[time-nuts] Why are 1PPS signals so skinny?

bg at lysator.liu.se bg at lysator.liu.se
Mon May 14 16:33:28 UTC 2012


Mark & Azelio,

Or even 10V into 50ohm, 20us... See figure 3-4 in ICD-GPS-060.

    http://www.navcen.uscg.gov/pdf/gps/ICD-GPS-060B.pdf

More modern 3-5.5V into 50ohm, 20us.
         http://contracting.tacom.army.mil/majorsys/jab/DAGR%20Interface%20Specification.pdf

Above are two standards demanding short skinny 1PPS pulses. Are there any
other standards with distinct shape requirements on 1PPS pulses?

--

   Björn

> Feed a 5V 1Hz square wave into a 50OHM load and look at the power drain.
> Do
> the same with a 100uS pulse and smile at the difference.
>
> On Mon, May 14, 2012 at 5:23 PM, Mark Sims <holrum at hotmail.com> wrote:
>
>>
>> My first inclination,  if I were building a timing receiver,  would be
>> to
>> make the PPS output a nice,  symmetrical square wave.   But pretty much
>> all
>> GPS timing receivers output an anorexic,  dinky little heroin addicted
>> supermodel sized pulse (from 1 to 150uS wide is typical).




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