[WriteLog] What's wrong with AFSK? was - 5 bit mystery unraveled

[Doug Faunt N6TQS +1-510-655-8604]

   From: Bill Turner <wrt at dslextreme.com>
   Date: Mon, 01 Mar 2004 03:14:24 -0800

   On Sun, 29 Feb 2004 23:47:51 -0800, Jim Smith wrote:

   >It seems to me that the cognoscenti prefer FSK to AFSK.  I have never 
   >seen any reasons for this preference, probably because I haven't looked 
   >in the right place.  So, what's the problem with just sending AFSK to 
   >the radio, thereby eliminating the need for an AFSK to FSK converter?

   _________________________________________________________

   In summary, FSK is more goof-proof and is recommended for that reason
   alone.

There, unfortunately, are filter select limitations on some radios that
making using FSK desireable for that radio.  

And AFSK has usually been implemented by using software timers in the
computer system, while FSK has usually been implemented with hardware
timing, and given the unpredictability of the most common operating
systems, this has been a factor.  Using bit-banger ports for FSK or an
AFSK to FSK converter lose this safety factor.

73, doug