CML Microcircuits DE9941A User manual

DE9941A
Advanced SDR Demonstrator
User Manual
2020 CML Microsystems Plc 16 April 2020
UM9941A/1 April 2020 USER MANUAL Advance Information
Features
Demonstration of SDR wireless data modem supporting multiple
bit rates and modulation schemes
Provides a demonstration platform for the
CMX7364 Multi-mode HighPerformance Wireless
Data Modem
Direct Conversion Receiver (CMX994E) and Cartesian Feedback
Loop Transmitter (CMX998)
On-board PLL and VCO for 350 to 400 MHz
Operation
1W Transmitter Operation
On-board STM32 ARM microcontroller and script
handler + USB interface
Designed to meet EN 302 561 / EN 300 113
Small size –87mm x 55mm
1Brief Description
The DE9941A is a smalldemonstration platform for the CMX994E Di rect Conversion Receiver, the CMX998 Cartesian Loop
Transmitter andthe CMX7364Multi-mode High Performance Wireless Data Modem. The small form factor of the
demonstration/evaluation platform is possible due to the compact nature of the CML IC solutions. The DE9941A can be
us ed to demonstrate Tx and Rx performance with multi-level QAM, FSK and GMSK type modulation. Together with the
on-board ARM host controller, a full transceiver can be demonstrated using a Function Imageand control scripts.
The DE9941A provides a Fractional-N PLL and VCO to provide local oscillator signals for the CMX994E and CMX998. The
on-board ARM microcontroller, together with the control scripts, gives the user the abilityto programthe RF synthesiser
to the correct operating frequencies. The design also includesa 1W power amplifier, harmonic filter and Tx/Rx switch.
The RF performance is designed to be compliant with EN 302 561 / EN 300 113 and all the circuits are provided with
power-down capability to allow standby functionality.
The design is aimed to be low cost, with a minimum number of component types/values.

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CONTENTS
Section Page
1Brief Description.................................................................................................................................................................1
2Block Diagram.....................................................................................................................................................................4
3Preliminary Information .....................................................................................................................................................5
3.1 Laboratory Equipment.........................................................................................................................................................5
3.1.1 Power Supply.......................................................................................................................................................................5
3.2 Handling Precautions ..........................................................................................................................................................5
3.2.2 Contents - Unpacking..........................................................................................................................................................5
3.3 Approvals.............................................................................................................................................................................5
4Quick Start...........................................................................................................................................................................6
4.1 Setting-Up............................................................................................................................................................................6
4.1.1 ES9941A Software and Driver Installation ..........................................................................................................................7
4.2 Configuration.......................................................................................................................................................................8
4.2.1 Tx Configuration..................................................................................................................................................................8
4.2.2 Rx Configuration..................................................................................................................................................................8
4.3 Operation ............................................................................................................................................................................8
5Signal Lists...........................................................................................................................................................................9
6Circuit Schematics and Board Layouts .............................................................................................................................10
7Detailed Description .........................................................................................................................................................11
7.1 Hardware Description .......................................................................................................................................................11
7.1.1 Harmonic Filter..................................................................................................................................................................11
7.1.2 Tx/Rx Switch ......................................................................................................................................................................11
7.1.3 Coupler..............................................................................................................................................................................11
7.1.4 Power Amplifier.................................................................................................................................................................11
7.1.5 Transmitter........................................................................................................................................................................11
7.1.6 Receiver.............................................................................................................................................................................12
7.1.7 Local Oscillator..................................................................................................................................................................12
7.1.8 Reference Oscillator..........................................................................................................................................................12
7.1.9 Power Supply.....................................................................................................................................................................12
7.1.10 Inductors............................................................................................................................................................................12
7.1.11 Adjustments and Controls External/Internal LO...............................................................................................................12
7.2 Software Description.........................................................................................................................................................12
7.3 Application Information ....................................................................................................................................................12
7.3.1 GUI Description .................................................................................................................................................................12
7.3.2 Function Image Load .........................................................................................................................................................13
7.3.3 Scripts Handler Tab ...........................................................................................................................................................13
7.3.4 Typical Receiver Results with CMX7364 FI-4 ....................................................................................................................20
7.3.5 Typical Transmit Performance with CMX7364 FI-4...........................................................................................................25
7.4 Troubleshooting................................................................................................................................................................32
7.4.1 Receiver Operation............................................................................................................................................................32
7.4.2 Transmitter Operation ......................................................................................................................................................32
8Performance Specification ...............................................................................................................................................33
8.1 Electrical Performance ......................................................................................................................................................33
8.1.1 Absolute Maximum Ratings ..............................................................................................................................................33
8.1.2 Operating Limits ................................................................................................................................................................33
8.1.3 Operating Characteristics..................................................................................................................................................34

