The maximum allowed voltage 1PPS input voltage which can be applied to the Paragon-X upper aux measurement port depends on the its 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.The table below specifies the maximum upper voltage level assuming the V(lo)=0:
| Duty cycle | max V( | HIHi) |
|---|
| 0.1 | 0.2 |
0.1 02 03 04 05 06 07 08 09 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
so, for example, a 1PPS signal with a 50:50 duty cycle should have a maximum V(HI) of 2.8V. Application of a signal voltage higher than those in the table may cause damage to your Paragon-X hardware and so must be avoided.
For optimal detection of your 1PPS pulse, the threshold should be set in the Measurement Ports tab of the Setup Interface window to a value approximately half of V(Hi).  Image Added
The measurement1 PPS signal must be received within 500ms of the reference 1PPS input. Signals outside this window will be indicated as a missing pulse in the Paragon-X GUI and CAT by a vertical red line:  Image Added
The threshold value for your 1PPS reference input signal (connected to the rear of Paragon-X) may also be adjusted, via the References tab of the Setup Interface window:  Image Added
|