Re: [Discuss-gnuradio] OFDM / DAB demodulation

[Jens Elsner]

To resample, I used the Matlab "resample" function

chunk_resamp = resample(chunk, 2048, 2000);

It's basically an FIR low-pass - phase is linear.

I'll try again today without resampling, but then the timing is
pretty much screwed up.

Jens

On Fri, Mar 31, 2006 at 04:28:14PM -0800, Eric Blossom wrote:
> On Fri, Mar 31, 2006 at 05:10:40PM -0500, Clark Pope wrote:
> > I would doubt that unless your USRP is defective. The phase noise should 
> > only become a major factor at baud rates below about 10 kbaud.
> > 
> > What's the actual bandwidth of the DAB signal? Did you try collecting at 4 
> > MSPS and then downsampling to the FFT sample rate? Maybe the CIC or 
> > compensation filter transition are distorting the final result.
> > 
> > -Clark
> > 
> > >>
> > >> DAB is using COFDM with pi/4-DPSK on 1536 subcarriers (see www.etsi.com, 
> > >standard
> > >> EN300401 for details). I wrote some Matlab code to demodulate the
> > >> signal. The data is resampled from 2 MHz (URSP) to 2.048 MHz (DAB 
> > >Standard).
> > >> A frequency offset is compensated manually.
> 
> How did you resample from 2.000MHz to 2.048 MHz?
> 
> Eric