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Table Page
Table 1 Connector List...........................................................................................................................................................................9
Table 2 Test Points.................................................................................................................................................................................9
Table 3 DE9941A Channel Table..........................................................................................................................................................14
Table 4 Sensitivitylevels (mean power) for different gross (on-air) bit rates in a 25kHz channel.....................................................21
Table 5 4-QAM Rx Adjacent Channel Rejection with a FM Interferer at +/-25kHz Offset..................................................................22
Table 6 16-QAM Rx Adjacent Channel Rejection with FM Interferer at +/-25kHz offset...................................................................23
Table 7 64-QAM Rx Adjacent Channel Rejection with a FM Interferer a t +/-25kHz offset.................................................................23
Table 8 Co-channel Performance for different gross (on-air) bit rates...............................................................................................23
Table 9 Rx Intermodulation Performance for 4-QAM in Enhanced IP3 mode....................................................................................24
Table 10 4-QAM Rx Spurious Response and Blocking Performance ...................................................................................................25
Table 11 Tx Performance at 366.5MHz with different QAM and Channel Filter Types......................................................................25
Table 12 Summaryof 16-QAM Tx Output Power and ACP Performance ...........................................................................................26
Table 13 Receiver - Possible Errors......................................................................................................................................................32
Table 14 Transmitter - Possible Errors.................................................................................................................................................32
Figure Page
Figure 1 Block Diagram..........................................................................................................................................................................4
Figure 2 Typical Evaluation Connections for DE9941A..........................................................................................................................7
Figure 3 PCB Layout: top......................................................................................................................................................................10
Figure 4 PCB Layout: bottom...............................................................................................................................................................10
Figure 5 FunctionImage Load...............................................................................................................................................................13
Figure 6 Setup Script Channel No Selection .........................................................................................................................................15
Figure 7 Setup Script User Prompt to Ensure Rx Input is OFF to Allow RxDC Calibration...................................................................15
Figure 8 Setup Script User Prompt to Check Rx Performance .............................................................................................................16
Figure 9 Setup Scri pt User Prompt to Check Tx Null Condition ...........................................................................................................16
Figure 10 Setup Script Log Screen after Script has completed ............................................................................................................17
Figure 11 RxScript User Prompt to Enable AGC...................................................................................................................................18
Figure 12 Tx Script User Prompt to Select Modulation Type to Send (4, 16,32 or 64) .......................................................................18
Figure 13 Rx Script Log Screen Following Successful Reception ..........................................................................................................19
Figure 14 Tx Scri pt Log Screen Following Successful Transmission......................................................................................................19
Figure 15 Typical ber_results.txt file Output From the Rx...................................................................................................................20
Figure 16 Rx Sensitivity with 4-QAM, 16-QAMand 64-QAM at 18 ksymbols/s..................................................................................21
Figure 17 Rx Sensitivityat Different Frequencies with 4-QAM, 18 ksymbols/s..................................................................................22
Figure 18 4-QAM, 16-QAM and 64-QAM Co-Channel Performance...................................................................................................24
Figure 19 16-QAM, 18ks/s, ACP Performance at 350.05MHz............................................................................................................26
Figure 20 16-QAM, 18ks/s, ACP Performance at 366.5MHz ..............................................................................................................26
Figure 21 16-QAM, 18ks/s, ACP Performance at 399.55MHz............................................................................................................27
Figure 22 16-QAM, 9.6ks/s, ACP Performance at 366.5MHz..............................................................................................................27
Figure 23 16-QAM, 40ks/s, ACP Performance at 366.5MHz ...............................................................................................................27
Figure 24 16-QAM, 18ks/s, Constellation and EVMat 366.5MHz......................................................................................................28
Figure 25 16-QAM, 9.6ks/s, Constellation and EVMat 366.5MHz......................................................................................................28
Figure 26 16-QAM, 40ks/s, Constellation and EVMat 366.5MHz......................................................................................................28
Figure 27 Wideband Plots of Tx at 350.05MHz ...................................................................................................................................29
Figure 28 Wideband Plots of Tx at 366.5MHz .....................................................................................................................................29
Figure 29 Wideband Plots of Tx at 399.55MHz ...................................................................................................................................29
Figure 30 Ramp-up and Ramp-down Profile (QAM)............................................................................................................................30
Figure 31 Tx Spectral Puri tyin Transient Mode, 200kHz Span (QAM)................................................................................................30
Figure 32 TxSpectral Purityin Transient Mode, 1MHz Span (QAM)...................................................................................................30
Figure 33 TxSpectral Purityin Transient Mode, 10MHz Span (QAM) .................................................................................................31
It is always recommendedthat you checkfor the latest product datasheet version from the Products page of the CML website:
[www.cmlmicro.com].
History
Version
Changes
Date
1
First Issue
April 2020

