User`s guide

402 Chapter 15
W-CDMA Uplink Digital Modulation for Receiver Test
Overload Testing with Multiple PRACHs—Multiple ESGs
and the ESG selection was 40 msec, an out of synchronization condition will occur. The
results of the example are shown in Figure 15-35. An ESG frame clock interval of 10 or
20 ms will resolve the out of sync condition. This applies to ESG 1 and ESG 2 if they are
both directly connected to the BTS frame timing interval signal. However, if ESG 2 is
synchronized using the ESG Sync Pulse signal from ESG 1, then its frame interval
selection, if incorrect, may cause only a temporary out of synchronization condition that is
self-corrected. This is because ESG 2 is synchronized with ESG 1 and not directly with the
BTS. See “PRACH Synchronization” on page 449 and “Frame Sync Trigger Status
Indicator” on page 451 for more information.
Figure 15-35 Out of Synchronization Annunciator
6. Press
Return > Return > PhyCH Setup > PRACH Trigger Source Immedi Trigger to Trigger.
Using the task, “Controlling the PRACH Transmission” on page 383, you can set the
number of 80 ms period repetitions for a finite number of PRACH transmissions, or using
the infinity selection, you can enable a continuous PRACH transmission once the PRACH
start trigger is received by the ESG.
NOTE In order to have a finite number of transmitted 80 ms periods, you will need to
ensure that the PRACH trigger source is disabled once the PRACH
transmission starts. If the trigger source is not disabled, the PRACH signal will
retrigger after the entered number of 80 ms periods are transmitted.
Figure 15-36 shows the frame trigger menus after all selections have been completed. Your
selection for the Frame Clock Interval may be different than what is shown. If you have kept
your PRACH trigger source active, you will see the RACH Trg annunciator gray-out
intermittently as the transmission from the trigger expires and a new trigger is acquired.
Out of Sync
Annunciator