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GSM Mobile Measurements
Last updated: May 8, 2002
This section is
not
applicable to GPRS.
The following step-by-step procedures explain how to perform specific measurements available on the GSM Test Application. A detailed description of each measurement is given in the
Reference
information on the documentation CD-ROM and at the Agilent 8960 support website (http://www.agilent.com/find/8960support/).
Setup parameters for each measurement are assumed to be set to their default (Full preset) values unless otherwise stated.
The following measurement procedures are provided:
Measuring Transmit Power
-
Establish a call with the mobile.
-
Press the
Measurement selection
key.
-
Select the
Transmit Power
measurement.
-
Press the
Transmit Power Setup
(
F1
) key.
-
Set the measurement parameters as needed for your measurement situation, including:
Measurement Timeout = 5.0 s
A typical measurement result is shown above.
Press the
CALL SETUP
key and using the
SACCH Reports
window, compare the mobile's reported
Tx Level
with the real measured
Transmit Power
.
Measuring Power versus Time
-
Establish a call with the mobile.
-
Press the
Measurement selection
key.
-
Select the
Power vs Time
measurement.
-
Press the
Power vs Time Setup (
F1
)
key.
-
Press the
Measurement Setup (
F1
)
key.
-
Set the measurement parameters as needed for your measurement situation, including:
Measurement Timeout = 10 s
-
Press the
Measurement Offsets
(
F2
) key.
Note: For statistical analysis the test set allows you to set up to 12 time markers. These markers
do not
define the mask but allow you to obtain measurement results from specified points on the mask.
-
Enter the required time offset values.
Note: Offsets are referenced to bit zero in a normal burst. To obtain results from measurement points before bit zero, enter negative offset values.
-
Press the
Close Menu
(
F6
) key.
The displayed screen shows whether the burst is within the
Mask
(Pass or Fail), broad-band carrier
Transmit Power
, the
Upper Limit Margin
, and the
Lower Limit Margin
.
-
Press the
Return to PvT Control
(
F6
) key.
-
Press the
Change View
(
F2
) key.
-
Press the
Numeric 1 of 2
(
F2
) key to view the measurement results for offsets 1 through 6, or
Numeric 2 of 2
(
F3
) key to view measurement results for offsets 7 through 12.
A typical numeric measurement results screen for offsets 1 through 6 is shown above.
-
Press the
Graph
(
F4
) key to access the full graph of the uplink burst.
A typical full graph view of the burst is shown above. An overall pass/fail indicator is positioned in the bottom left corner of the display:
-
The text "Pass" is shown in a green-colored font if the measurement has passed the entire mask.
-
The text "Fail" is shown in a red-colored font if the measurement has failed any part of the mask.
You can zoom in to individual sections of the graph by pressing the
Full
(
F1
),
Rising Edge
(
F2
),
Falling Edge
(
F3
), or
Useful
(
F4
) keys. In addition, you can control a marker or change axis values by pressing the
Graph Control
(
F5
) key.
A typical graph view of the rising edge of the burst is shown above. You can access this view by pressing the
Rising Edge
(
F2
) key.
In this case, the marker is turned on and positioned on the rising edge. The marker can be turned on by pressing the
Graph Control
(
F5
) key then the
Marker Position
(
F2
) key. Set the required marker position using the knob or the numeric entry keys. The signal level at the marker and its position along the x-axis are shown at the top of the display above the graph.
If you require details on how to navigate through the Power versus Time graph menus, see
Power versus Time Graph Menus
.
Power versus Time Graph Menus
Measuring Phase and Frequency Error
-
Establish a call with the mobile.
-
Press the
Measurement selection
key.
-
Select the
Phase & Frequency Error
measurement.
-
Press the
Phase & Freq. Setup
(
F1
) key.
-
Set the measurement parameters as needed for your measurement situation, including:
Measurement Timeout = 10 s
A typical phase and frequency error measurement result is shown above.
-
Press the
Change View
(
F2
) key.
-
Press the
Graph
(
F2
) key to access the peak phase error graph.
A typical peak phase error graph is shown above.
Two types of pass/fail results are provided:
-
An overall measurement pass/fail indicator is positioned in the bottom left corner of the display:
-
The text "Pass" is shown in a green-colored font if the all of the phase and frequency error measurements (peak phase error, RMS phase error, and frequency error) have passed.
-
The text "Fail" is shown in a red-colored font if any of the phase and frequency error measurements have failed.
-
Individual pass/fail indicators are provided for the peak phase error, RMS phase error, and frequency error. On the display, text labels corresponding to these measurements change color to indicate a pass or fail (green indicates a pass; red indicates a fail).
When the Multi-Measurement Count parameter is set to a number greater than 1, it is possible for some, or all of the individual pass/fail indicators to show a pass while the overall pass/fail indicator shows a fail. This is because the individual pass/fail indicators relate to the last of the multi-measurements made, whereas the overall measurement pass/fail indicator is an accumulative result from all the multi-measurements made.
The marker can be turned on by pressing the
Graph Control
(
F5
) key then the
Marker Position
(
F2
) key. Set the required marker position using the knob or the numeric entry keys. In addition, the axis values can be changed by pressing the
Axis Control
(
F1
) key. This allows you to zoom in or out to look at particular sections of the graph in more detail.
A typical peak phase error graph is shown above. This graph is zoomed in to show bits ranging from 100.0 to 120.0 at a 1.0 degrees per division setting. The Y-axis reference point is changed to 5.0 degrees.
In this case, the marker is turned on and positioned at bit 112. The phase error at the marker and its bit position are shown at the top of the display above the graph.
If you require details on how to navigate through the phase and frequency error graph menus, see
Phase and Frequency Error Graph Menus
.
