Radar mono

thank you for your replying and your answers, so as i said before i
work with the software: ./usrp_radar.py and i use a USRP Card to
realise a dualstatic radar.
the Command is:./usrp_radar_mono.py -T A -R B -f 2.41e09 --ton=300e-09

–tlook=12e-06 --prf=10000 -v -F /home/naoufel/data.bin -w 16e6
i use a Chirp of 300 ns for the emission but when i visualise saved
echos i see that the prf changes when going from one cycle to another
one , which make my sytem non coherent because and leeds to a phase
changing from one prf value to another.

so my questions are:

  1. is that the PC which gives the order to start Ton and Tlook for each
    cycle of prf or is it charging these parameters in the FPGA and then
    the FPGA which starts Ton and Tlook each time?

  2. if the prf is sent by the PC, is the emission time of Ton is so
    short and not enough to be commanded by another PC and what are the
    limits to stay Coherent from one cycle to another one.

Thank for any kind of help since my non coherent sysytem block my work
and i need these informations to find a solution and going forward in
my Project.

Naoufel AMRI


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On Mon, Aug 25, 2008 at 4:35 AM, Naoufel A. [email protected] wrote:

./usrp_radar_mono.py -T A -R B -f 2.41e09 --ton=300e-09
–tlook=12e-06 --prf=10000 -v -F /home/naoufel/data.bin -w 16e6

The value on Ton is rather low for your chirp width. You are trying
to sweep 16 MHz over 20 USRP clock cycles.

Also, your look time is too long for your PRF. A 12us look time
results in 768 samples in the echo return vector, or 3072 bytes. At a
PRF of 10000, this results in 30.72 Mb/s of data, which likely exceeds
your disk recording capacity. You’re probably getting overruns which
result in gaps in your data.

Johnathan C.
Corgan Enterprises LLC