[Synchrodyne]

There are various other pertinent papers by the BBC, Siemens, and others, not all on the web, but going there I think would pull the thread too far off-topic. By way of an overview, one could say that adding subcarriers to a system that had been developed and optimized for high quality mono transmission and reception without increasing the allowed maximum deviation was going to involve some non-negligible loss of performance as measured along several vectors howsoever it was done. Different systems varied the performance loss distribution amongst the individual vectors, but did not obviate the overall loss. The FCC chose the Zenith-GE system as the best compromise back in 1961 (in fact it merged the separate Zenith and GE proposals into one system.) Then in the 1960s, Europe chose the same system; in that case there might have been some extra weighting given to it on the basis that it was established in the Americas and elsewhere, such that any other contender would have had to be noticeably better rather than just directionally or selectively so in order to prevail.


Cheers,