[hpsdr] Metis functionality

[Alberto I2PHD]

On 5/16/2011 4:00 PM, Jeremy McDermond wrote:
> 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.
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
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
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
many different anti-alias FIR filters, but these can be easily downloaded on-the-fly to the FPGA.
Ozy has hardware limitations that prevent those high data rates, but hopefully Metis should be better in this respect...

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,
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.

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
programming, otherwise I would implement myself that capability... :-(

-- 
/*73 Alberto I2PHD*/
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