IEEE Solid-States Circuits Magazine - Fall 2022 - 31

Matlab's Communications Toolbox and
repeatedly transmitted through the PA
test chip using the AD9082 RF transceiver
board. Each BLE packet recorded
in the presented dataset was transmitted
over BLE channel 37 (2,402 MHz)
using the LE1M physical-layer mode.
Measurement Setup
and Data Processing
The dataset was captured using an
AD9082-FMCA-EBZ direct RF sampling
transceiver board as a receiver, with
the onboard RF DAC used to drive
the reconfigurable PA. Baseband I/Q
samples were directly fetched at a
sampling rate of 250 MSPS from the
AD9082-FMCA-EBZ using the Analog
Devices High Speed Converter Toolbox
for Matlab, after being sampled
at 6 GSPS by the RF ADC and passing
through the on-chip digital downconverter
and decimation filters. These
were further decimated to a sampling
rate of 25 MSPS in Matlab to lower the
required storage space. A USB-6001
NI DAQ was used to generate the control
signals necessary to switch the
PA between configurations. Sufficient
samples were collected for each PA
configuration to contain more than
1,000 received BLE packets. An image
of the measurement setup is shown
in Figure 4(a). Figure 4(b) illustrates
the connections of the different
components used in the measurement
setup. The power spectra of
the PA output while transmitting
the BLE packets are plotted in Figure
5 across 220 PA configurations.
It can be seen from the figure that
there is a ±2-dB variation across all
220 configurations.
The I/Q samples corresponding
to actual BLE packets were extracted
from the fetched data using cross
correlation with the known BLE preamble
sequence to determine the
starting indices of the packet. Afterward,
demodulation was performed
to verify the integrity of each packet
in the dataset.
Recorded Data Analysis
Recordings were captured of the
transmitted BLE packets across all
220 PA configurations using the setup
described in the section " Reconfigurable
PA and Dataset Collection. "
Enough I/Q samples were taken to
collect more than 1,200 packets for
each PA configuration at a baseline
SNR of 35 dB. Later, an attenuator in
the measurement setup was used to
lower the signal power, and sufficient
samples were taken to collect more
NIDAQ
AD9082FMCA-EBZ
Reconfigurable
PA
(a)
NI-DAQ
DAC
FPGA
for
Controlling
ADC
(b)
FIGURE
4: (a) The AD9082-FMCA-EBZ board was used as a direct conversion receiver with
DDC and as a transmitter to drive the PA. An NI DAQ USB-6001 is used to generate the
control signals for sweeping across the PA configurations. (b) The block diagram of the
connections of the different components used in the measurement setup.
-20
-30
-40
-50
-60
-70
-80
-90
2.398
2.4 2.402
Frequency (GHz)
2.404 2.406
FIGURE 5: The power spectra of the PA output while transmitting the BLE packets were
measured across PA configurations with a spectrum analyzer. The different colored lines
are used to indicate the power spectrum for each of the 220 combinations.
IEEE SOLID-STATE CIRCUITS MAGAZINE
FALL 2022
31
AD9082
PA
Power (dBm)
Rx Link
Tx Link
IEEE Solid-States Circuits Magazine - Fall 2022

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