Technical data

62 Chapter 3
1xEV-DO Analyzer and Over Air Test
Making 1xEV-DO Tx Measurements
1xEV-DO Analyzer and Over Air
Test
typically only performed during Preventative Maintenance.
The first step is to choose the type of time reference available. The measurement
configuration depends upon the type of time reference you choose to use. Optimally,
a GPS time reference is desired. GPS provides an independent time reference that
can help determine if the access network under test is synchronized with the rest of
the network. Access networks not synchronized with the rest of the network are
referred to as “island cells”.
NOTE If a GPS time reference is available, you will be able to see all the metrics, and you
will be able to verify that the access network has correctly locked onto the GPS
signal.
If you connect to the access network’s
Even Second Clock, you will still get all the
metrics, but you will not have an independent check that the access network has
locked onto the GPS signal.
You need a timing reference (either GPS or ESC) to see PN Offset and Time Offset
results. When using another non-time based reference (for example,
Internal
Reference), results for PN Offset or for Time Offset will be unavailable.
You must also know the channel or frequency of the 1xEVDO signal to be analyzed.
Each access network sector is assigned a unique PN [pseudo-noise] Offset. If you
are using a GPS signal or the Even Second Clock, the PN Offset will be detected for
you. If you are making measurements without the aid of either a GPS signal or the
Even Second Clock, you will need to know the PN Offset of the Access Network
that is producing the signal to be analyzed. For more information on PN Offsets
refer to “Adding a Marker” on page 90.