Cisco Cisco DOCSIS EuroDOCSIS Transponder for GainStar Nodes and Amplifiers Installation Guide
Chapter 3 Operation
Entire QAM
constellation
I-Q
Imbalance in
the
Modulator
Overall appearance of QAM
constellation is rectangular
rather than the desired square
shape (square inequality).
Entire QAM
constellation
Quadrature
Distortion
Overall appearance of QAM
constellation has a twisted or
skewed parallelogram shape.
Sample QAM Constellation—Normal Centered Dots (Good Sound Quality)
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