[time-nuts] Alternate frequency sources - second opinions

Mark Spencer mspencer12345 at yahoo.ca
Mon Nov 23 17:51:27 UTC 2009


With regards to using WWV as a frequency source you need to watch out for the doppler shift of sky wave signals which can be a few hz or so.

This doccument has some more info re this.

http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA284610&Location=U2&doc=GetTRDoc.pdf




----- Original Message ----
From: Bill Hawkins <bill at iaxs.net>
To: Discussion of precise time and frequency measurement <time-nuts at febo.com>
Sent: Sun, November 22, 2009 5:32:56 PM
Subject: Re: [time-nuts] Alternate frequency sources - second opinions

IIRC, NTP turns a computer clock into a DO with millisecond accuracy.

Accuracy is stratified, with a number of Stratum 1 sources available.

Don't know if anyone has designed a collection of differentiated silicon
and stored programs that hooks to the internet and delivers a disciplined
10 MHz at 50 ohms.

Probably not, since even crystal oscillators do better than NTP. Beat
one against WWV and you were good to 10-7 or so.

Mills was working on microsecond accuracy five years ago. Where does
NTP stand now?

Bill Hawkins


_______________________________________________
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.



      __________________________________________________________________
Yahoo! Canada Toolbar: Search from anywhere on the web, and bookmark your favourite sites. Download it now
http://ca.toolbar.yahoo.com.



More information about the time-nuts mailing list