HP Cell Phone Accessories E6380-90019 Manual Do Utilizador
88
Chapter 4
CDMA Measurements - Screens and Control Fields
Error Vector Magnitude (EVM) Measurements
Error Vector Magnitude (EVM) Measurements
Error Vector Magnitude (EVM) Measurements
EVM
EVM
is a measurement of the accuracy of the phase and amplitude of the
QPSK (Quadrature Phase Shift Keying) or Offset QPSK (OQPSK)
modulation. Expressed as a percentage, it is the RMS magnitude value
of the error vector which connects the ideal signal phasor to a measured
signal phasor at the detection decision points.
modulation. Expressed as a percentage, it is the RMS magnitude value
of the error vector which connects the ideal signal phasor to a measured
signal phasor at the detection decision points.
Figure 4-4 Components of Error Vector Magnitude
The magnitude of this error vector represents the “error” between the
ideal signal and the measured signal.
ideal signal and the measured signal.
As part of the measurement, the signal is corrected for clock delay,
carrier frequency, carrier phase, and amplitude scaling.
carrier frequency, carrier phase, and amplitude scaling.
Screens on which this measurement is displayed.
• CDMA ANALYZER
• CDMA GENERATOR
Magnitude Error
Magnitude Error
is the difference in the RMS magnitude value (in
percent) between the ideal signal phasor and the compensated,
measured signal phasor at the detected decision points.
measured signal phasor at the detected decision points.
Phase Error
Phase Error
is the RMS value of the difference in phase (degrees)
between the ideal signal phasor and the compensated, measured signal
phasor at the detection decision points.
phasor at the detection decision points.
Ide
al
Sig
na
l
I
M
ea
sur
ed
S
ig
nal
Magnitude Error
Ph
as
e
Er
ro
r
E
rro
r V
e
ct
o
r
Q
evm1.ds4
Main Menu