Unless on what you were working on it had a different meaning, MSK means "Minimal Shift Keying". It is still a PSK modulation of any order, however the transition between significant phase locations is not instantaneous, but, shaped in various ways to smooth the transition. This results in a waveform that has a minimal AM component which then consequently reduces spectral regrowth when amplified by a non-linear amplifier. Allows for closer channel spacing, and is generally nicer, at the expense of additional complexity. 73 - Mike
Mike B. Feher, EOZ Inc. 89 Arnold Blvd. Howell, NJ, 07731 732-886-5960 office 908-902-3831 cell -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Kenneth G. Gordon Sent: Sunday, August 10, 2014 12:27 PM To: paul swed; [email protected] Subject: Re: [time-nuts] VLF Phase-tracking receivers. On 10 Aug 2014 at 6:24, paul swed wrote: Hello again, Paul. Thanks for replying. Please see below. > On iPhone > Yes but those stations are fsk so the offsets an issue. As I understand it from back in the 1970s when I was first working on this sort of thing, the modulation is not FSK, but "MSK" (whatever that is) at something like 25 to 50 Hz, and the Navy installed the necessary equipment in the 1970 time-frame to assure that the transmitted signals are phase-stable. The same thing, apparently holds true for GBR and some of the other stations like those. Russian, for instance. I have no idea what, exactly, has occurred in this area since then though. > We may assume the transmitter is accurate. Yes. > But how accurate? That is a good question. I have no idea at this point. I'll try to find out. > Then the fsk generator Well, as I said above, it is not FSK....exactly... I DO know that the Navy had problems when they first tried FSK with their antenna tuning methods. Due to the extremely hi "Q" of their antenna systems, any useable frequency shift (at the receiver) was so great that it pretty much threw their antennas out of tune on either mark or space. Thus, they had to use a different method. I never did learn what that method was. Perhaps now is the time for me to find out. Thanks again, Ken W7EKB _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
