[time-nuts] No 1 PPS output on a Tbolt

Ed Palmer ed_palmer at sasktel.net
Mon Feb 8 03:47:00 UTC 2010


Sal:

I agree with Bob's suggestion below.  Set your trigger mode to normal 
rather than auto and use DC coupling, not AC.  Set a slow sweep speed so 
it's easy to see (maybe 10ms per division).  You should see a sweep 
every second.  By varying the trigger level control you can get an idea 
of the pulse's voltage even if you can't see it.

Ed

Bob Camp wrote:
> HI
>
> A lot depends on just how tired the tube in your scope is. Some of these scopes have spent a lot of hours turned on and wearing out the filament ....
>
> The easy thing to do is to vary the trigger point and watch the "trigger" light. It should tell you if the pulse is there or not. If it's not, then either it's turned off or there's something keeping the electrons from getting to you (like a blown chip). 
>
> Bob
>
>
> On Feb 7, 2010, at 8:56 PM, Bruce Griffiths wrote:
>
>   
>> John Ackermann N8UR wrote:
>>     
>>> Sal, what sweep time are you using on the scope?  I believe the TBolt PPS is only microseconds wide, so you may need to speed up the sweep time to around 100us/div or faster to see it accurately.  And you may need to mess with delaying the sweep to get the pulse on the screen.
>>>
>>> John
>>> ----
>>>
>>>       
>> You would need to delay the sweep by 0.999999s to get the leading edge on screen if the internal scope vertical delay line is insufficient.
>>
>> With a sweep speed of 2us/div the entire pulse is clearly visible (even without a viewing hood and light from a window (overcast sky) falling directly on the screen) without any delayed sweep.
>> NB trigger on the leading edge which has a positive slope.
>>
>> Bruce
>>
>>     




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