JD780A Series Analyzers
Measurement example
Figure 128 Power vs. time (frame) measurement with LTE – TDD signal analyzer
Conducting modulation measurements
Constellation
The Constellation is used to observe some aspects of modulation accuracy and can reveal certain
fault mechanisms such as I/Q amplitude imbalance or quadrature imbalance. It displays constellation
diagram by modulation types.
Setting measure setup
After configuring test parameters as described in the "Configuring test parameters" on page 265, you
can continue your measurement. The measurement settings can be saved and recalled as a file. You
can also use JDViewer, PC application software to configure a measure setup, save as a file, and load
the file on to the instrument.
Procedure
1.
Press the MEASURE SETUP hot key.
2.
To set the nominal channel bandwidth to be measured, complete the following steps:
a.
Press the Bandwidth soft key.
b.
Select the bandwidth option: 1.4 MHz, 3 MHz, 5 MHz, 10 MHz, 15 MHz, or 20 MHz.
3.
To select the subframe number to be measured, complete the following steps:
a.
Press the Subframe No soft key.
b.
Enter a value by using the numeric keys. You can also use the rotary knob.
NOTE
For MBMS testing, this subframe number must be neither 0 nor 5 as these subframes 0
and 5 are not available for MBMS and it must be set to the MBMS transmitted channel's
subframe number.
c.
Press the Enter soft key.
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Using LTE – TDD Signal Analyzer