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2Block Diagram
Frac-N
PLL
CMX994E I
Q
I
Q
Ref Osc
(38.4MHz)
Tx/
Rx
PA
(RF5110G)
Regulator
J5
Power +V
Regulator
Regulator
Regulator
+3V3D
+3V3A
+3V3A_RX
+3V3_VCO
J7
Antenna
Internal
VCO
2
2
2
2
MAIN
ADCs
MAIN
DACs
AUXADC/
DAC
RAMDAC
GPIO
THRU
C-BUS
C-BUS
USB
Interface
CMX998
5
4
4
4
Rx_EN
Tx/Rx
External LO
KEY
Interface Connector
Coax Connector
CMX7364
Regulator +3V3A_TX
/2
STM32
ARM
19.2MHz
USB
Figure 1 Block Diagram

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3PreliminaryInformation
The DE9941A provides a RFplatform for demonstration and evaluation of the CMX7364 Multi-mode High Performance
Wireless Data Modem, with the use ofthe CMX994E Direct Conversion Receiver and the CMX998 Cartesian Feedback
Loop Transmitter. A 1W power amplifier has been included plus Fractional-N PLL with integral VCO for stand-alone
operation.
The DE9941A is designedto be used with the ES9941A software package running on a PC which provides controller
functionality via the USB interface. Thissoftware allows scripts to be used to control the CMX7364. All RF circuits are
controlled via the CMX7364 C-BUS interface. Various scripts are available for use with the DE9941A (see section 7.3.1).
Alternatively users may implement their own host controller solution on the ARM (STM32) microcontroller.
3.1 Laboratory Equipment
The following laboratory equipment is needed to use this demonstration/evaluation kit:
Power Supply
Spectrum Analyser
RF Signal Generator
Oscilloscope
Personal Computer + USB interface
For more detailed design or investigation work, additional RF test equipment may be required.
3.1.1 Power Supply
The supply input voltage to the PCB is nominally 4.5V (3.6V to 4.8V acceptable). On-board regulators are provided to
generate all voltage rails used on the PCB (3.3V). The 4.5V supply should be rated at 2A.
NOTE: Care should be exercised with the suppliesas they are not protectedfor reverse polarity. The 4.5V supply directly
feeds the power amplifier and it should not exceed 5.0V for nominal operating limits.
3.2 Handling Precautions
Like most evaluation kits, this product is designed for use inoffice and laboratoryenvironments. The following practices
will help ensure its proper operation.
3.2.1 SSD Devices
This product uses low-power CMOS circuits that can be damaged by electrostatic discharge. Partially-
damaged circuits can function erroneously, leading to misleading results. Observe ESD precautions at all
times when handling this product.
3.2.2 Contents - Unpacking
Please ensure that you have received all ofthe items on the separate information sheet (EK9941A-375) and notify CML
within seven working days if the delivery is incomplete.
3.3 Approvals
This product is not approved to any EMC or other regulatory standard. Users are advised to observe local statutory
requirements, which may apply to this product and the radio frequency signals that may emanate from it.

