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RE: DSP based High Speed Data



> Basic? Say what?
> 
> DSP is all about brute MIPS number crunching. A Basic interpreter
> would be a colossal waste of time and money.

Who says it has to be an interpreter?  BASIC can be compiled.  Granted, the
code won't be as compact, and it is likely to be a bit slower than the
assembled equivalent, but might be a help to some beginners.

> One of the better environments for DSP hacking is still a PC
> with a sound card. You get useful OS support, development
> tools, and it tracks satellites too. If you're reading
> this message you have a PC, or access to one. Have you
> priced sound cards lately? The last one I bought cost me
> less than $CDN 20.00. It does packet, SSTV, PSK31, weather
> satellites, and plays MP3s too. What's *your* excuse?

My sound card was A$25 a year or so ago, and much the same story, I'm using
it for packet, PSK31, and have plans to add other modes when the downloading
bug hits me.  Actually, are there any good references on programming the
soundcard? (actually, I need a Windows programming for dummies, as my
programming expertise got left behind in the DOS days).

> One issue that was raised earlier (Hi Ulf!) was the tradeoff
> between analogue and digital data demodulation. At the current
> amateur state of the art we have 9600 baud easily handled
> in sound cards and DS eval board. The next step up for amateur

There are a number of examples of 9600, including the Linux kernel and
SV2AGW Packet Engine.  I don't know how well the 9600 implementations work,
but 1200 works very well.

> satellites is P3D's 153.6 kbps downlink, which is far beyond
> the capability of any DSP I can afford. The obvious - and
> completely appropriate - solution is a hardware modem, with
> the HDLC stream processed by software.

I think hardware is the most feasible option... at this time.  But that will
change soon, I suspect.
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