[hpsdr] computer performance

[Chris Albertson]

--- FRANCIS CARCIA <carcia at sbcglobal.net> wrote:

> ***** High Performance Software Defined Radio Discussion List *****
> 
> > Hi All,
>   I wonder if I was fooling myself thinking I could make a USB2 PCI
> board function as a good interface for HPSDR. I wonder what kind of
> machine will be required when the next cards come on line. I'm told
> 500 meg of ram isn't enough to run the XP pig with big applications.
>   Any suggestions so I only have to upgrade once? frank 

First off you should be able to find an SDR project that
will work with any computer you might happen to have.  Even
some old "junker" you scrounge up.  Seeing as you get to
pick the project you control what computer you use.

Looking the other way.  People designing SDR front ends will 
likey design them to use whatever computer interface is
common.  Notice people are using USB and Ethernet now and
we don't see any parallel port designs.  The trend will
continue so you don't have to worry.

In general, getting the data into a PC is the hardest job with SDR.
If you are willing to accept a narrow bandwidth a sound card works.
USB and 1000BaseT can do more.  But if you want to bring output from
a pair of ultr-fast 16-bit ADCs into a computer it will not be easy
or inexpensive.

I think the "real solution" comes from the old doctor joke that
goes "Doc, it hurts when I do this. Doc replies, Then don't do that"
Applied to SDR the best thing is to move the digital processor
inside the radio. In other words "don't do the high bandwidth
interface."  Processors are so cheap that it's best to put the
FFT and FFT-1 in the hardware and bring only the demodulated
signal(s) out.  Save the PC for control and display.

The most "future proof" computer I can think of right now is the
Apple Mac Pro.  It can run every common OS (Mac OS X, Windows XP,
Linux, Solars,...) it has all the common interfaces built in,
has up to 8 CPU cores and 16GB RAM and the price is very good for
what you get. 

That said, I don't beleive in "future proof" it is best to wait
until you need a computer and then buy it right then.  Never buy in
advance of need and wait.


Chris Albertson
  Home:   310-376-1029  chrisalbertson90278 at yahoo.com
  Office: 310-336-5189  Christopher.J.Albertson at aero.org


       
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