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4Quick Start
This sectionprovides instructions for users who wish to experiment immediately with this Evaluation Kit at 350 to
400 MHz. A more complete description of the kit and its uses appears later in this document. The user should read the
appropriate CMX7364, CMX994E and CMX998 Datasheets before using the DE9941A board.
This Quick Start configurationassumes that the user has installed the ES9941A Windows GUI software which provides the
interface between DE9941A anda controlling PC. The script language used is the same as the PE0003. The PE0003 Script
Language Reference documentis available from the Design Resources area of the PE0003 product page on the CML
website.
4.1 Setting-Up
The following procedure is recommended:
1. Connect the boards as shown in Figure 2. J7should be connected to either an RF signal generator or spectrum
analyser via a suitable 50Ω attenuator. If testing the transmitter, the RF output J7shouldbe connectedto a suitable
50load.
THE USE OF AN EXTERNAL 50Ω LOAD IS ESSENTIAL TO PREVENT POSSIBLE DAMAGE TO THE RF POWER AMPLIFIER
STAGE.
2. Connect the PC to the DE9941A USB interface connector J4, note that this will apply power to board via the USB
interface.
3. Apply power to the DE9941A, note that connecting the USB interface willapply power sufficient forRx operation but
not Tx operation. For Tx operation a power supply capable of 2A i s required.
4. Installthe ES9941A software when prompted.
5. The CMX7364 fitted to the DE9941A must be loadedwith the requiredFunction ImageTM. This can be done using the
GUI. Programmingof the RF PLL IC,the CMX994E and the CMX998 is via the GUI using a suitable script, for which
examples are available (see section 7.3.1).
The board is now ready for operation.

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CMX7364
DE9941A
USB
Connection
to PC
J4
J5
-
J7
RF Signal
Generator
RF Spectrum
Analyser
CMX998
+4.5V
GND
CMX994E
30dB RF
Atten
Modulation
Source
ARM
Figure 2 Typical Evaluation Connections for DE9941A
4.1.1 ES9941A Software and Driver Installation
When connecting the DE9941A for the first time the Windows 10 driver for the STM microcontroller should be
automaticallyinstalled.If any problems are experiencedthe STM32 Virtual Com Port drivercan be downloaded from the
STM website. The GUI is available to download from the CML website. The script language is described in the PE0003
User Manual.

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4.2 Configuration
The CMX7364 must be loaded with a Function Image (FI) to initialise the device and determine the modulation type; FI -
1.x s upports GMSK/GFSK, FI -2.x supports multi-level FSK and FI-4.x supports 4/16/64-QAM. This User Manual focuses on
FI-4.x because this fully utilities the Tx functionality due to QAM being a non-constant envelope modulation.
The following procedures allow the user to quickly set up the DE9941A for Rx or Tx operation.
4.2.1 Tx Configuration
The following steps will configure the DE9941A to transmit at 361.05MHz with a continuous 4-QAM PRBS modulated
output. Set the applied signals and run the scripts (see section 7.3.1 for details on the scripts) in the order shown in the
following table. Note: Ensure J7 is connected to a Spectrum analys er via a suitable 50Ω attenuator for Tx testing.
Note: Settingthe CML device registers requires the use ofthe DE9941A host connected as above. The CML datasheets
give details of the registers and commands.
Script/Command
Setting
Note
DE9941A-QAM-
Setup
Script allows selection of:
Baud rate
Rx Bandwidth
Mod size
Frequency
At top of the script ensure: Baud rate 18 ks ymbols/s, Rx_BW
= 25, modulation = 4 and Channel No = 4 (Operating
Frequencyis 361.05MHz).
DE9941A-QAM-
setup
Script automaticallyperforms a
full DC Calibration on the
CMX998
User is promptedby script to checkcarrier null if required. If
yes is selected the carrier nullcan be analysed. Note PA will
be enabled at thispoint. The Tx output level should be
<-25dBm, the output should be nulled unmodulated carrier.
Write $103A to
modem control
register ($6B)
Apply Tx PRBS
The Tx output willnowbe at full output power (circa
+25dBm mean) continuously.
Note: due to limited heatsinkingin the compact design it is
advised to avoid leaving the Tx in this state for long periods
of time.
4.2.2 Rx Configuration
The following steps will configure the DE9941A to receive at 361.05MHz with a 1kHz tone IQ output. Set the applied
signals and run the scripts (see section 7.3.1 for details on the scripts) as shown in the following table.
Note: Ensure that J7 is connected to a RF signal generator via a suitable 50Ω attenuator for Rx testing.
Settingthe CML device registers requires the use ofthe DE9941A host connected as above. The CML datasheets give
details of the registers and commands.
Signal/Script
Setting
Note
DE9941A-QAM-setup
Script allows selection of:
Baud rate
Rx Bandwidth
Mod size
Frequency
At top of the script ensure: Baud rate 18 ksymbols/s, Rx_BW
= 25, modulation = 4 and Channel No = 4 (Operating
Frequencyis 361.05MHz).
ANTENNA (J7)
361.051MHz
The input level here may be user defined: for an input signal
of –60dBm at J7, the typical single-ended output level would
be ~410mV p-p at TL2. The output should be a 1kHz sine
and cosine wave on I and Q when the configuration in this
table is completed.
RXIP
(TL2)
RXI output
The differential I signalcanbe measured at TL2 and the
differential Q signal can be measured at TL3.
4.3 Operation
Following the configurationprocedures given insections 4.1 and 4.2 the DE9941A s hould be operating as a transmitter or
receiver at 361.05MHz. Various evaluation tests can now be performed.

