[time-nuts] 75Z vs 50Z for GPS receivers

Dr Bruce Griffiths bruce.griffiths at xtra.co.nz
Sun Jan 28 22:06:40 UTC 2007


Poul-Henning Kamp wrote:
> 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

The Tektronix booklet:
/ Time-Domain Reflectometry Measurements by James A Strickland
/from their measurement concept series is also instructive, at 102 pages 
it has far more detail and examples.

Unfortunately a quick search failed to find  a scanned version of this 
on the web.
I have a copy so if there were sufficient demand I could scan it.

Bruce




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