Common Pilot Error (802.11n/ac/ax/be)
shows the difference between the measured and ideal pilot subcarrier symbols. The CPE error summary data provides the RMS level of the trace data as a percentage of the ideal signal.
Residual phase and frequency settling that occurs following the preamble is measured via the display. At each symbol-time in the burst, the measured symbol values of the pilot subcarriers are compared with the ideal values. The differences are averaged together producing a single complex value for each symbol-time.
The trace only includes the errors that are tracked. When Track Phase is selected, the trace has phase data. When Track Amplitude is selected, the trace has amplitude data. Track Timing applies pilot subcarrier timing error correction (frequency offset correction) to the pilot and data subcarriers. This is in addition to or . or must be selected in order for the trace to show useful information.
With Track Phase selected, the display shows the average phase error of the OFDM Orthogonal Frequency Division Multiplexing: OFDM employs multiple overlapping radio frequency carriers, each operating at a carefully chosen frequency that is Orthogonal to the others, to produce a transmission scheme that supports higher bit rates due to parallel channel operation. OFDM is an alternative tranmission scheme to DSSS and FHSS. pilots as a function of time (versus data symbol number). The is shown as phase deviation when the trace format is Unwrap Phase or Wrap Phase. Select as the Trace Format to display the as frequency deviation. With Track Amplitude selected, select or as the trace format to display the as magnitude changes.
Carrier phase drift will show up in the Error Vector Time trace, and not in the trace when is cleared. Carrier phase drift will show up in the trace, but will be mostly removed from the trace when is selected.
See Also
