[time-nuts] WWVB BPSK Receiver Project? (fwd)

[Bob Camp]

Hi

My main concern on short averages is the relatively long path from WWVB to
most of the target audience. The day / night phase shift is fairly
significant over a long path. That's something I would want to process out.
Since it (hopefully) is predictable, it's just another thing to feed into
the signal estimation side of the process. 

Bob

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Poul-Henning Kamp
Sent: Friday, March 16, 2012 12:27 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] WWVB BPSK Receiver Project? (fwd)

In message <34C510BB3C6449B89AC4F7FBC20F46DA at vectron.com>, "Bob Camp"
writes:

>One assumption is that you will indeed be capturing / averaging for several
>days. I'd include some sort of model for sunrise / sunset shifts (might be
>just "ignore for the next hour"). 

Some of my best results had 8 buffers each used for 3 hours and
all timenuttery based on 24 hour differences from these buffers.

>Another assumption is that your local reference is close enough and stable
>enough to make a multi day average meaningful. 

Well, the above technique got me a new offset estimate every three hours
and that did a pretty good job on both OCXO and Rb disciplining.

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.

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