[USRP-users] Questions about AGC & low pass filters of USRP FPGA

Josh Blum josh at ettus.com
Sun Jun 17 17:39:34 EDT 2012

> 2) I know that the FPGA's of the USRP's use low pass filters in decimation
> and interpolation. But, specifically, what low pass filters do they use?

The DDC and DUC chain uses half band filters and CIC. When even
decimations/interpolations are selected, a half band filter will be the
last element in the DSP chain.

> 3) I have found some documentation on USRP FPGA ("USRP FPGA Under 1.5x"
> (Firas A. Hamza) & "USRP FPGA Tutorial-4" (Dawei Shen)). But they focus
> mostly on USRP1. Where can I find the detailed information about the latest
> N series USRP's & the daughterboards?

Perhaps you can find more information here:


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