Anritsu S331C - Manual (Page 66)

Chapter 5
Spectrum Analyzer
Measurements
Introduction
This chapter provides a description of field measurements available when the Model S114C
or S332C Site Master is in Spectrum Analyzer mode.
Occupied Bandwidth
A common measurement performed on radio transmitters is that of occupied bandwidth
(OBW). This measurement calculates the bandwidth containing the total integrated power
occupied in a given signal bandwidth. There are two different methods of calculation de-
pending on the technique to modulate the carrier.
q 99% Method — The occupied frequency bandwidth is calculated as the bandwidth
containing 99% of the transmitted power.
q X dB Down Method — The occupied frequency bandwidth is defined as the band-
width between the upper and lower frequency points at which the signal level is X
dB below the peak carrier level.
Required Equipment
q Site Master Model S114C or S332C
q 30 dB, 50 Watt, bi-directional, DC –18 GHz, N(m) – N(f), Attenuator, 42N50A-30
q Test Port extension cable, Anritsu 15NNF50 – 1.5C
Procedure
Step 1. Using the test port extension cable and 30 dB attenuator connect the Site Master
to the RF_Out test port.
Step 2. Press the ON/OFF key on the Site Master.
Step 3. Press the MODE key.
Step 4. Use the Up/Down arrow key to select the Spectrum Analyzer mode and press
ENTER .
Step 5. Enter the center frequency of the measurement.
Step 6. Select the appropriate frequency span, reference level, input attenuation level,
resolution bandwidth, and video bandwidth.
Step 7. Press the MEAS key.
Step 8. Press the OBW soft key.
Step 9. Select measurement method, % or dBc down by pressing the corresponding soft
key and press ENTER .
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