JDS Uniphase CellAdvisor JD780A Series, User Manual

Page: 348 / 592

JD780A Series Analyzers
348
Using CDMA Signal Analyzer
Conducting modulation measurements
In order to make accurate measurements of time offset and PN, you must connect an external trigger
before making a modulation measurement.
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 334, 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 Pseudo-Noise (PN) offset, complete the following steps:
a. Toggle the PN Offset soft key between Auto and Manual .
b. Enter a value by using the numeric keys to set manually.
c. Press the Enter soft key.
3.
To set the incremental step for the PN offset, complete the following steps:
a. Press the PN Increment soft key.
b. Enter a value by using the numeric keys.
c. Press the Enter soft key.
4.
Optional . Go to SAVE/LOAD > Save , and then select the save option from the choices available
for your measurement mode. See
“Using save” on page 31 for more information.