Satlink ST-5810 - Constellation Analysis; Understanding Constellation Diagrams

ST-5810 Operation Manual
Copyright © 2019-2022 SatLink Elextronics 23
4.5 CONSTELLATION
Quadrature Amplitude Modulation, QAM is a form of modulation that is a combination of phase modulation and amplitude
modulation. The QAM scheme represents bits as points in a quadrant grid know as a constellation diagram. Constellation
diagrams are used to graphically represent the quality and distortion of a digital signal. In practice, there is always a
combination of modulation errors that may be difficult to separate and identify, as such, it is recommended to evaluate the
measured constellation diagrams using mathematical and statistically methods.
Tap to select
zoom
in quadrant
Constellation diagram
Drop down to list channels of
current Network profile for
Change frequency manually for
constellation diagram
measurement
Modulation type
Power level
Zoom
In /
Out
Scroll up/down by arrow keys ▲▼to
select channel for power level
measurement; frequency is reflected by
selected channel (number)
Dropdown of Network profile for
selection