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Re: AO-40 data mode




> 3. I don't understand why you think you'd need 3dB more power?  Than what?  
> SSB?  The only disadvantage to digital modes is that silent parts of speech 
> still takes ones and zeros to get across, but on the other hand, the peaks 
> in SSB would be higher.  Averaged out, the FEC'ed digital signal should take 
> less spectrum and power than the SSB voice.  It's mathematical magic, yes, 
> but true.

Many (some?) narrowband voice CODECs perform silence detection and send
no frames during silent periods.  In most applications using digitized
voice, one of the other major factors that's managed is the latency
(which related to frame sizes), and also how sensitive the CODEC is to
delay jitter in the arriving frames.  The jitter issue can be a pain on
a packet-switched network, but on a point-to-point RF links (bent in
the sky or not), the jitter should be essentially zero, with small,
regular changes due to the change propagation path.

louie



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