Agilent Technologies E4428C, Руководство пользователя

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332 Chapter 10
CDMA Digital Modulation
cdma2000 Reverse Link Modulation for Receiver Test
• “Setting the Carrier to Noise Ratio” on page 332
• “Setting EbNo” on page 332
Setting the Carrier to Noise Ratio
1. Press
Mode Setup
to return to the top-level real-time cdma2000 menu.
2. Press
Noise Setup
>
C/N
>
10
>
dB
.
3. Press
Noise Off On
to On.
You have now set the overall carrier to noise ratio to 10 dB and turned on noise. This is done to apply a
discernible level of noise across the entire channel space.
Setting EbNo
EbNo can be set in the Noise Setup menu or the Channel Setup table editor (see “Modifying Channel
Parameters” on page 329 ). This task teaches you how to make quick EbNo adjustments using the
EbNo
softkey in the Noise Setup menu.
1. Press
Channel Number
and move the cursor to highlight the reverse fundamental channel (R-FCH).
2. Press
EbNo
>
20
>
dB
.
You have now set the EbNo value for the R-FCH channel to 20 dB. Note that modifying the EbNo value for
a channel will change the overall carrier to noise ratio and the EbNo value for all other active channels. For
reliable results when making hand calculations to determine or verify EbNo values, it is recommended that
you first scale the code domain power to 0 dB to display the normalized relative channel power levels (see
“Scaling to 0 dB” on page 330 ).
Generating the Baseband Signal
This procedure builds upon the previous procedure.
Press CDMA2000 Off On to On.
This generates the real-time reverse link cdma2000 signal. The signal generator may require several seconds
to build the signal. During this time,
Baseband Reconfiguring
appears on the display. After the
reconfiguration is complete, the display reads
CDMA2000 On
and the
CDMA2K
and
I/Q
annunciators appear.
The signal is now modulating the RF carrier.
The signal’s configuration data resides in volatile memory and is not recoverable after an instrument preset,
power cycle, or reconfigured signal generation.