
400 Chapter 15
W-CDMA Uplink Digital Modulation for Receiver Test
Overload Testing with Multiple PRACHs—Multiple ESGs
All of the I/O signal connectors can be identified using the softkeys accessed by the PRACH
Rear Panel Setup
softkey. While the input signals are fixed to specific connectors, the output
signals can be configured for various rear panel connectors. In this procedure, the connectors
listed in Table 15-2 are used.
If your BTS does not have the available power for splitting the frame synchronization signal
between both ESGs, ESG 1 can produce a synchronization signal for ESG 2. In this way, ESG
2 is synchronized with the BTS through ESG 1. This is done by using the sync pulse signal
from ESG 1. If your BTS does have the power capability for splitting the frame
synchronization signal between two ESGs, then the ESG sync pulse signal is not required.
If more than 16 UEs are required, you can connect additional E4438Cs using the ESG’s
PRACH start and sync signal features to coordinate the synchronization and start triggers.
For example, if a third ESG was needed, you would follow the connections shown in Figure
15-34 on page 398 and the configuration instructions in the following sections for ESG 2, and
apply them to ESG 3.
The versatility of the ESG lets you configure the PRACH start trigger using a LF (low
frequency) output signal. The LF output can be configured for a pulse or square-wave, or you
can use an external source. The following multiple ESG procedure uses the ESG’s LF output
as the trigger source.
Connecting the ESG to the Base Transceiver Station
Connect the equipment as shown in Figure 15-34 on page 398 and listed in Table 15-2 on
Output ESG Sync Pulse (only for ESG 1)
This is a replacement for the BTS Frame Sync
signal for ESG 2, if the BTS signal does not
have the power capability to split between two
ESGs.
EVENT 1
PRACH Start Trigger Echo Back (only for
ESG 1)
This signal is used to synchronize the
beginning of the PRACH transmission between
the two ESGs. It triggers ESG 2 to start its
PRACH transmission.
EVENT 2
Table 15-2 Multiple ESG I/O Signals and Connections
Signal Signal Type Rear Panel
Connector
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