[hpsdr] Mercury Workings

[Graham / KE9H]

Tim:

There are no "traditional" band pass filters in Mercury, in the sense
lf LC or crystal filters.  The filtering is implemented in software as
digital filters.  Both in the Mercury FPGA and the PowerSDR software in
your PC.  Since they are virtual filters implemented as mathematics,
the filter performance is likely better than anything you have ever used
before, and better than you could afford to buy in a conventional filter.

As long as the front end A->D converter is not in overload, the
software filters can take care of everything else.  Overload will occur
somewhere around 50 milliVolts input with the pre-amp turned on, and
about 0.5 Volts with the preamp turned off.

--- Graham



Tim O'Rourke wrote:
> ***** High Performance Software Defined Radio Discussion List *****
>
> Just a general question if someone on list gets a free couple of minutes Hi Hi!
> How does Mercury handle rejection of out of band signals? I noticed when tuning from ham bands to general coverage the signal level increases, right at edge of band. I am waiting for manual and just curious as I do not see traditional bp filters in block diagram. My guess it is all done with digital filtering. However it works it seems to working FB!
> Keep the faith and tnx for all the work you do to keep us old geisers interest up! 
> Tim W4YN
>
> Tim O'Rourke 
> W4YN at ARRL.Net
> Low Power Amateur Radio Rocks 
> Member of Flying Pigs,ARCI,GQRP,RSGB,ARRL Life Member
> NHRA Life Member
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