[aprssig] Rant - Cross platform portability

Gregg Wonderly gregg at wonderly.org
Tue Sep 19 09:52:56 CDT 2006

Dave Baxter wrote:
> It also is not "real time" critical as DSP code would be, and does not
> need any specific hardware IO, like to control a rig etc.  It's purely
> web based.

DSP processing of an AUDIO stream does not have to be done in real time.  The 
audio stream needs to be collected without loss, and the audio hardware, buffers 
and OS drivers do this for you on PC class computers.  You can then just process 
that stream using time sharing software systems.  Look at the SDR-1000.  It is 
software defined radio which is using windows for control of the RF deck.  The 
RF deck converts the RF that you are tuned to, into a 44khz wide audio stream 
through frequency conversion.  That goes into a high quality audio card to 
miminize loss and maximize performance.  But, then everything you hear and 
everything you transmit is processed by a non-real time OS environment.

> Of course, if we start to see 10/100 network ports on
> radio's (as much "High End" test RF equipment from the likes of Agilent
> and R&S is beginning to sport) that would make things a lot easier to do
> with Java.

Java is not just restricted to network communications.  There are various APIs 
for doing serial and parallel port communications as has already been brought up 
in this discussion.  What was at issue in the previous discussion, was the the 
"free" version for windows that Sun had on their web site disappeared.  It can 
still be distributed by those who have it.  Or, the RXTX project can be used, as 
can the commercial packages.

Gregg Wonderly

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