Error Vect vs. Sample (Sym overlay) (Custom OFDM)
trace shows the value of the error vector for each point in the pre-OFDM time grid (sample x OFDM symbol). The value shown is usually EVM, but you can also choose other Trace Formats.
Each location on the x-axis corresponds to a sample in the OFDM symbol's time data (the data before the FFT is performed). When Measurement Interval is greater than 1 symbol, the points for all symbols are overlaid on each sample location. For example, when there are 10 symbols in the Measurement Interval, there would be 10 points overlaid on each sample location.
This trace allows you to see the performance of individual samples within an OFDM symbol, rather than just the performance of whole OFDM symbols as in the Error Vect vs. Sym (Carrier overlay) trace.
In addition to the individual points drawn on the trace, there is an average line (white by default) that shows the RMS average for each x-axis location (over all z-axis points for that x-axis location).
This trace is computed from the input to the N-point FFT, as compared to the other Error Vect traces. See Error Vect vs. Sym (Carrier overlay) for a diagram, and notice the N-point FFT block ("N-FFT").
To see the Error Vector data for the points after the FFT is performed, use the Error Vect vs. Carrier (Sym overlay) trace.
See Also
