Forum: GNU Radio Trondeau C++ daughterboard code

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Per Z. (Guest)
on 2008-10-06 20:09
(Received via mailing list)
Dear All,

I am trying to migrate from home-made daughterboard code to the code by
Trondeau. I am using the version 9305. I use  db_flexrf_1800_tx_mimo_b.
After changing "d_common->R_DIV(1)" to "d_common->R_DIV(16)" the signal
is
showing up on my spectrum analyzer at the correct frequency. However,
the
amplitude is about 25dB weaker than when using the home-made
daughterboard
code. I am using the daughterboard code as given by the code fragment
below.
Does anyone have an idea what could be wrong ?


BR/
Per

usrp_standard_tx* tx = usrp_standard_tx::make(0,64,2,47768);
std::vector<db_base_sptr> db_rx0,db_rx1,db_tx0,db_tx1;

db_tx0=tx->db(0);
db_tx1=tx->db(1);


db_tx0[0]->set_lo_offset(tx_lo_offset);
tr=db_tx0[0]->tune(0,carrier_frequency);

db_tx0[0]->set_enable(true);
db_tx0[0]->set_gain(db_tx0[0]->gain_max());
Stefan Brüns (Guest)
on 2008-10-06 21:32
(Received via mailing list)
On Monday 06 October 2008 18:02:29 Per Z. wrote:
> Dear All,
>
> I am trying to migrate from home-made daughterboard code to the code by
> Trondeau. I am using the version 9305. I use  db_flexrf_1800_tx_mimo_b.
> After changing "d_common->R_DIV(1)" to "d_common->R_DIV(16)" the signal is
> showing up on my spectrum analyzer at the correct frequency. However, the
> amplitude is about 25dB weaker than when using the home-made daughterboard
> code. I am using the daughterboard code as given by the code fragment
> below. Does anyone have an idea what could be wrong ?

The DB code sets the gain in the 9862 to the wrong value (there is
something
wrong with the calculation of the register value from the gain in db) -
this
may be fixed in the cppdb feature branch.

Stefan

--
Stefan Brüns  /  Bergstraße 21  /  52062 Aachen
mailto:lurch at gmx.li  http://www.kawo1.rwth-aachen.de/~lurchi/
   phone: +49 241 53809034     mobile: +49 151 50412019
Stefan Brüns (Guest)
on 2008-10-06 22:32
(Received via mailing list)
Attachment: usrp_pga-fix.diff (0 Bytes)
On Monday 06 October 2008 19:31:04 Stefan Brüns wrote:
> The DB code sets the gain in the 9862 to the wrong value (there is
> something wrong with the calculation of the register value from the gain in
> db) - this may be fixed in the cppdb feature branch.

Patch attached.

Stefan
Stefan Brüns (Guest)
on 2008-10-06 22:38
(Received via mailing list)
Attachment: usrp_pga-fix.diff (0 Bytes)
On Monday 06 October 2008 20:30:36 Stefan Brüns wrote:
> On Monday 06 October 2008 19:31:04 Stefan Brüns wrote:
> > The DB code sets the gain in the 9862 to the wrong value (there is
> > something wrong with the calculation of the register value from the gain
> > in db) - this may be fixed in the cppdb feature branch.
>
> Patch attached.
>
> Stefan

Sorry, wrong one, only the last hunk is the correct part.

Attached again.

Stefan
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