Re: [Discuss-gnuradio] synchronization questions

[science quest]

Lin,
         Thanks for the reply
I am a newbie  in the practical implementation world

On the daughterboards, there is no synchonization processing.
Everything is made in gnuradio software. You may use 'soft PLL' or
'soft baseband SYNC'.

The daughterboard(FLEX 2400) has a PLL with frequency synthesizer.  I think this is used for frequency synchronization and although I am not sure,but, there should be some way to change its frequency/phase on the fly. May be Marc or Eric can tell us more about this.

With the development of full-digital receiver, now the baseband frequency synchronization is already used in products.

Can you please give one example of such a commercial product.

I'm not familiar with RF/IF. In my opinion, two stages are better. But only one stage is also acceptable. It depends on the signal characters. 

can you please explain why two stages are better and where are they implemented- in RF front end or both in Baseband only. More over, if only one stage is acceptable, where is it implemented- in RF front end or baseband.

My questions are targetted towards typical receiver architectures as used in commercial products so that I can qualify the benefits involved in purely software implementations.

Thanks once again
SQ

On 1/14/07, Lin HUANG On the daughterboards, there is no synchonization processing. Everything is made in gnuradio software. You may use 'soft PLL' or 'soft baseband SYNC'.l<address@hidden> wrote:

2007/1/15, science quest <address@hidden>:

Hi
    My appologies if the question is too vague or sounds naive-
 I have read a number of papers(specially IEEE communication society journals) on synchronization issues in communication- frequency, time and phase sync. All these papers address the issue of synchronization in baseband and no reference is made to the AFC present in transciever chips (which in all probablity is controlled by baseband processor according to some algorithm) . On the other hand literature from receiver circuit perspective present approaches for synchronization in hardware by using AFC/PLL etc and this is performed  on RF signal. Considering this, I have the following questions-
1) Is the baseband approach of frequency synchronization only of theroretical interest or are they actually used in products

 

With the development of full-digital receiver, now the baseband frequency synchronization is already used in products.

2) Is the synchronization task perfomed in two stages? eg- first at RF/IF level and then remaining offset in baseband software

 

I'm not familiar with RF/IF. In my opinion, two stages are better. But only one stage is also acceptable. It depends on the signal characters.  

3) How is synchronization achieved in USRP- at daughterboard hardware or  gnuradio software

 

On the daughterboards, there is no synchonization processing. Everything is made in gnuradio software. You may use 'soft PLL' or 'soft baseband SYNC'.

 

Thanks
SQ



_______________________________________________
Discuss-gnuradio mailing list
address@hidden
http://lists.gnu.org/mailman/listinfo/discuss-gnuradio