Problem
In order for your 1pps signal to be recognised by the Paragon instrument, you need to make sure that your input signal (both reference and measurement inputs) is at the correct level.
Solution
Front panel 1PPS (aux) input
The maximum allowed voltage depends on the duty cycle. The termination resistor on the P-X is a bit feeble – only 0.1W power rating. So applying V^2/R, the maximum value of V(HI) that is possible (assuming V(LO) = 0) and average power of 0.08W (80% rating) would be as follows for different duty cycles.
| Duty cycle | max V(HI) |
|---|---|
0.1 | |
0.2 | |
0.1 6.3
0.2 4.5
0.3 3.65
0.4 3.2
0.5 2.8
0.6 2.6
0.7 2.4
0.8 2.24
0.9 2.36
1.0 2.5 (constant 2.5V input)
So probably the safest answer is 2.5V (with termination enabled). To cover scenario with 50/50 duty cycle, 2.8V is max (3.2V if assuming power dissipated in resistor is 0.1W ).
1PPS reference input
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