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Coherent Modulation Transmitter | IQTX
Quantifi Photonics Ltd.
Version
1.04
71
14
Measurement definitions
IQ RF imbalance
The IQ RF imbalance is the ratio of the in-phase
component versus the quadrature component of
the constellation points.
The ratio is represented as a percentage, so 10%
IQ RF imbalance would mean that the in-phase
component is 10% larger than the quadrature
component.
Figure 16 - IQ RF Imbalance for QPSK
Equation 3 - IQ RF Imbalance Calculation
Error vector
The error vector can be separated into its two primary components: Error Vector Magnitude (EVM) and
Phase Error (PE). The error vector magnitude is the magnitude of the error vector, which is the
difference between the signal vector and the ideal reference vector. It is more convenient to represent
the EVM as a percentage to make it independent of the average signal power, as shown in Equation 5.
The phase error is the phase difference between the signal vector and the ideal reference vector, as
shown Equation 6.
Equation 4 - Error Vector Magnitude Calculation
Equation 5 - Phase Error Calculation
Error Vector, Single Sample Point
Содержание IQTX 1100 Series
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