A.3.3
Modem Demodulator Constellations
View the modem demodulator constellations by using the IQ Mon application on the user computer.
The IQ Mon uses the modem ethernet management connection to retrieve the constellation
information. Typical constellation patterns are shown in Figure A-5 through Figure A-10. Error
Vector Magnitude (EVM) is a measure of how far the points are from the ideal quadrature locations.
The smaller the dot, the bigger the number.
Extremely high composite power will add to the noise received by the modem. Frequency
separation and balanced carriers are essential to satellite system operation.
Appendix A
SLM-5650C / SLM-5650C-ODU Satellite Modem
Figure A-5. BPSK Constellation
Figure A-6. QPSK Constellation
A–8
Revision 1
MN-SLM-5650C