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

[Brooke Clarke]

Hi Didiere:

There's also an app note at Linear Technology for making pulses so fast 
they are used to calibrate sampling scopes.

Some years ago I made a very simple circuit that pulses a LED with many 
amps (very short time) based on a transistor going into avalanche.

Have Fun,

Brooke Clarke

w/Java http://www.PRC68.com
w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml
http://www.precisionclock.com



Didier Juges wrote:

>Bruce,
>
>I finally found the time to google for avalanche pulse generator and 
>found an App note from Zetex on the subject.
>I was not familiar with this technology, but it seems interesting.
>Amazing that you can get 50A pulses with sub-ns rise time out of a 
>device in an SOT-23 (or TO-92) package!
>
>I have uploaded the app note to 
>http://www.ko4bb.com/Test_Equipment/AvalanchePulser
>
>Now, I just need a scope fast enough to take advantage of such a short 
>rise time. Back to eBay again :-)
>
>Didier
>
>Dr Bruce Griffiths wrote:
>  
>
>>Didier
>>
>>You can always build your own 100A avalanche transistor pulser using 
>>several Zetex FMMT413s.
>>
>>Bruce
>>
>>Brooke Clarke wrote:
>>  
>>    
>>
>>>Hi Didier:
>>>
>>>Yes they are on eBay.  The tunnel diode models have a narrower pulse 
>>>than the later models that use something more rugged.  Probably for all 
>>>practical purposes one of the newer ones would work well and last 
>>>better.  I think the military bought boat loads of these and I've heard 
>>>from a number of people that use them and like them a lot.
>>>
>>>Have Fun,
>>>
>>>Brooke Clarke
>>>
>>>w/Java http://www.PRC68.com
>>>w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml
>>>http://www.precisionclock.com
>>>
>>>
>>>
>>>Didier Juges wrote:
>>>
>>>  
>>>    
>>>      
>>>
>>>>Going over the spec for the 1502, it seems like a nice instrument. I am 
>>>>worried about the fragility of the tunnel diode though. When my neighbor 
>>>>AD4TK fires up his amplifier, I have measured up to 1W of his signal 
>>>>going down my feedline (on the 80m slopper antenna)...
>>>>
>>>>Are these things on eBay?
>>>>
>>>>Didier KO4BB
>>>>
>>>>Brooke Clarke wrote:
>>>> 
>>>>
>>>>    
>>>>      
>>>>        
>>>>
>>>>>Hi Didier:
>>>>>
>>>>>The Tek 1502 is great for doing this, especially if you have the 
>>>>>optional strip chart recorder.  It's what it was made to do.
>>>>>http://www.pacificsites.com/~brooke/Tek1502.shtml
>>>>>
>>>>>Have Fun,
>>>>>
>>>>>Brooke Clarke
>>>>> 
>>>>>   
>>>>>
>>>>>      
>>>>>        
>>>>>          
>>>>>
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>>>>
>>>>    
>>>>      
>>>>        
>>>>
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