RE: [digitalradio] Sub Channel DQPSK

2007-10-27 Thread John Bradley
For what it's worth Rud, PSK31 appears much more susceptible to phase distortion that wider modes such as MFSK and OLIVIA. Here, we are just over 50 degrees north latitude and have many more occasions to experience the Northern flutter from the aurora. This phase distortion knocks out PSK31

Re: [digitalradio] Sub Channel DQPSK

2007-10-27 Thread Jose A. Amador
Of course it is. PSK31 goes raw, while MFSK and Olivia have FEC added. So, stand a better chance of being decoded correctly. When nature starts stirring the gas above, all it reflects (refracts) suffers the same effect as it had passed thru the house of mirrors, making giants look like dwarfs

[digitalradio] Sub Channel DQPSK

2007-10-26 Thread Rud Merriam
Would the phase distortion that can corrupt a PSK signal occur the same on a M-PSK signal? If the phase distortion affects all the sub channels then doing differential PSK among the sub channels would work where symbol to symbol DxPSK would not work. Rud Merriam K5RUD ARES AEC Montgomery

Re: [digitalradio] Sub Channel DQPSK

2007-10-26 Thread Jose A. Amador
Rud, You can see the variations in the ionosphere as a phase modulator embedded in the channel. So, it will phase modulate whatever you attempt to get thru it. Actually, it has a phase modulator embedded for each arriving path. With differential encoding, and signalling speed higher than the