Anritsu Spectrum Master MS2720T, Руководство пользователя

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2-10 Measurements Menu Chapter 2 —Fixed WiMAX Signal Analyzer
2-22 PN: 10580-00236 Rev. D WiMAX MG
Demodulator Menu
Key Sequence:
Measurements
>
Demodulator
Constellation: Press the Constellation submenu key to set the
demodulation to Constellation view. The constellation view shows the
constellation of the demodulated data symbols over one frame. When
demodulation is set to Constellation view, press this submenu key again to
open the Constellation menu.
The constellations are color coded as follows:
• BPSK is shown in orange
• QPSK is shown in purple
• 16-QAM is shown in green
• 64-QAM is shown in yellow
Reference Points: Press this submenu key to display reference
points for the various constellations. On is the default state.
Back: Press this submenu key to return to the Demodulator menu.
Spectral Flatness: Press this submenu key to show the spectral flatness
data that is measured from the preamble at the channel estimation step.
The deviation of the spectral flatness from the average of all the carriers is
shown in dB.
A mask that conforms to the specification is overlaid on the trace. Green
color on the mask indicates pass, and red color on the mask indicates
regions of the mask where the signal fails.
The specification for the mask is:
0 to ±50 subcarriers < ±2 dB
±50 to ±100 subcarriers < +2 dB, and –4 dB
This mask is referenced from the average of all 200 subcarrier amplitude
values. Absolute delta of the power between adjacent subcarriers is
displayed as a numerical value in dB.
Figure 2-18. Fixed WiMAX Demodulator Menu (1 of 2)
Reference Points
Off On
Back
Back
Demodulator
Constellation
Spectral Flatness
EVM vs
Sub Carrier
EVM vs
Symbol
Modulation
Summary
Constellation
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