Anritsu Spectrum Master MS2720T, User Manual

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WiMAX MG PN: 10580-00236 Rev. D 3-1
Chapter 3 — Mobile WiMAX
Signal Analyzer
3-1 Introduction
Anritsu handheld instruments offer Mobile WiMAX Over-the-Air (OTA) measurements,
RF measurements, and Demodulator measurements. OTA Measurements require that an
antenna be attached to the Spectrum Analyzer RF In (50 Ohm) connector on the instrument.
Attach a coupler or attenuator to the same connector to make measurements directly from
the WiMAX BTS transmitter.
3-2 Mobile WiMAX Measurements
The following measurements are made in this mode:
Channel Power (RSSI)
Channel power measures the average time domain power within the selected bandwidth and
is expressed in dBm. Received Signal Strength Indicator (RSSI) is vendor-defined and is often
the same as Channel Power.
Occupied BW
The occupied bandwidth is calculated as the bandwidth containing 99% of the transmitted
power in the span.
Downlink Burst Power
Downlink Burst power is the RMS power over the downlink subframe of the WiMAX frame.
Uplink Burst Power
Uplink Burst power is the RMS power over the uplink subframe of the WiMAX frame.
Preamble Power
Preamble power is the RMS power over the preamble part of the downlink subframe.
Freq Error
The difference between the received frequency and the specified frequency is the frequency
error. Frequency error is displayed in both Hertz (Hz) and parts per million (ppm).
Error Vector Magnitude (EVM)
The Error Vector Magnitude is the ratio in percent of the difference between the reference
waveform and the measured waveform. EVM metrics are used to measure the modulation
quality of a transmitter. Both rms and peak values over the downlink portion are displayed
(the preamble portion is excluded for this measurement).
Caution
The maximum (without damage) input level of the RF In port is +30 dBm. To
prevent damage, always use a coupler or a high power attenuator.
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