[time-nuts] 1PPS questions

[Bob kb8tq]

Hi

Probably the easiest approach is an L pad at the input to the measurement device. 
Something like a 470 ohm in series and a 120 ohm to ground. A 50 ohm pad 
may not make the line driver in the source device very happy ….

Something more exotic would be to do a distribution amp. Use a NC7SZ125 at the 
input so it’s 5V tolerant. Run however many of them you need to drive the desired
number of outputs.  Power it all off of 2V and you have 2V p-p output(s).

Keep in mind that 2V p-p “logic” signals may or may not trigger CMOS level stuff 
powered off of 3.3V. CMOS running on 5V gets into the “not going to happen” 
area. 

Bob



> On Jul 1, 2020, at 9:37 PM, VE7HR <ve7hr at ve7hr.ca> wrote:
> 
> Are there any suggested method to reduce your 1 PPS signal to a safe level for your test equipment?
> It seems like my HP Z8316A is outputting slightly more than 5V into 50 Ohms. 
> 
> Up till now I have been using a 10 MHz output from the Z3816A. But I understand 1PPS is a better signal to put to Channel A. 
> 
> My HP 5372A seems to default to 2V Max level if you hit instrument default.  I am starting to like it so I don’t want to trash an input module.  
> 
> I think I might try a TICC in the near future but for now I will have to slum with the vintage HP iron. 
> 
> Thanks
> Dave
> VE7HR 
> 
> Sent from my iPhone
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