
366 Chapter 15
W-CDMA Uplink Digital Modulation for Receiver Test
Generating a Single PRACH Signal
PRACH power.
3. Set the power ramp for multiple preambles.
a. Move the cursor to highlight the Ramp Step field.
b. Press
7 > dB.
This setting enables a power ramping when multiple preambles are used. Each successive
preamble transmission from the second to the last will increase in power by 7 dB.
4. Select the number of transmitted preambles.
a. Move the cursor to highlight the Num of Pre field.
b. Press
4 > Enter.
The number of transmitted preambles is now four, which means that the PRACH
initial/starting power level (first preamble) will be −41 dBm. The fourth preamble will be
transmitted at the PRACH power level set in step 2b or
−20 dBm. This means the first
three preambles will have power levels that are in increments of 7 dB less than the fourth
preamble. The initial power (first transmitted preamble power level) is calculated as
follows:
3 x 7 dB = 21 dB
−20 dBm − 21 dB = −41 dBm initial power
NOTE When setting the Max Pwr, Ramp Step, and Num of Pre fields, they need to
be done in the order shown. If you do not set them in the order shown, errors
may occur and values may automatically change to accommodate limits.
Figure 15-13 Display After the Power Parameter Changes
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