Spectrum Analyzer Measurement Guide : Spectrum Analyzer : Adjacent Channel Power Measurement
Adjacent Channel Power Measurement
Required Equipment
30 dB, 50 watt, Bi‑Directional, DC–18 GHz, N(m)–N(f) Attenuator, Anritsu Part Number 42N50A‑30 (if required for the power level being measured)
Test Port extension cable, Anritsu Part Number 15NNF50‑1.5C
1. Using the test port extension cable and 30 dB attenuator, connect the signal source to the input of the attenuator, and connect the output of the attenuator to the RF In test port.
2. If an attenuator was connected in step 1, press the Amplitude main menu key then press the RL Offset submenu key, enter 30 then select dB External Loss to compensate for the loss in the attenuator.
3. Press the Amplitude main menu key and press the Reference Level submenu key to set the reference level to 60 dBm.
4. Press the Atten Lvl submenu key to set the input attenuation level needed for the measurement. This value depends on the input power level and any external attenuator. Enter an attenuation level to achieve roughly –40 dBm at the input mixer.
5. Press the BW main menu key and verify that Auto RBW and Auto VBW are On.
6. There are two ways to set the measurement parameters. If the signal standard and channel are known, press the Freq main menu key and set the signal standard and press Channel submenu key for the signal to be measured, then skip to Step 12. If the signal standard and channel are not known, follow the procedure in Step 7 through Step 11.
7. Press the Freq main menu key, press the Center Freq submenu key, and enter the desired center frequency.
8. Press the Shift key then the Measure (4) key. Then press the Power and Bandwidth submenu key, and press the ACPR submenu key.
9. Press the Main Ch BW submenu key, and enter the main channel bandwidth.
10. Press the Adj Ch BW submenu key, and enter the adjacent channel bandwidth.
11. Press the Ch Spacing submenu key, and enter the channel spacing.
12. Make the measurement by pressing the On/Off submenu key. The detection method is automatically changed to RMS Average.
Solid vertical lines are drawn on the display to indicate the main channel. Dashed vertical lines define the adjacent channels. The SPA displays the measurement results in the message area.
Adjacent Channel Power Ratio is a constant measurement. After it is turned on, it remains on until it is turned off by pressing the On/Off submenu key again.