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5Signal Lists
Table 1 Connector List
CONNECTOR PINOUT
Connector
Ref.
Connector
Pin No.
Signal
Name
Signal
Type
Description
J7
N/A
ANTENNA
RF
Tx Output or Rx Input
J5
2
+V
DC
4.5V Power supply input
J5
1
GNDA
DC
Power supply ground
Table 2 Test Points
TEST POINTS
Test Point
Ref.
Default
Measurement
Description
TP1
-
AUXDAC2 –VCTCXO Control Voltage
TP2
-
IRQN on ARM
TP3
-
AUXADC1 –Tx Instability Detector Output
TP4
1.6V dc
CMX998 BVRef (Buffered Vref)
TP5
-
AUXADC3 –CMX998 Q Feedback Path Output
TP6
-
AUXADC4 –CMX998 I Feedback Path Output
TP7
-
AUXADC2 –CMX998 DC Meas –used for DC Calibration
TP8
3.3V dc
+3V3D - Digital Power Supply
TP9
3.3V dc
+3V3A - Analogue Power Supply
TP10
3.3V dc
+3V3_VCO - VCO and PLL Power Supply
TP11
0V
DGND - Digital Ground
TP12
3.3V dc
+3V3A_RX - Rx Analogue Power Supply
TP13
-
+3V3A_TX - Tx Analogue Power Supply
TP14
1.3 –1.4VDC-
VCO Control Voltage
TP15
-
RXI+
TP16
-
RXI-
TP17
-
GPIOD/RXD
TP18
-
RXQ+
TP19
-
RXQ-
TP20
3.3V dc
CMX994E Vddio Power Supply Voltage
TP21
-
TXEN+V Tx/Rx PIN switch supply
TP22
-
AUXDAC1 - PARAMP PA control ramp
TP23
-
VAPC –PA control pins
TP24
-
CMX7364 –SYSCLK1
TP25
-
CMX7364 –SYSCLK2
TP26
-
VBAT –Back up voltage supply 1
Notes: I/P = Input
O/P = Output
TP = Test Point

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6Circuit Schematicsand Board Layouts
The DE9941A circuit schematic is available as separate high-resolution files, which can be downloaded from the CML
website. The layout on each side of the pcb is shown in Figure 3 and Figure 4 below.
Figure 3 PCB Layout: top
Figure 4 PCB Layout: bottom

