
446 Chapter 15
W-CDMA Uplink Digital Modulation for Receiver Test
W-CDMA Uplink Concepts
Figure 15-65 illustrates the frame number alignment for the DPCH channel. The frame
number is aligned by the frame sync trigger signal from the BTS. When using the frame clock,
set the frame clock period to be equal or greater than the longest transport channel TTI period
(select 10, 20, 40, or 80 ms). In Figure 15-65, Reference Measurement Channel 12.2k requires
a frame clock of 20 ms or longer to achieve the correct frame number alignment. Using a
frame clock of 10 ms would cause an unpredictable frame timing alignment with the transport
channel TTI period. Best results are achieved when the frame clock is set to 80 or 2560 ms, or
a system frame number reset signal is used. (The signal generator’s TTI period can be
measured on the TTI frame pulse from the rear panel.)
Figure 15-65 DPCH Synchronization - Frame Number Alignment
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