an orthogonal frequency division multiplexed (OFDM) output signal produced by a device in response to an OFDM input signal is accessed. The OFDM input signal includes OFDM input symbols in the time domain and the OFDM output signal includes OFDM output symbols in the time domain. The OFDM output symbols are time-aligned to the OFDM input symbols and a phase of the OFDM output signal is de-rotated with respect to the OFDM input signal. A complex equalization filter is applied to the OFDM output symbols in the time domain to obtain an estimate of the OFDM input symbols A distortion signal of the OFDM output signal is determined by subtracting the estimate of the OFDM input symbols. An error vector magnitude (EVM) is determined by dividing a root mean square of the distortion, by a root mean square of the OFDM input signal.