Re: [Discuss-gnuradio] Bypassing the interpolation

[Cheaw Wen Guey]

Hi Jeff,

I read about another guy trying to implement something similar and
Jonathan Corgan advised using the USRP2 due to the ability to send and
receive on time as well as having extra FPGA space to implement any mods
to the system. I am however lost as to where to begin. I suppose the
software route will be the easier path but lacking any examples or
pointers after searching through the net has brought me here.

Thanks.

<quote>
Hello,

I am working on a similar project to use a USRP 1 as a RADAR device for
a temperature measurement application.  I am not sure about the USRP2,
but for USRP1 it is possible to send a signal from the FPGA to the DACs
without interpolation through manipulation of the FPGA registers and by
using custom verilog code.  The most relevant example would be
usrp_radar_mono.  I am not sure if there is similar code for the USRP2.

~Jeff

On 8/2/2010 10:59 AM, Cheaw Wen Guey wrote:
> Hi,
>
> I think I may not be the first to ask this but here is my problem.
>
> I am designing a radar receiver using a USRP2. My transmits and receives
> are done in pulses. The problem is that I require 80MHz bandwidth and the
> USRP2 can only reach 25MHz. I understand that this is due to to the
> limitation of the GB ethernet. I would like to bypass the DDC and then
> make it not real time to allow the data to be transmitted as I do not
> require the system to be realtime.
>
> My questions are:
>
> 1) Where should I be looking, in the VHDL or the USRP2 firmware to modify
> to allow full bypass?
>
> and
>
> 2) I am still trying to understand how to receive on time. Any examples to
> refer to?
>
>
> Cheaw Wen Guey
> Research Officer
>
>--
~Jeffrey Lambert, K1VZX

-- 
~Jeffrey Lambert, K1VZX



Cheaw Wen Guey
Research Officer