About Cdma Receivers - Viavi T-BERD MTS 5800 Getting Started Manual

Chapter 4 Basic Testing
Preparing to test

About CDMA receivers

CDMA base stations are synchronized to GPS time provided by a GPS Satellite; the
time is then broadcast to the CDMA receivers connected to your instruments. Alterna-
tively, if your instruments use GPS receivers, the receivers obtain highly accurate timing
information directly from a GPS Satellite (there is no intermediary base station).
Your instruments use the messages and signals provided by the CDMA or GPS
receivers to synchronize their internal clocks with GPS time. The receivers provide 1)
periodic messages with GPS time via the DB9, RJ-45, or USB connector on the instru-
ments, and 2) an accurate 1PPS signal into the BNC, SMA, or SMB connector.
Outgoing packets are then marked with GPS timestamps. If your instruments are
configured and optioned to do so, both test ports can be used, allowing you to measure
one way delay for two different circuits simultaneously. Connecting a CDMA Receiver
to an instrument
When you use CDMA receivers to synchronize your test instruments, the receivers
communicate with each other to establish synchronization.
Figure 54 illustrates each of the required connections for a CDMA receiver connected
to a T-BERD ⁄ MTS 5800 or a MTS6000 or MTS8000v2 base unit with a CSAM or
MSAM module.
Figure 54 CDMA connection for one way delay measurements
T-BERD/MTS/SC Getting Started Guide
March 2018 22046537, Rev. 016 Page 91