Re: 400 Mb/s ADC

In article <[EMAIL PROTECTED]>, Jeff Peterson wrote:
> we will take about 64K samples, then can pause while processing...
> however all the time we are pausing we are losing data.  so we do want to
> keep the duty cycle up.  50% duty cyle is not a problem. 5% would be.

It sounds like you *really* want to do the FFTs on PCs, rather than on
an outboard DSP.  (for your application that might make sense, as you're
only building one or a few of these things, and software development
will be hugely easier)  You might try "striping" the data across
multiple PCs.  After the ADC, block the data into 64K "packets", and
have 2 or 3 links to FPGA "NICs" that receive blocks of 64k samples
(plus maybe a sequence number) and DMA them over PCI.

Even if you do try to convert to SCSI or Fibre Channel and use standard
adapters, you might still want to consider the striping idea.

-- 
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 Peter Desnoyers           (617) 661-1979    [EMAIL PROTECTED]
 162 Pleasant St.
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