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Wireless & Mobility · Advanced

Error Vector Magnitude (EVM)

A measure of how far received symbols deviate from their ideal constellation points.

Definition

EVM quantifies modulation accuracy, usually in dB or percent. Higher-order QAM requires lower (better) EVM because constellation points are closer together. Radio datasheets specify EVM limits per MCS.

Exam tip

Tighter constellations (1024/4096-QAM) need better EVM.

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