Monitoring signal characteristics
R&S
®
SMM100A
426
User Manual 1179.1341.02 ─ 05
Signal acquisition points:
See
.
Power spectrum
The power spectrum displays the signal spectrum which is calculated from the I/Q sig-
nal with fast Fourier transform (FFT). The power density over frequency is displayed.
Figure 8-6: Power spectrum diagram of a 5 MHz LTE signal with enabled reference curve (blue)
"FFT points" = indicates the number of I/Q value pairs that are used for calculating a (part-)FFT
"AVG"
= indicates the number of subspectra used for averaging
X-axis
= frequency plotted symmetrically (- Sampling Rate/2 to +Sampling Rate/2)
Y-axis
= power density
Signal acquisition points:
See
.
8.1.2.2
Signal acquisition points
Signal characteristics can be displayed using different methods and different acquisi-
tion points, also at the same time.
shows which signal acquisition point is
suitable for which kind of graphics mode. Also, it provides associated graphics sources
and the designation of the access points in the block diagram.
Table 8-2: Signal acquisition points, modes and sources
Signal acquisition points Graphics modes
Graphics source
Designation
Baseband signals
Constellation diagram, eye diagram
"Baseband"
"BB Input"
Input streams
I/Q diagram, vector diagram, CCDF
diagram, power spectrum diagram
"Stream"
Analog outputs
I/Q diagram, vector diagram, CCDF
diagram, power spectrum diagram
"IQ Out"
"RF"
Digital output streams
I/Q diagram, vector diagram, CCDF
diagram, power spectrum diagram
"IQ Digital"
Displaying baseband signal characteristics in real-time