On Jan 10, 2011, at 3:35 PM, Wayne Burdick wrote: > The effect on transmission bandwidth is negligible, and it's also extremely > unlikely to affect copy.
Hank W6SX had written to ask me for a rough guess of transmission bandwidth when there is a 1 dB difference in level between mark and space carriers. A rough guess turned out to be relatively easy and the bottom line is that the far off QRM is only about 10 dB down from a phase NON-continuous case of FSK generation, if the mark and space signals are different by 1 dB. Basically, about 10 dB down from the first plot in this web page: http://homepage.mac.com/chen/Technical/FSK/Sidebands/sidebands.html The ideal FSK phase continuous signal should look like the second plot on that page. So, forget about phase noise! Your FSK keying sidebands are going to be a much bigger problem for your nearby neighbors :-). I think that a judicious choice of tone pairs could help, but it is a band-aid, not a technical solution. 73 Chen, W7AY ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
