Page 44 - EngineerIT November 2021

RADIO COMMUNICATION

the same PLL (either one or two) and the same hop tables and TDD this restriction can be removed.
timing configurations. The MCS capability provided by the ADRV9002 ADRV9002 tracking calibrations are usually not performed during
could be enabled to ensure that multiple channels on the same fast FH. However, the initial calibrations are performed based on
or different ADRV9002 devices are fully synchronised with each multiple frequency regions according to users’ FH configurations to
other with deterministic latency. Phase synchronisation can also be achieve the best possible performance.
achieved through MCS, which is performed each time PLL retunes
frequency. With MCS, multiple channels could achieve synchronicity FH performance evaluation using ADRV9002 transceiver
even during FH, making the ADRV9002 an attractive solution for evaluation software (TES)
MIMO diversity applications involving FH. More detailed descriptions FH performance can be evaluated thoroughly through the ADRV9002
regarding the requirements and limitations of using MCS during FH TES with the evaluation board. Both the Xilinx® ZC706 and ZCU102
can be found in the ADRV9001 System Development User Guide. 2 FPGA boards are supported by TES.(2) As shown in Figure 11, the
For channel multiplexing, each pair of channels uses one PLL and FH configuration pages are easy to use to configure FH parameters,
performs FH independently from each other. One limitation is that the very including FH operation mode, the hopping tables, the GPIO setting, the
fast FH, which requires two PLLs for a pair of transmit and receive channels, TDD timing, etc. FPGA synchronisation features are built into the TES
can’t be applied for channel multiplexing with one ADRV9002 device. to allow users to accurately control the TDD timing so that the transmit
Besides 2T2R mode, it is worth mentioning that the ADRV9002 or receive frames can be fully synchronised with hop frames. Many FH
also supports 1T2R and 2T1R operations for FH, which provides examples are also provided in TES for users to further explore.
greater flexibility to meet users’ specific requirements.
Conclusion
Support of FH with DPD operation FH is one of the advanced system features provided by the next-
The ADRV9002 also supports DPD operation for both narrow-band and generation SDR transceiver, the ADRV9002. With two PLLs, multiple
wide-band applications. It corrects the non-linearity of the power amplifier FH modes, and flexibility in loading and indexing hop tables, the
(PA) to significantly improve PA efficiency while achieving standard ADRV9002 empowers users with great FH capabilities to handle various
compliant adjacent channel power leakage ratio (ACPR) performance. applications and achieve advanced system requirements. All features
One advanced feature of the ADRV9002 is that DPD can be can be thoroughly evaluated through the ADRV9002 TES and Software
performed together with FH. In such a case, the ADRV9002 allows Development Kit (SDK). n
users to configure up to eight frequency regions, and the DPD
algorithm creates an optimal solution for each frequency region. A For more information on Analog Devices contact Conrad Coetzee at
DPD solution as a set of coefficients can also be stored and loaded at ccoetzee@arrow.altech.co.za
the end and the beginning of a transmission, respectively, for each
region. This ensures PA linearity for the entire hop frequency range. References
Since DPD is an adaptive filtering process that must capture a 1. John G. Proakis. Digital Communications, 3rd edition. McGraw-Hill, March 1994.
set of samples periodically for coefficient computation, the hopping 2. UG-1828: ADRV9001 System Development User Guide. Analog Devices, Inc.,
December 2020.
frame length needs to be sufficiently long to satisfy the DPD capture 3. Kao Chin-Han. “Performance Analysis of a JTIDS/Link-16-Type Waveform
length requirement. However, in cases when users only utilise the Transmitted over Slow, Flat Nakagami Fading Channels in the Presence of
initially loaded DPD coefficients without the need for DPD updates, Narrowband Interference.” Naval Postgraduate School, 2008.

About the Author
Mizhou (Michelle) Tan is a product
applications engineer with Analog
Devices. She has supported
the design and development
of RF transceiver products and
applications for about three years.
Prior to joining ADI, she received her
B.S. and M.S degrees in electrical
engineering from Sichuan University
in China and her Ph.D. degree in
electrical and computer engineering
from New Jersey Institute of
Technology in 2004. After that, she
worked as an algorithm, system and
software engineer in Agere Systems,
LSI Logic, and Intel Corp. from
2004 to 2018. She has published
more than 15 papers in technical
conferences and journals and owns
nine issued patents in wireless
communication and digital signal
processing area. She can be reached
at mizhou.tan@analog.com.
Figure 11: Configure FH through TES.

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