RE: [Discuss-gnuradio] Unable to tune Tx or Rx with XCVR2450 on USRP2

[Ian Holland]

Thanks Josh

I can now confirm that it is definitely failing to lock. I have noticed
on some rare occasions that it actually does lock. However, as soon as
the USRP2 is power-cycled it goes back to the default behaviour of being
unable to lock.

What can be done to make sure that it will lock? Is this likely to be a
hardware issue specific to our daughtercards, or is there something else
we can do in software to get around it?

Thanks

Ian.

>It could be failing to lock. You may want to watch the debug port on
the 
>usrp2. If the lock detect is failing, it will print out on the serial 
>console. attach a 3.3v level serial port

On 01/28/2010 10:09 PM, Ian Holland wrote:
> Hi Josh
>
>> The xcvr has a high band and a low band, which means there is a gap
in
>> the tunable frequency range for the xcvr. Therefore, the
>> "auto-calculated mid-point frequency" is an invalid frequency for the
>> xcvr. Pick a frequency in the high band or low band range:
>
>> #define LB_FREQ_MIN U2_DOUBLE_TO_FXPT_FREQ(2.3e9)
>> #define LB_FREQ_MAX U2_DOUBLE_TO_FXPT_FREQ(2.6e9)
>> #define HB_FREQ_MIN U2_DOUBLE_TO_FXPT_FREQ(4.8e9)
>> #define HB_FREQ_MAX U2_DOUBLE_TO_FXPT_FREQ(6.1e9)
>
> Thanks - I will keep that in mind when using usrp_siggen.py in future.
>
> However, I have tried 2.4G with the source code from my original post
> (relevant code snippet for Tx tuning just below this paragraph, for
> which successTx is 0 and all frequency properties in TxTuneResult are
> 0), and also with usrp2_fft.py -f 2.4G, after burning the latest
images.
> I still face the same problem that neither the Tx nor the Rx will
tune.
>
> /* try tuning Tx to a test frequency */
> double Fc = 2400000000.0;
> usrp2::tune_result TxTuneResult;
> bool successTx = device->set_tx_center_freq(Fc,&TxTuneResult);