Phase and Frequency Error Graph Menus
Measuring Fast Bit Error
To make fast bit error measurements your mobile must be fitted with a Test SIM card.
-
Establish a call with the mobile.
-
Press the
Measurement selection
key.
-
Select the
Fast Bit Error
measurement.
You should hear a warbling sound from the mobile's loudspeaker. This is the PRBS-15 data which the test set sends to the mobile.
-
Press the
Fast Bit Error Setup
(
F1
) key.
-
Set the measurement parameters as needed for your measurement, including:
Measurement Timeout = 13.0 s
To see the effect of cell power on fast bit error rate, press the Cell Power (
F7
) key and slowly reduce the power while observing Fast Bit Error display.
Measuring Bit Error
To make bit error measurements your mobile must be fitted with a Test SIM card.
-
Establish a call with the mobile.
-
Press the
Measurement selection
key.
-
Select the
Bit Error
measurement.
-
Press the
Bit Error Setup
(
F1
) key.
-
Set the measurement parameters as needed for your measurement situation, including:
Measurement Timeout = 13.0 s
The display shows the bit error rate measurement and depending on the loopback type selected (A residual or B non-residual), either a frame erasure (FER) or cyclic redundancy check (CRC) measurement.
To see the effect of cell power on Bit Error Rate, press the
Cell Power
(
F7
) key and slowly reduce the power while observing the Bit Error display.
Measuring Output RF Spectrum
-
Establish a call with the mobile.
-
Press the
Measurement selection
key.
-
Select the
Output RF Spectrum
measurement.
-
Press the
ORFS Setup
(
F1
) key.
-
Press the
Measurement Setup
(
F1
) key.
-
Set the measurement parameters as needed for your measurement, including:
Measurement Timeout = 20 s.
-
Press the
Modulation Frequencies
(
F2
) key and set up your required offset frequencies for ORFS due to modulation.
-
Press the
Switching Frequencies
(
F3
) key and set up your required offset frequencies for ORFS due to Switching.
-
Press the
Close Menu
(
F6
) key.
-
Press the
Return to ORFS Control
(
F6
) key.
-
Press the Change View (
F2
) key.
-
Press the
Modulation Numeric 1 of 3
(
F1
) key.
The measurement results for the first eight positions in the ORFS due to modulation table are displayed. You can view the results for the remaining 14 positions by pressing the
Modulation Numeric 2 of 3
(
F2
) key or the
Modulation Numeric 3 of 3
(
F3
) key. Note that the results are in dB relative to the 30 kHz BW Power shown on the screen.
-
Press the
Switching Numeric
(
F4
) key to display the measurement results for ORFS due to switching.
A typical measurement results screen for ORFS due to switching is shown above.
-
Press the
Graph
(
F5
) key then the
Modulation
(
F1
) key to access the ORFS due to modulation bar graph.
A typical ORFS due to modulation graph is shown above. On the display, the bar representing each offset is shown in yellow and the center frequency is indicated by a white vertical line. There are two limit lines displayed; the absolute limit line is green and the relative limit line is blue. The pass/fail result is relevant to the displayed measurement.
-
Press the
Switching
(
F2
) key to access the ORFS due to switching bar graph.
A typical ORFS due to switching graph is shown above. On the display, the bar representing each offset is shown in blue and the center frequency is indicated by a white vertical line.
In this case, the marker is turned on and positioned at the 600 kHz offset. The signal level and frequency of the offset where the marker is positioned, are shown at the top of the display above the graph.
The marker can be turned on by pressing the
Graph Control
(
F5
) key then the
Marker Position
(
F2
) key. Set the required marker position using the knob or the numeric entry keys. In addition, the axis values can be changed by pressing the
Axis Control
(
F1
) key. This allows you to zoom in or out to look at particular sections of the graph in more detail.
-
Press the
Modulation and Switching
(
F3
) key to access a screen displaying both graphs, as shown in the example below.
Note that each of the graphs have their own graph controls on
F4
and
F5
.
Any failing results are displayed in red.
If you require details on how to navigate through the Output RF Spectrum graph menus, see
Output RF Spectrum Graph Menus
.
-
To set your own limits for each offset use the Measurement Setup menu and set
Limit Source
to
Manual
. You can then use
Modulation Limits
(
F4
) and
Switching Limits
(
F5
) to set your required limits for each offset.
Output RF Spectrum Graph Menus
Measuring IQ Tuning
This measurement can only be performed with your mobile in test mode and transmitting either all ones or all zeros.
-
Press the
Measurement selection
key.
-
Select the
IQ Tuning
measurement.
-
Press the
More
key (bottom right) to obtain the Call Parms (3 of 4) screen.
-
Press the
Receiver Control
(
F7
) key and select
Manual
.
-
Press the (
F11
) key and set the expected power level from your mobile.
-
Press the
IQ Tuning Setup
(
F1
) key.
-
Set the measurement parameters as needed for your measurement, including:
Multi-Measurement Count = 50
Trigger Source = Immediate
-
Switch on your mobile and set it to transmit a series of all zeros.
The results are displayed on the IQ Tuning screen. Notice that when the mobile is transmitting a series of all zeros the carrier offset is at +67.708 kHz.
-
Change the settings on the mobile to transmit a series of all ones.
The results are displayed on the IQ Tuning screen. Notice that when the mobile is transmitting a series of all ones the carrier offset is at -67.708 kHz.
-
Press the
Graph
(
F2
) key to access the IQ Tuning bar graph.
A typical IQ Tuning graph is shown above. On the display, the bar representing each offset and the carrier frequency (Fc) is shown in yellow.
If you require details on how to navigate through the Output RF Spectrum graph menus, see
IQ Tuning Graph Menus
.
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