Rohde & Schwarz R&S CMW-KM300, Руководство пользователя, Страница: 220 / 388

NB-IoT Multi-Evaluation Measurement
R&S
®
CMW-KM300/-KS300
220 User Manual 1178.5689.02 ─ 06
Figure 3-12: I/Q constellation diagram
The constellation diagrams depend on the modulation type. For an ideal signal, the
QPSK constellation diagram consists of four points, on a circle around the origin, with
relative phase angles of 90 deg. An ideal BPSK constellation diagram consists of two
points, with equal distance to the origin. The I value of each point equals its Q value.
Constellation diagrams give a graphical representation of the signal quality and can
help to reveal typical modulation errors causing signal distortions.
The NB-IoT constellation diagram shows the following peculiarities:
●
The I/Q amplitudes correspond to the values that the R&S CMW uses for the EVM
calculation: A possible I/Q origin offset is already subtracted out.
●
Due to the properties of the NB-IoT signal, a pure I/Q imbalance causes circular
constellation points.
For the parameters on the right, see Chapter 3.3.2.13, "Common View Elements" ,
on page 225.
For query of the diagram contents, see Chapter 3.5.3.15, "I/Q Constellation Results" ,
on page 306.
3.3.2.8 View Power Monitor
The power monitor view displays the power in the captured slots.
GUI Reference
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