Measuring The Clgc Target Gain - Analog Devices ADRV9005 Reference Manual

Reference Manual
DIGITAL PREDISTORTION (DPD)
1: adi_adrv9001_cals_ExternalPathDelay_Calibrate(). Call this API when the channel state is CALIBRATED. It internally calls the following
functions (no need to call these two lower level APIs).
ExternalPathDelay_Run(), which runs external path delay calibrations.
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ExternalMinusInternalPathDelay_Measure(), which measures and gets the result of the difference in the path delays between the ILB and
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ELB and calculates the delay.
2: adi_adrv9001_cals_ExternalPathDelay_Set(). This API sets the external path delay value measured by "adi_adrv9001_cals_External-
PathDelay_Calibrate()." Call this API when the channel state is in STANDBY and CALIBRATED only.
3: adi_adrv9001_cals_ExternalPathDelay_Get(). It gets the current external path delay value. Use this API to check the delay.
DPD Monitoring
Use DPD monitoring to check the running operation and status of the DPD process. Use the adi_adrv9001_dpd_channel_Status_Get() API to
retrieve the DPD status for Channel 1 or Channel 2.
The following status and power measurements can be retrieved via the API:
Number of iterations—the count of times the DPD process has started a capture
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Number of Successful iterations—the count of times the DPD process has completed and processed a capture successfully
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Tx Peak/RMS Power—the peak and average output power
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Rx Peak/RMS Power—the peak and average ORx input power
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An example status from the TES GUI is shown in

MEASURING THE CLGC TARGET GAIN

The user is responsible to set the gain target for the choice of PA. Determine the gain target in the lab using a PA with a typical gain at
room temperature. The following guidelines provide the optimal operation of the ADRV9001. Fix the optimal gain target and adjustable gains in
transmit and external loopback receive during operation, except for the transmit attenuation adjustment by the CLGC.
1. Set the transmit frequency to the middle of the band of interest.
2. Adjust the peak digital transmit signal amplitude to be between −6 dBFS at the DAC.
Margin 3 dB
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Maximum DPD expansion 3 dB
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3. Adjust the transmit attenuator so the PA input ACPR (before power amplifier) is about −70 dBc.
4. Connect the amplifier drivers and PA to the RF output.
5. Increase the transmit attenuation so that the peak compression is about 1 dB.
6. If a peak compression of 1 dB cannot be reached, increase the gain of a PA.
7. Adjust the gain of the external loopback path to make the feedback signal peak amplitude to around -18 dBm with a tolerance of ±5 dB.
8. Do not change these settings during normal operation. Otherwise, a new gain target has to be determined.
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Figure 228.
Figure 228. Example DPD Monitor Status
ADRV9001
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