How is a TX Dynamic Power Measurement Made?
The TX dynamic power measurement aids in power calibration of your UE. The measurement is not performed with a call established between the test set and UE. Rather, you must place your UE into a test mode which forces it to transmit a power sequence of successive down steps of fixed size and duration.
The UE's output power sequence may span some or all of the measurement's input range of -61 dBm to +28 dBm, in up to 99 steps. The steps may be 20, 40 or 80 ms in duration.
Before starting the TX dynamic power measurement, you must use
Manual Receiver Control
to specify the initial transmit power of the UE's power sequence to properly range the test set's receiver. You must also specify the UE's transmit frequency (see
Measurement Frequency
).
Example UE Output Power Profile for TX Dynamic Power Measurement
The UE must trigger the measurement with a positive change in power from 20 dB below the initial transmit power. To ensure successful triggering, it is recommended that you first order the UE to transmit continuously at the initial transmit power level, initiate the measurement, then order the UE to drop and then raise its output power by more than 20 dB to create the RF rise trigger.
Once triggered, the TX dynamic power measurement performs a series of channel power measurements, one at each step of the power sequence. Before measuring the power level of step 0, the test set tunes its receiver according to the
Manual Power
setting. The test set then tunes its receiver to the proper level before performing each subsequent channel power measurement based on the
Power Step Size
setting and the measured power of the prior step (this allows the measurement to track UEs that do not correctly decrease power according to the
Power Step Size
setting). The UE must step its power down and then hold its power constant for each step in the test sequence (the step duration is determined by
Power Step Time
). After completing a measurement at each of the requested power steps (based on the
Number of Power Steps
setting), the test set returns power results for the initial UE transmit power (step 0), and for each of the steps.
Required Initial Conditions
While in
FDD Test
,
Active Cell
and
Cell Off
operating modes,
Power Control
must be set to
Manual
. You must then set
Manual Power
(or
Expected CW Power
if in
CW
operating mode) to the initial transmit power of the sequence.
You must set
Measurement Frequency
to the UE's transmit frequency.
You must set
Power Step Size
,
Power Step Time
and
Number of Power Steps
to match the power sequence to be transmitted by the UE.
Operating Considerations
The TX dynamic power measurement must re-range and re-trigger for every step in the UE's power sequence. To ensure that this process is not interrupted by other operations, it is recommended that you not send any GPIB commands to the test set or press any front panel keys until the measurement has completed. If the measurement misses a trigger, it aborts and returns
Integrity Indicator
30
:
Missed Trigger
.
The TX dynamic power measurement is available in all operating modes. However, it is assumed that the call status is idle as the UE must be operating in a test mode to transmit the required power sequence.
No other measurements can be running when a TX dynamic power measurement is performed. If any measurements are running when a TX dynamic power measurement is initiated, they are closed and a message is displayed to indicate that they were closed. Likewise, if any other measurements are initiated while a TX dynamic power measurement is running, the TX dynamic power measurement is closed and a message is displayed.
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