On 4/4/2018 2:17 PM, Graham wrote:
narrow b/w and robustness are diametrically opposed
I think there are limitations to this though Graham. Our transmitters
are peak-power limited so we can't simply increase the power to overcome
the relatively poor PAPR (Peak to Average Power Ratio) inherent in
wide-band, multi-carrier modems without causing distortion.
Getting the signal high enough above the noise to realize the
performance of such modems seems challenging and it appears to be the
reason why Pactor engineers chose to included narrow-band protocols with
fewer carriers and improved PAPR.
Jose takes a different approach where the PAPR appears to remain
constant. There must be a benefit to this and it must be in the
technique used to improve PAPR. Not sure if that's easier or harder to
do with ODFM modems?