[hpsdr] processing speed

[Graham / KE9H]

Georg:

The signal coming in from Mercury is a "broadband" signal between
192 kHz width and 48k Hz width, set according to the number
of samples per second.  Perhaps analogous to the "high IF output" in
a traditional heterodyne receiver.

All of what you might call, in a traditional receiver, the "low if 
filtering"
and demodulation is done in the PC.  So it is working a lot harder
is you are throwing more samples at it. You can also adjust the
load on the PC by changing the "Buffer Size" under
Setup->DSP->RX Buffer Size.

There is some discussion of this in the FLEX-5000 manual:
    Chapter 4 - Audio TAB (page 90)
    Chapter 4 - DSP TAB (pages 101 - 102)
    Appendix A (pages 201 - 205)

http://support.flex-radio.com/Downloads.aspx?id=246

--- Graham / KE9H

==

Georg Prinz wrote:
> ***** High Performance Software Defined Radio Discussion List *****
>
> Now my system (computer with amd cpu at 1.7GHz and 3GB Memory) is
> running fine with 92000S/s. It is pleasure, indeed!
>
> But if I am changing to 192000S/s there are dropouts. I call it strobo
> effect. Looking at the cpu load it is about 50 to 55% only. At 92000S/s
> the load drops to 40%.
>
> Can anybody explain me that behavior? I thought that the main processing
> is done on mercury and ozy and the computer is doing the vizualization
> only.
>
> Vy73, 
> Georg, dl2kp
>
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