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JD780A Series Analyzers
Measurement example
Figure 46
Power vs. time (frame) measurement with GSM signal analyzer
Conducting constellation measurements
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 125, you
can continue your measurement. The measurement settings can be saved and recalled as a file.
Procedure
1.
Press the MEASURE SETUP hot key.
2.
Press the Time Slot soft key to assign a time slot with which performs measurements, and then
select your desired time slot number from 0 to 7.
3.
Press the Detect Mode soft key, and then select the signal standard option: Auto, GSM, or
EDGE. Auto is set by default. The instrument applies a mask automatically based on the selected
mode.
4.
Toggle the PSK Constellation soft key between On and Off to enable or disable the PSK
constellation observation.
NOTE
The PSK constellation must be turned on to analyze EDGE signals.
5.
Optional. To set the delay, complete the following steps:
a.
Press the Miscellaneous soft key.
b.
Press the Delay soft key to set the amount of delay in µs.
c.
Enter a value by using the numeric keys. You can also use the rotary knob.
d.
Press the µs soft key.
140
Using GSM/GPRS/EDGE Signal Analyzer
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