![Rohde & Schwarz FSH13 Operating Manual Download Page 299](http://html.mh-extra.com/html/rohde-and-schwarz/fsh13/fsh13_operating-manual_1477832299.webp)
R&S FSH
Digital Modulation Analyzer
Measurements on CDMA2000 Signals
Operating Manual 1173.6275.12 - 30
284
9.5.5.5 Changing the PN Offset
The standard uses the PN Offset to distinguish between base stations. The PN offset
determines the offset in the circulating PN sequence in multiples of 64 chips with
reference to the event second clock trigger.
Each signal is spread with a Walsh code of a length of 64 or 128 and a pseudo-random
noise code (PN code) of a length of 215. Each BTS sector in the network is assigned a
PN offset in steps of 64 chips.
If you use an external or GPS sync trigger, you have to adjust the PN Offset according
to the base station / sector you are measuring.
► Press the MEAS key.
► Press the "Signal Settings" softkey.
► Select the PN OFFSET menu.
► Enter the PN Offset you need (between 0 and 511).
9.5.5.6 Synchronizing to a Base Station Using a GPS Receiver
If you use a GPS receiver while performing measurements on a base station, you can
synchronize the sweep via the GPS receiver.
► Press the SWEEP key.
► Press the "Trigger" softkey.
► Select "GPS Sync" menu item.
The R&S FSH now synchronizes the sweep to the signal using the GPS receiver.
For more information about the external trigger that is also available see "
" on page .