Performing a Basic Spectrum Emissions Mask Measurement

Performing a Basic Spectrum Emissions Mask Measurement

Step
Notes

1
Select Spectrum Analyzer.

Mode

[Spectrum Analyzer/Tools]
[Spectrum Analyzer]

2
Enter the channel standard.

[Chan Std]
Select the standard using the up and down arrow buttons.
[Select]
On [Units] select Chan.
Each time you press the [Units] menu key, the selected option changes.

3
Enter the channel number.

[Channel]
Enter the channel number using the numeric keypad.
Select [Fwd] or [Rev].

4
Select the SEM measurement.

[Measurements]
[SEM]

5
Switch the SEM measurement On.

[SEM]
Each time you press the [SEM] menu key, the selected option changes.
As soon as you switch the SEM measurement On, the SEM mask (a stepped yellow line) will appear on the screen. If no SEM mask appears, check that SEM measurements are supported for your selected channel standard.
CDMA or 1xEV-DO signals only: Each individual mask line segment will be annotated with either a green circle with 'P' inside it (indicating that the limit line segment has not been exceeded) or with a red triangle with an 'F' (indicating the limit has been exceeded and the test has failed).
WCDMA UTRA signals only: The green circles with "P" (for a pass) and the red triangles with "F" (for a fail) are not displayed on WCDMA SEM measurements. Instead, if any segment of the mask fails, the limit line segment in question will thicken, and will change from yellow to red and white.

6
Switch Noise Correction On or Off according to your needs (W-CDMA channel standard only).

[Noise Corr]
Each time you press the [Noise Corr] menu key, the selected option changes.
Noise Correction only takes effect when measuring W-CDMA channel standards. There is no Noise Correction for any other channel standards.
Agilent Technologies recommends that at leaast 10 averages should be used when Noise Correction is being used.

When the SEM Measurement is turned On, the states of the following parameters are stored for restoration when the SEM Measurement is turned Off:

Resolution bandwidth mode
Frequency span
Averaging mode
Number of averages
Upper limits
Lower limits
The following parameters are then set to perform the measurement. Each time the SEM measurement is turned On, these parameters are set to the values as detailed below. In addition the upper limits are reset to appropriate default values when the SEM measurement is On and the selected channel standard is changed.
Occupied bandwidth measurement turned Off
Interference analysis measurement turned Off
Resolution bandwidth mode set to Manual
Resolution bandwidth set to 30 kHz
Lower limit center, segment 1 and segment 2 set to Off
Number of averages set to 10
Averaging mode set to
- Running for CDMA and 1xEVDO channel standards
- Group Average for W-CDMA channel standard
If currently selected channel standard is Band class 0, 2, 3, 5, 7, 9 or 10 (see table above)
- Span set to 8 MHz
If currently selected channel standard is Band class 1, 4, 6 or 8
- Span set to 5 MHz
Upper limits are set to the levels specified in the table above.
The SEM Measurement is turned Off when either the Occupied Bandwidth or Interference Analysis measurements are turned On.

NOTE: The SEM standards for W-CDMA signals specify different RBW settings at different frequency offsets (see "W-CDMA UTRA Channel Frequencies and Emission Limits"). This requires your base station test set to build up the W-CDMA SEM trace from several discrete segments, and can make the test set appear slow. The progress of your W-CDMA SEM measurement is indicated by the following status messages:

Measuring SEM Outer Segments...
Measuring SEM Inner Segments...
Measuring reference Channel...

NOTE: Note also that if you have Noise Correction switched On, your test instrument needs to take two sweeps for every update. This will make your test intrument cycle through the three progress messages (above) twice before the screen is updated.


	Step	Notes
1	Select Spectrum Analyzer. Mode [Spectrum Analyzer/Tools] [Spectrum Analyzer]
2	Enter the channel standard. [Chan Std] Select the standard using the up and down arrow buttons. [Select] On [Units] select Chan.	Each time you press the [Units] menu key, the selected option changes.
3	Enter the channel number. [Channel] Enter the channel number using the numeric keypad. Select [Fwd] or [Rev].
4	Select the SEM measurement. [Measurements] [SEM]
5	Switch the SEM measurement On. [SEM]	Each time you press the [SEM] menu key, the selected option changes. As soon as you switch the SEM measurement On, the SEM mask (a stepped yellow line) will appear on the screen. If no SEM mask appears, check that SEM measurements are supported for your selected channel standard. CDMA or 1xEV-DO signals only: Each individual mask line segment will be annotated with either a green circle with 'P' inside it (indicating that the limit line segment has not been exceeded) or with a red triangle with an 'F' (indicating the limit has been exceeded and the test has failed). WCDMA UTRA signals only: The green circles with "P" (for a pass) and the red triangles with "F" (for a fail) are not displayed on WCDMA SEM measurements. Instead, if any segment of the mask fails, the limit line segment in question will thicken, and will change from yellow to red and white.
6	Switch Noise Correction On or Off according to your needs (W-CDMA channel standard only). [Noise Corr]	Each time you press the [Noise Corr] menu key, the selected option changes. Noise Correction only takes effect when measuring W-CDMA channel standards. There is no Noise Correction for any other channel standards. Agilent Technologies recommends that at leaast 10 averages should be used when Noise Correction is being used.