[time-nuts] 75Z vs 50Z for GPS receivers
Poul-Henning Kamp
phk at phk.freebsd.dk
Sun Jan 28 21:52:00 UTC 2007
In message <45BD1880.9080503 at xtra.co.nz>, Dr Bruce Griffiths writes:
>I can see the difference between the short 50 ohm cable terminated in 50
>ohms and the short 50 ohm cable terminated in 75 ohms.
>It would be instructive to repeat this with a short length of 75 ohm
>cable terminated in50 and 75 ohms.
The technique for visualizing these kinds of things is called Time Domain
Reflectometry and you can do it with a good pulse generator and an
oscilloscope.
A HP5359A is perfect for the job, but less will do it.
Read here how-to:
http://www.hparchive.com/Application_Notes/HP-AppNote-62.pdf
Poul-Henning
--
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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