[time-nuts] Speaking of Costas loops

[Bob Camp]

Hi

Ok, cook book style:

Take the carrier, amplify it up, drive an agc to keep it up.
Drive the carrier into a full wave bridge rectifier made with low barrier diodes
Take the rectified output and feed it into a bandpass filter at 2X the carrier
The output is the squared carrier

There are at least a half dozen other ways to do the squaring.

Bob

On Jul 2, 2013, at 2:21 PM, ed breya <eb at telight.com> wrote:

> 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 -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.