Dropping Errored 1PPS Samples (CAT v33 and earlier)

When a 1PPS pulse is not detected for a particular second during a capture, Paragon-neo/Paragon-X flag the sample as No 1PPS. Such a sample will have the same TE of the previous sample. Historically CAT treated that sample as a valid 0ns sample in the 1PPS metrics.

As of v34.00, CAT been updated to handle this situation better. For any metrics which use the 1PPS TE as a data source, CAT now drops samples marked with the “No 1PPS” error and they are not used for calculations.

This example shows a capture where several samples contain errors:

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In the table there is a mix of No 1PPS errors and CRC errors. CRC errors in the ToD portion of the 1PPS ToD capture do not affect the 1PPS TE value so they are not treated as “Errored Samples” in the chart or the statistics of the Time Error metric. The samples at the locations of the red error bars are dropped in metrics that derive from the Time Error data.

This capture has 3 messages marked as No 1PPS.

The 1PPS Filtered TE metric is based on the same data as the previous TE screenshot. The statistics show that the count of Errored Samples In Range is three. Only one error bar is shown because the metric cuts off the initial part of the capture to allow for filter settling.

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The sample at the location of the red error bar has been dropped in the Time Error data that this metric uses as source data. This means that CAT does not provide a filtered time error sample for that data point.

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MTIE has no time-series data so CAT does not show any error bars on the MTIE graph. The Errored samples in range statistic is still 3 which is an indication that further investigate of the cause of the errors is required to determine if they are acceptable for the test case.