evm phase noise
additional info. on EVM
Error Vector Magnitude (EVM) is a figure of merit for modulation accuracy. Any device that exhibits AM-AM and AM-PM distortion such as power amplifier will degrade the EVM.
The DSP stages such as pulse-shaping filters and D/A conversion can have a significant effect on overall EVM
i.e the impact of phase imbalance, amplitude imbalance, and dc-offset you can see on the EVM measurement...The best EVM (approximately 1.0%) is achieved when all imbalances are set to zero...
Also
The EVM measurement is described mathematically as:
|(Vrx - Vref)|^2
EVM (%) = 100 * -----------------
|Vref|^2
where Vrx is the complex received signal (from the demodulator) and Vref is a perfect (ie undistorted) complex reference signal.