Guide to Spectrum and Signal Analysis

Guide to Spectrum and Signal Analysis
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Guide to Spectrum and Signal Analysis

  • www.anritsu.com | 41Error Vector MagnitudeAs indicated earlier, signal analyzers are used to measure digital modulation. Vector and constellation diagrams are used to display the results. Error Vector Magnitude (EVM) is a measure used to quantify the quality or performance of a modulated signal from a transmitter or receiver. In simple terms, if we consider a constellation diagram the EVM is the magnitude of the difference between the measured vector and the ideal (reference) vector. See Figures 47 and 48.EVM is influenced by a number of IQ-parameters; Phase Error, Frequency Error, Magnitude Error, and Phase Noise. Figure 48Figure 47MagnitudeErrorErrorVectorMeasuredVectorReference(Ideal)QIPhase Error(I/Q Error Phase)ø