Composite Error Vector Magnitude (1xEV-DO)
Composite 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 Error Vector Magnitude for the composite signal. Chan EVM (%rms) is the Root Mean Square (RMS) of the error vectors computed and expressed as a percentage of the square root of the mean power of the ideal signal (see About Composite Error Summary Data). To the right of the EVM value is the chip with the largest (or Peak) EVM (% Pk) and its value.
A perfect ideal signal is synthesized at the chip level and identified as the reference signal. The reference signal is subtracted from the measured signal to produce a time record of error phasors. The square root of the ratio of the mean power of the error signal to the mean power of the reference signal is computed and expressed as a percentage EVM.
You can select to not include the Composite IQ Offset error in the EVM error results with the Include IQ Offset in EVM demodulation property (tab)
This parameter is similar to Chan EVM except that it is computed at the chip rate instead of the symbol rate (see Chan EVM (Error-Vector Magnitude)).
See Also
