[time-nuts] pulse height

[shalimr9 at gmail.com]

Said,

I agree. I intended to complete the page by doing more tests, but the interesting point of the demonstration is that it is sufficient to match the cable at the far end, and in doing so, you preserve the full amplitude of the pulse. If you put 45 ohms in series and terminate in 50 ohms at the other end, you end up with half the signal. However you do not need to do that.

That was the reason why I wrote the page in the first place. I will try to clarify that when I get a chance.

Didier

Sent from my Droid Razr 4G LTE wireless tracker.



-----Original Message-----
From: SAIDJACK at aol.com
To: time-nuts at febo.com
Sent: Mon, 26 Nov 2012 2:36 PM
Subject: Re: [time-nuts] pulse height

Didier,
 
Oh, ok that makes sense, but that is a non-standard output, so not sure  
that you want to use such an output as a sample case for generic applications. 
 Alternatively maybe rename the page to "Trimble CMOS-output Coax Cable 
Impedance  Matching" to make that clear.
 
It would be better to put a 45 Ohms series resistor in that system to give  
you a 50 Ohms standard output, and redo the tests.
 
BTW: we have had to put up with that (in my opinion) stupid output  
impedance, on our Mini-JLT boards we are also driving the 1PPS with very low  
impedance to be compatible to the discontinued Mini-T.
 
I wish Trimble had heard of incident-wave switching when they designed all  
of their units, and used a proper 50 Ohms output impedance.
 
bye,
Said
 
 
In a message dated 11/26/2012 11:12:32 Pacific Standard Time,  
shalimr9 at gmail.com writes:

Said, in  the text I indicated the source was not a 50 ohm terminated 
signal generator,  but the 1 pps output of a Thunderbolt with about 5 ohm 
impedance, hence the  ringing.

Didier 

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