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8PSK Modulation Accuracy Measurement Graphics

With the increasing need for higher data rates in cellular networks, EGPRS is rapidly growing as a capability in GSM networks and GSM phone models. The noise-like nature of the EGPRS modulation format (8PSK) makes it necessary for both development and production test engineers to effectively test Error Vector Magnitude (EVM) on phone designs.

The ability to look at a signal and deduce the source of a problem is important to successful design and production troubleshooting. Agilent Technologies has added EGPRS EVM graphical measurement capability to the E6601A Wireless Communications Test Set to provide the flexibility and capability to help determine the source of errors in the RF and IF sections of the transmitter. Common errors like IQ error, symbol rate errors, LO instability, interfering tone and AM-PM conversion all manifest themselves in differing, but identifiable ways in EVM.

Key Measurements

  • Peak and rms EVM
  • Peak and rms magnitude error
  • Peak and rms phase error
  • EVM vs symbol display
  • Magnitude error vs symbol display
  • Phase error vs symbol display

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Figure 5