Chapter 16 499
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 16-2 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 16-34 on page 497 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 16-34 on page 497 and listed in Table 16-2 on page 498.
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 16-2 Multiple ESG I/O Signals and Connections
Signal Signal Type Rear Panel
Connector
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