[time-nuts] Trimble Thunderbolt 1PPS TTL level?

Björn Gabrielsson bg at lysator.liu.se
Sat Aug 30 14:32:50 UTC 2008


On Sat, 2008-08-30 at 16:12 +0200, Arnold Tibus wrote:
> On Fri, 29 Aug 2008 22:21:43 -0400, Pieter Ibelings wrote:
> 
> >Hi All,
> 
> >I got a Trimble Thunderbold from Ebay and I am having trouble triggering the 
> >HP 53131A. The 1PPS output shows a 10us  pulse of 1 Volt into a high 
> >impedance probe. This seems low to me. Should it be 5 volts? Maybe the 
> >output 74AC04 is toast?
> 
> >Pieter, N4IP
> 
> Hi Pieter,
> there is nothing to be worried about, I have the same problem with my
> 53132A, it does not trigger on it with 50 ohms or high impedance load. 
> So I tried it with the 5334A - no problem at all ! It does trigger as expected, 
> without any signal loss. 
> Seem to be a problem of the 53131A/ 53132A series counter.
> 
> regards,
> Arnold

Hi all,

My PM6681 (aka CNT81) on automatic trigger level, fails to identify a
reasonable trigger voltage.

When set manually, there is no trigger problems at all.

--

   Björn





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