Agilent Technologies N9010A, Руководство пользователя

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Chapter 9 69
Modulation Accuracy (Composite EVM) Measurements
Measurement Procedure
Measurement Procedure
Step 1. Press
Mode
,
TD-SCDMA with HSPA/8PSK
to enable the TD-SCDMA with
HSPA/8PSK mode measurements.
Step 2. Press
Mode Preset
to preset the analyzer.
Step 3. Select the signal inputs for the measurement.
For BBIQ measurements this will be the I or I input and the Q or Q
input. Use the procedure in “Using Option BBA Baseband I/Q Inputs.“
Step 4. Press
Input/Output
,
External Gain
,
BTS
and enter the number and
−
dB
according to the external attenuator connected to the analyzer.
Step 5. Press
Mode Setup
,
Radio
,
Device
to toggle the device to
BTS
.
Step 6. Press
Mode Setup
,
Analysis Timeslot
to select the timeslot to be
measured.
Step 7. Press
Meas
,
Mod Accuracy (Composite EVM)
to initiate the modulation
accuracy (composite EVM) measurement.
Step 8. Press
FREQ Channel
,
2
,
GHz
to set the center frequency to 2 GHz.
Step 9. Press
Meas Setup
to check
the keys available to change the measurement
parameters from the default condition.
When you need to estimate the S1/S2 phase on DwPTS, press
Result
Length
and enter the desired value.
Result Length
should be set to a
number no less than 4.
To specify which sub-frame is used for analysis within the acquired
Result Length, press
Analysis Subframe
and enter the desired value.
To adjust the limit parameters, press
Limits
to change the limit lines.
Step 10. Press
View/Display
to select from the following views:
• I/Q Measured Polar Graph
• I/Q Error (Quad view).
• Code Domain Power
• Capture Time Summary
• Numeric Results.
For more information about changing measurement parameters, see
N9079A TD-SCDMA with HSPA/8PSK User’s and Programmer’s
Reference
.
If you have a problem, and get an error message, see the “ Instrument
Messages Guide ”.