Adrv9001 Dpd Supported Waveforms - Analog Devices ADRV9001 User Manual

Preliminary Technical Data
In the ADRV9001 device, DPD is considered as one of the transmit (Tx) tracking calibrations. It is a real-time signal processing with
iterative updates to account for hardware variations such as temperature and power level changes. Similar to some other Tx tracking
calibrations, it requires a loopback path from the Tx to the Observation Rx (ORx) to perform the calibration. In this case, an external
loop back path (ELB) type 2 is required (please refer to Rx/ORx Signal Chain section for more details about the loopback paths), in
which, the Tx output signal after power amplifier is looped back to the ORx as shown in Figure 141. The user must make sure this path is
established before enabling the integrated DPD. In FDD applications where only one Rx is used or in the TDD applications during Tx
time slots, unused Rx can be used to perform DPD calibration as well as some other Tx tracking calibrations. Please refer to ADRV9001
Example Use Cases section for more details.
ADRV9001
Tx DATA
ACTUATOR
COEFFICIENTS
CALCULATION
ENGINE
Similar as shown in Figure 55 ADRV9001 DPD includes 2 major components, a "DPD Actuator" and a "Coefficients Calculation
Engine". The "Coefficients Calculation Engine" computes the DPD coefficients periodically and then updates the "DPD Actuator" for
real-time pre-distortion of the transmit signal. The pre-distortion coefficients are associated with polynomial terms defined by the power
amplifier model. In order to meet the real-time processing requirement, polynomial terms that are associated with a common time-delay
input data are pre-computed and stored into Look-up Tables (LUT) in the "DPD Actuator". In the device, without frequency hopping, 2
LUTs are used for all waveforms, one is currently being active for performing pre-distortion while the other one is being updated at the
background to track the changes and replace the current LUT when ready, resulting in seamless transmit operation. "DPD Actuator" also
includes a functionality to perform the calculation of the amplitude of the input signal, which is used to search the LUT. The outputs of
the LUT are then multiplied with different time delayed input data according to the configured DPD model and combined to form the
final pre-distorted transmit data.

ADRV9001 DPD SUPPORTED WAVEFORMS

The integrated DPD supports NB waveforms such as TETRA. Note some NB standard waveforms such as Direct Modulation types with
constant envelope do not require DPD. The different modes of operation for TETRA are listed in Table 69. The integrated DPD supports
all TETRA 1 and 2 modes.
INPUT
t
DATA, d( ) INPUT, x(
PREDISTORTOR
FREQUENCY
FREQUENCY
Figure 140. High Level Block Diagram of DPD Algorithm
DAC
Tx ANALOG FRONT END
DPD
DAC
ADC
ORx ANALOG FRONT END
ADC
DPD
Figure 141. High level Block Diagram of ADRV9001 DPD Implementation
COMPRESSION
INPUT
t
) OUTPUT, y(
PA
DPD
COEFFICIENTS
COMPUTAION
+ BALUN
LO
SYNTHESIZER
BALUN
LO
SYNTHESIZER
Rev. PrA | Page 163 of 253
INPUT
t
)
FREQUENCY
ANTENNA
DIRECTIONAL
COUPLER
DUPLEXER
POWER
AMPLIFIER
ELB TYPE 2
UG-1828