Common Pilot Error (MB-OFDM)

Menu Path: Trace > Data > Composite > Common Pilot Error

The composite Common Pilot Error trace shows the difference between the measured and ideal pilot subcarrier symbols for all occupied bands. The CPE error summary data provides the RMS level of the Common Pilot Error trace data as a percentage of the ideal signal. This is displayed in the Band Err trace data as well for CPE.

The number of symbols in the trace x-axis and Start and Stop readings correspond to the settings for Result Length, Measurement Offset, and Measurement Interval. To learn more, see Lengths, Intervals, and Offsets.

In addition, the setting of Phase Tracking Average Length adjusts the trace data to show the average phase error of the pilot subcarrier symbols to be included in the calculation, based on symbol-times. Entries for Phase Tracking that exceed the entry for Measurement Interval are ignored. For example, if Measurement Interval is set for 12 symbol-times, then values of Phase Tracking over 12 symbol times have no meaning to the calculations.

Setup Example

Measurement Offset = 0 | Measurement Interval = 12 | results in a trace with Start = 0 | Stop = 11.

Measurement Offset = 6 | Measurement Interval = 2 | results in a trace with Start = 6 | Stop = 7

For small sized Measurement Intervals, particularly with TFI (hopping) TFC Transport Format Combination's 1-4, the phase and frequency error can be fully compensated for so there is no error displayed.