[hpsdr] Atlas based HPSDR PureSignal

[Georg Prinz]

Hi Phil,

actually, in Atlas based systems there is an Alex transmit board with a
RF power directional coupler installed. These dc voltages from the
coupler provided at the 4-pin connector, could they be used for
predistortion? Or do we need an additional coupler when all the
modifications you described are done?

72, Georg, dl2kp



 



Am Mittwoch, den 29.01.2014, 10:17 +0800 schrieb Phil Harman:
> ***** High Performance Software Defined Radio Discussion List *****
> 
> Hi Bruce,
> 
> Is possible.  We would need to add the Tx modifications to Penny. Since
> that is a change to add a cFIR and modified CIC interpolator that should
> not be an issue.
> 
> We also need to implement a full DDC in order to feed back the data being
> fed to the DAC.
> 
> Since the DDC is always on the same frequency as the Tx we can use the
> same CORDIC for both Tx and Rx which will save some LUs.
> 
> We may run into FPGA size issues here.
> 
> The Atlas bus does allow for 4 receivers and the current Mercury code
> implements 3 so we are OK there.
> 
> The Mercury code will need to be modified to use the new FIRs but the FPGA
> has spare room so I think that should fit OK.
> 
> The other issue is the phase relationship between the DAC feedback and RF
> feedback may not be consistent.  I had that issue with the VNA code and
> solved it by sending the same phase word, rather than frequency, to the Tx
> and Rx CORDICs.
> 
> If that is an issue we could always calculate the phase word in Metis and
> sent it to Mercury and Penny over the Atlas bus.
> 
> I can't work on this at the moment since up to my eyes with other things
> but perhaps an interesting 'weekender' project for someone?
> 
> 73 Phil...VK6PH
> 
> 
> > ***** High Performance Software Defined Radio Discussion List *****
> >
> >
> > Will the PureSignal software be available for the HPSDR ?
> >
> >
> > 73's , Bruce
> >
> > KL7JDR-KL7SDR
> >
> > Bruce W. Mills
> > P.O. Box 1500
> > 31490 Echo Lake Road
> > Soldotna , Alaska
> >    99669
> >
> > (907)262-4373 Home
> > (907)398-4595 Cell
> >
> > kl7jdr at alaska.net
> >
> >
> >
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