JDS Uniphase CellAdvisor JD780A Series, User Manual

Page: 463 / 592

JD780A Series Analyzers
Using Mobile WiMAX Signal Analyzer
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4.
Optional . Press the More (1/2) > Trace Info soft key, and then select the trace number to view
the trace
’s parameter setting information stored at the time of the measurement or
None to hide
the information display.
5.
Optional. If you have the two traces T1 and T2, you can perform trace math. To view the power
difference between the traces, press the T1
– T2 -> T5
or T2
– T1 -> T6
soft key.
The result is overlaid on the screen along with the second Y-axis.
Conducting RF measurements
Channel power
The Channel Power measurement is a common test used in the wireless industry to measure the total
transmitted power of a radio within a defined frequency channel. It acquires a number of points
representing the input signal in the time domain, transforms this information into the frequency domain
using Fast Fourier Transform (FFT), and then calculates the channel power. The effective resolution
bandwidth of the frequency domain trace is proportional to the number of points acquired for the FFT.
The channel power measurement identifies the total RF power, power spectral density (PSD) and peak
to average ratio (PAR) of the signal in the Mobile WiMAX channel bandwidth.
Setting measure setup
After configuring test parameters as described in the
“Configuring test parameters” on page 456, you
can continue your measurement.
Procedure
1.
Press the MEASURE SETUP hot key.
2.
Press the System Config soft key, and then do the following:
a. Press the Bandwidth soft key, and then select the nominal channel bandwidth to be
measured from the following choices:
–
7 MHz (8/7): Sets the channel bandwidth to 7 MHz with sampling factor 8/7. In
conjunction with nominal channel bandwidth
–
8.75 MHz (8/7): Sets the channel bandwidth to 8.75 MHz with sampling factor 8/7
–
10 MHz (28/25): Sets the channel bandwidth to 10 MHz with sampling factor 28/25
b. Toggle the Frame Length soft key and select 5 ms or 10 ms .
c. Press the TTG (RTG) soft key to set the transmit/receive transition gap between the last
sample of the downlink burst and the first sample of the subsequent uplink burst.
d. Enter a value by using the numeric keys, and then press the Enter soft key.
e. Press the CP Ratio soft key, and then select the cyclic prefix ratio option: 1/4 , 1/8 , 1/16 , or
1/32 .
f. Press the DL Symbols soft key to set the number of downlink symbols.
g. Enter a value by using the numeric keys, and then press the Enter soft key.
h. Press the UL Symbols soft key to set the number of uplink symbols.
i. Enter a value by using the numeric keys, and then press the Enter soft key.
3.
Optional . To set the delay, complete the following steps:
a. Press the Delay soft key to set the amount of delay in µs.
b. Enter a value by using the numeric keys. You can also use the rotary knob.