Re: [Discuss-gnuradio] USRP2 - Many Narrowband

[Matt Ettus]

Ryan Pape wrote:
> All:
>  
> I'm currently trying to extract a relatively small number of 
> narrowband channels out of about 10mhz.  With USRP1, I can get two 
> channels easily by using both sets of DDCs.  In some instances, I can 
> successfully use a filterbank, however at 12.5khz channels, I quickly 
> run out of horsepower if I don't keep the decimation high enough, 
> which does not always let me cover the swath of RF I need. 
>  
> Are there any other possibilities with the new USRP2 hardware to 
> implement more DDCs in the firmware to do more of this work on the 
> USRP side?  Any other thoughts in general?

You could implement more DDCs in the USRP2, but it makes more sense to 
use filterbanks in software.  It may take something more complicated 
than a straight forward filterbank across the whole bandwidth.  You 
might want to do it in a few steps.  For example, do a filterbank to get 
you 16 channels of ~500 kHz apiece, and then do smaller filterbanks on 
only those 500kHz bands have signals of interest in them.

Matt