Because 
> in I/Q format there are 16bits * 2 (I & Q) and in short only 16bits?
> 
> Is it true that when we have a source in short the sampling rate is double 
> because we do not use the I/Q format?
> 
> Thanks
> 
> Julian De Lima

I recommend that you don't use the short interface to the usrp.

Eric