Chapter 16 465
W-CDMA Uplink Digital Modulation for Receiver Test
Generating a Single PRACH Signal
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 16-13 Display After the Power Parameter Changes
5. Press
Return > PRACH Timing Setup.
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