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Re: [Discuss-gnuradio] Sample rate for source_noise and source_vector
From: |
Eric Blossom |
Subject: |
Re: [Discuss-gnuradio] Sample rate for source_noise and source_vector |
Date: |
Fri, 27 Oct 2006 15:13:50 -0700 |
User-agent: |
Mutt/1.5.9i |
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