EVM (GSM/EDGE/EDGE Evolution)

EVM Error vector magnitude (EVM): A quality metric in digital communication systems. See the EVM metric in the Error Summary Table topic in each demodulator for more information on how EVM is calculated for that modulation format. is the Root Mean Square (RMS) of the error vectors computed and expressed as a percentage of the RMS average of the ideal symbol points in the demodulated Timeslot. EVM is the RMS average of the error vectors—at the detected symbol locations—which connect the reference I/Q-signal vectors to the measured I/Q-signal vectors. EVM is computed as follows:

EVM is calculated using only the error vectors at the symbol times (the instant in time when symbols are detected).

When the EVM is larger than expected, see Troubleshooting.

The EVM metric in the Summary Table also shows the peak EVM value and symbol location. The peak EVM value only supports Continuous Peak Hold averaging; to calculate an RMS average of peak EVM, use the Pk EVM metric.