[time-nuts] Why are 1PPS signals so skinny?
mblazer at satx.rr.com
Mon May 14 22:55:01 UTC 2012
https://assist.daps.dla.mil/quicksearch/ is the search site for
military standards. MIL-188-155 is not found. Could it be another dash
On 5/14/2012 2:20 PM, Magnus Danielson wrote:
> Mark, Azelio and Björn,
> On 05/14/2012 06:33 PM, bg at lysator.liu.se wrote:
>> Mark& Azelio,
>> Or even 10V into 50ohm, 20us... See figure 3-4 in ICD-GPS-060.
>> More modern 3-5.5V into 50ohm, 20us.
>> Above are two standards demanding short skinny 1PPS pulses. Are there
>> other standards with distinct shape requirements on 1PPS pulses?
> You need to look at MIL STD 188/155 which if I recall things was
> initially formed in the 60thies.
> An AccuBeat presentation actually says that the PPS was originally
> defined in it.
> The MIL STD 188/155 is actually a 10 V peak level, so it was much
> hotter than we are used to know. It specified 5 MHz as base frequency,
> or power of 2 multiples (10, 20, 40 MHz... ).
> It was later reformulated in the PTTI spec, which ICD GPS 060 is a
> derivate. The 50 ns rise and 1 us fall slopes comes from that spec.
> I was not able to find MIL STD 188-155 on the net right now, but I
> have been able to download it before, so if someone is a more lucky it
> should surface. I should have my download somewhere.
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