Problem to set RF filter on DBSRX board

GNU Radio
1

Hi,
I’m a new user on this forum…
I need some help and I hope someone can save me from the madness %-|%-|
I used on USRP 1 the DBSRX daughterboard with discrete success to
acquire
DVB-T signal in 800 MHz band.
Now i want to carry on my work on USRP2 to avoid problem with overrun
but…after hardware changes at daughterboard it works very well to see
the
signal but I can’t set daughterboard RF filter bandwidth to select a
particular DVB- T channel cause in USRP2 there is no method “set_bw()”.
Now…I can modify db_dbsrx.c to add this method that modify registers
to
set RF frequency bw like the same “.cc” script for USRP1…but after
that? I
have to recompile something after that? how can I recall “my” new method
in
a python flow graph if the usrp2 class not contain this new method?

Please help me…and I’m deeply sorry if someone thinks I’m an ignorant
:confused:

Thanks,
Domenico

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2

Domenico,

Here’s the deal your daughter board is probably suffering from low
impedance which is what is causing the DVB -T Channel to have the wrong
radio frequency. if you really want it to work correctly then what you
will have to do is replace the rf filter with one that works correctly
you can see a list of rf filters here
http://www.oscilent.com/catalog/Category/rf_saw_filter.htm let me know
if this works properly for you. You also may want to check to see if the
diagnostic tool is functioning properly.

Now i want to carry on my work on USRP2 to avoid problem with overrun
but…after hardware changes at daughterboard it works very well to see
the
signal but I can’t set daughterboard RF filter bandwidth to select a
particular DVB- T channel cause in USRP2 there is no method “set_bw()”.
Now…I can modify db_dbsrx.c to add this method that modify registers
to
set RF frequency bw like the same “.cc” script for USRP1…but after
that?