Knowing the propagation delays of 1pps signals passing through the Option 133 1pps/ToD/Frequency Converter is critical when setting the Paragon-Neo 1pps reference and measurement compensation values.
To minimise the effect of variation between individual converters, users can measure the propagation delays of a specific Option 133 converter using the test sequence described here. The yellow dots in picture below shows the location of 1pps propagation delays in the Rev C and Rev D Option 133 Converter.
KG note – intention is to focus on 1pps propagation delay measurement and not mention ToD delays. OK ?Propagation delays on the ToD message paths through the converter are small enough not to affect ToD measurements.
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The functionality of the 1pps paths between ports is given in the table below.
Input Port | Output Port | Notes | ||
Port 1 Balanced 1pps In | RJ45 pins 3+6 | Port 2 Unbalanced 1pps Out | RJ45 pins 1+2 | |
Port 1 Balanced 1pps In | RJ45 pins 3+6 | Port 7 Unbalanced 1pps Out | BNC | Rev D only |
Port 3 Unbalanced 1pps In | RJ45 pins 1+2 | Port 4 Balanced 1pps Out | RJ45 pins 3+6 |
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Port 3 Unlalanced Unbalanced 1pps In | RJ45 pins 1+2 | Port 7 Unbalanced 1pps Out | BNC | Rev C only |
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The example screenshots below show the Paragon-neo 1pps Time Error Measurement application with appropriate delay compensation, and the Time Error results in CAT. The cables used in this example were 0.64m length at 5.1ns/m gives a Delay Compensation of 3.26ns. The red arrows highlight the relevant status indicators. CAT show the delay through this example Option 133 Converter port3 to port 4 is 18.5ns6ns
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