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On 5/16/2011 4:00 PM, Jeremy McDermond wrote:
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cite="mid:D81B67E7-DADB-464F-AC1A-5531679CA3E2@xenotropic.com"
type="cite">
<pre wrap="">The current FPGA code only allows three choices of sample rates, which determine the FIR used as well: 192000, 96000, 48000. The FIR is equal to the sample rate. This isn't to say it's set in stone. That's why there's an FPGA, so that we can modify these values as we learn more by experimentation.
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Isn't this a bit limited ? Look at what the market offers...
Perseus can send to the PC up to 2 MHz of sampled data, the Qs1r has
been <br>
successfully tested by Phil C. with Winrad with a bandwidth of 4
MHz... a sampling rate of max 192 kHz is not very much.... IMHO
there <br>
should be in the FPGA a programmable downsampler that gives the user
the choice of the final data rate. I know, this would imply to have<br>
many different anti-alias FIR filters, but these can be easily
downloaded on-the-fly to the FPGA.<br>
Ozy has hardware limitations that prevent those high data rates, but
hopefully Metis should be better in this respect... <br>
<br>
The holy grail of the MWLs is the capability of recording to disk
the I/Q data of the entire MW band, overnight, to be then able, with
leisure,<br>
to check the day after which stations were present, checking at top
of the hours their ID... and this capability needs a bandwidth of
2MHz.<br>
<br>
I know, the HPSDR is not especially meant for MWLs, but rather for
experimenters, and I just am too sorry to know very little of FPGA<br>
programming, otherwise I would implement myself that capability...
<span class="moz-smiley-s2"><span> :-( </span></span><br>
<br>
<div class="moz-signature">-- <br>
<i><b>73 Alberto I2PHD</b></i>
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