RE: [Discuss-gnuradio] DAB receiver

[Ravishankar. M]

Hello Andreas,

  Sampling rate is 2.048Msps. When I analyze every DAB frame captured, I see
that in total the whole frame has shortage of 9 to 10 samples. There could
be a very high possibility due to ADC clock drift when we capture the data
from DAB generator and digitize it. 

  Thanks for the references. I have developed the receiver side matlab code
which works for simulated data. But I face issues in getting it working for
real time streams. I need to add sampling rate converter in the code which I
will be doing. You have mentioned in your thesis.pdf that you did refer to a
matlab code for DAB receiver. If possible and if it's not copyrighted can
you share the same to me?

Best Regards
Ravi

-----Original Message-----
From: address@hidden
[mailto:address@hidden
On Behalf Of Andreas Mueller
Sent: Wednesday, May 27, 2009 12:11 AM
To: address@hidden
Subject: Re: [Discuss-gnuradio] DAB receiver

Hello Ravi

Ravi Trivedi wrote:
> Hello all,
> 
>   I am trying to implement synchronization of DAB receiver in matlab. I 
> have been facing some problems when I test the matlab receiver code for 
> real time streams.
>   First issue is sampling rate estimation problem. I see that real time 
> frame has shortage of samples when compared to values given in 
> specification. I do frame detection first followed by joint estimation 

What is your sampling rate, and how many samples are you missing? It's
likely that your sampling rate is not exactly what you expect, when you
use real-world data, and maybe you have to do sampling rate correction
as well.

> of fine timing and coarse frequency offset. After compensation, I 
> perform fine frequency offset estimation and compensation. I see that 
> for real time streams FIC decoder doesn't pass the CRC. If I use 
> simulated data CRC check gets passed.
>   Does anyone have receiver matlab code working for real time data which 
> I can use for comparison with my code? Thanks in advance.

I did an implementation for GNU Radio a while ago. You can find it at
[1] and a description in [2]. Although it's not complete, it does
everything on the lower levels, up to (and including) FIC CRC
verification (which works, also with real-world data).

Regards, Andreas

[1] http://people.ee.ethz.ch/~andrmuel/files/gnuradio/gr-dab.tgz
[2] http://people.ee.ethz.ch/~andrmuel/files/gnuradio/dab-doc/thesis.pdf