Analog Devices ADRV9005 Reference Manual page 242

Reference Manual ADRV9001
DIGITAL PREDISTORTION (DPD)
detectionPeakThreshold
It detects a valid data capture for the DPD/CLGC operation if a specified number of samples (countsGreaterThanPeakThreshold) is greater
than the defined peak threshold. The DPD/CLGC operation needs a good set of large signal samples to properly model the PA compression
behavior.
countsLessThanPowerThreshold
It defines the number of samples below the detectionPowerThreshold to determine an invalid capture. To disable it, set it to be the DPD/CLGC
maximum number of capture samples of 4096.
countsGreaterThanPeakThreshold
It defines the number of samples greater than the detectionPeakThreshold to determine a valid capture. To disable it, set it to 0.
immediateLutSwitching
When a new DPD solution is formed, load the new solution into a spare LUT, which can then be switched with the active LUT. There are two
options for LUT switching. When immediateLutSwitching is set to "TRUE", the new LUT immediately, when ready, swaps out the active LUT.
When immediateLutSwitching is set to "FALSE", after the updated LUT is available, LUT swapping is triggered after the next data frame is
completed. Note: This only applies to TDD operations. FDD systems should always use immediate LUT switching.
useSpecialFrame
To achieve optimal performance, DPD must capture the peaks of the signal. Some standards allow the transmission of special data used for
DPD estimation. In other cases, the baseband processor can know in advance that a frame contains good data for DPD estimation. In these
cases, the user can control which frames are used for DPD. The flag indicates the control of the frames that the DPD can capture. This is
currently not supported. So, it should be disabled.
resetLuts
To start the DPD operation from a known state, reset the LUTs. By setting resetLuts to 1, it sets most polynomial terms to 0 to remove the
predistortion at the beginning of the DPD operation.
timeFilterCoefficient
This parameter defines the coefficient of a single-pole filter, which mitigates the spectral spikes caused by LUT switching, especially in the FDD
and narrowband use cases. Avoid spectral spikes in TDD by not performing an immediate LUT switch. The range of "timeFilterCoefficient" is
between 0 and 1. If setting it to 0, it is equivalent to disabling this functionality. Experiment with this parameter and pick the optimal value to
reduce the spikes. Note that enabling this feature might hurt the convergence time. The bigger this parameter is, the slower the convergence
might be. Therefore, consider this method as an available tool when all other methods are exhausted and employ it with caution.
dpdSamplingRate_Hz
This parameter shows the sampling rate in Hz for the DPD actuator and capture. It is read only and does not have any effect on DPD
configurations.
clgcLoopOpen
This parameter opens or closes the gain control loop. When it is set to 1, the transmit attenuators are not updated. This measures the gain to
help determine the target gain. Once the target gain is set, set it to 0 to close the loop and start the CLGC operation.
clgcGainTarget_HundredthdB
Configure this parameter to notify the ADRV9001 about the gain target for CLGC with an accuracy of a hundredth of a dB.
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