There is a Wiki article on Costas Loops that includes block diagrams. There are books about the loop filter design.
Signal squaring is simply the Trig identity: Sin(A)**2 = 1/2*[1 - cos(2*A)] which has a DC term and a double frequency term. Sine is symmetriv about the 0 axis. In practice, with low S/N the Costas Loop is probably better. -John ================== > Here we go again - the first send didn't seem to get through. This is > the second attempt. > > This talk of Costas loops reminded me of something I wanted to > investigate some day. I read somewhere a while back about > carrier-phase measurements, and various methods for recovering the > GPS carrier frequencies, including the Costas loop, and something > with carrier-squaring. Nothing I found showed actual examples or > detail of how this is done, only high-order mathematical descriptions. > > For my needs, I'm more of a frequency-nut - I usually don't care > about getting time info, but I'd like perfect 10 MHz for reference. > Can using only the carriers lead to simple ways to get the same (or > better) frequency stability as a conventional GPSDO, but without the > time and location info, or is it pointless to worry about it, and > just go with full GPS decoding of everything? Or, is carrier-phase > just an enhancement only if you already have the full GPS info? > > I know that the group could redesign the whole GPS system with tubes > if necessary, considering recent philosophical discussions on that, > so I think there's plenty of knowledge here about carrier-phase > related stuff too. > > Ed > > _______________________________________________ > 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.
