Hi Mark,

the reason while it works is that the carriers are equispaced, so f2-f1 = f3-f2 = 40 Hz. So the whole pattern is repeating every 25 ms. Every time when f1 and f3 are in phase, f2 is now in quadrature. 

This three carrier scheme is the simplest form of a quadratic phase, forming a rudimantary chirp. For a large number of equispaced carriers, the waveform will asymptotically approach a perfect sweep, like in chirp radar. I have also employed it to reduce PEP in my "chirped hell" multitone picture transmission mode.   

Unfortunately it usually won't work for OFDM because each subcarrier is independently modulated, typically in both amplitude and phase. This will destroy the beneficial phasing and lead to the usual quasi-Gaussian amplitude statistics.

Best 73,
Markus

-----Ursprüngliche Mitteilung-----
Von: gm4ism <[email protected]>
An: markusvester <[email protected]>
Verschickt: Sa, 28. Okt 2017 13:40
Betreff: 3 carrier peak volts