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7DetailedDescription
The DE9941A functionality includes :
Nominal +4.5V Supply
Direct Conversion Receiver
Cartesian Feedback Loop Transmitter
1W Power Amplifier
Fractional-N PLL withintegrated VCO
38.4MHz VCTCXO
Operation from 350 to 400 MHz
USB Interface that allows the card to be connected to a host PCand allows control of all device functions, to support
initial test and customer evaluation.
Capabilityto demonstrate the performance of the CMX7364 Multi-mode High Performance Wireless Data Modem,
for example 4/16/64-QAM, 2/4FSKand GMSK.
In summary, the DE9941A allows the user to experiment and investigate all aspects of the CMX7364 device using an RF
platform based aroundthe CMX994E Direct Conversion Receiverandthe CMX998Cartesian Feedback Loop Transmitter.
The DE9941A is designedto allow user modification to support detailed investigation of the user’s various applications.
The evaluationplatform also includes additionalcircuits that allow the user to use the, DE9941A in standalone mode for
example a fractional -N PLL (U5) with integrated VCO.
7.1 Hardware Description
7.1.1 Harmonic Filter
L17, L18 and associated components forma low-losslow pass filter with taps centredat the 2nd and3rd Tx ha rmonics. This
filter is commonto the transmitter and receiverpaths and is connected between the Tx/R x switch and the antenna
connector J7.
7.1.2 Tx/Rx Switch
The Tx/Rx switch is a classic series-shunt switch using PIN diodes(D9 a nd D10) a fter a lumped quarter wave s ection. The
diodesare activated in transmit via the GPIOC/TXD signal fromthe CMX7364.An additional diode is provided (at D10), in
anti-parallel, to protect the LNA from extremely strong signals(e.g. a nearby transceiver). This branchof the switch then
goes to the receiver input.
7.1.3 Coupler
The coupler is a l umped coupler formed around one of the low passsections of the harmonic filter (L17). The signal is
coupled from this lowpass sectionto anotherlow pass section (L14) via very low value capacitors (C166 & C167). The
coupl ing factor is ~ 31dB and the output of the coupler forms part of the feedback path to the CMX998 to create the Tx
cartesian loop.
7.1.4 Power Amplifier
The DE9941A includes a 1W Power Amplifier U2 (RF5110G) configured for 350 to 400 MHz operation and is capable of
producing ~+25dBm (mean) output power with 16-QAM modulation.
The CMX7364 RAMDAC(AUXDAC1) output is connectedto the PA control line via a diode and transistor (D8 and TR9) to
provide sufficient current to the PA control pins.
7.1.5 Transmitter
The transmitter is based on the CMX998 Cartesian FeedbackLoop Transmitter (CFBL) IC plus the PA and coupler which
complete the loop. The up-converter, down-converter andLO Input are matched with broadband baluns. The LO is at two
times the final operating frequency(700 to 800 MHz). The CMX998 IQdifferential inputs are provided straight from the
CMX7364 main DAC’s. The error amplifier is configured with a loop filter optimised for operation with the on -board
power amplifier and for modulation bandwidths up to 50kHz.
The DCMEAS pin is connected to an AUXADC (2) on the CMX7364 to allowautomatic DC calibration and the ability to
control the PA from the CMX7364.
The CMX998 is controlled via the CMX7364 SPI-Thru port using chip select 1 (SSOUT1).

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7.1.6 Receiver
The receiver uses the CMX994E Direct Conversion Receiver which is capable of supporting a range ofdigital radio systems
of both constant envelope and linear modulation types. The CMX994E integrated LNA has been utilised with the output
of the LNA matched directlyto the IQ down conversion mixer. The mixerconverts the received signal to IQ baseband
format, where C129 and C130 combinewith on-chipcomponents to remove off-channel signals. The signal is then
amplified before further filteringto remove adjacent channelsignals (C127 and C128). The nominal maximum bandwidth
of the adjacent channel filters is 16kHz and this is scaled by a factor of 2 or 4 in the other filter bandwidth s tates. A final
amplifier stage completes the receiver line-up, providing di fferential IQ outputs directly to the CMX7364 Main ADCs.
The overall receivergain and noise figure forthe default configuration is ~63.5dB and ~6dB respectively. The Rx input
third-order intercept point is ~ -2 to -3dBm in normal mode and ~+1 to +2 dBm in enhanced mode .
The LO input is at two times the final operating frequency.
The CMX994E is controlled via the CMX7364 SPI-Thru port using chip select 1 (SSOUT1).
7.1.7 Local Oscillator
The LO (Local Oscillator) for the Tx and the Rx is at two times the final operating frequency. The LMX2571 has been used
to provide the LO, it integrates a Fractional N PLL, VCO, programmable dividers and output buffers . The LMX2571 also
includes a partiallyintegrated loopfilter. The LMX2571 (U5) is controlled via the CMX7364 SPI Thru port and uses chip
select 2 (SSOUT2).
If required an external LO source (J6 PCB pad) can be used instead of the on-board VCO.
7.1.8 Reference Oscillator
A 1.5ppm 38.4MHz VCTCXO (Golledge MP08120) is usedas the reference for the Frac-N PLL and is divided by 2 for the
CMX7364 (U6) and ARM (U10 - STM32).
7.1.9 Power Supply
The input to the PCB is nominally 4.5V (3.5V to 4.8V is acceptable). On-boardregulators are provided to generate voltage
rails used on the DE9941A.
7.1.10 Inductors
All inductors used in the RF sections of the design are manufactured by Coilcraft (www.coilcraft.com). Performance ofthe
circuits with inductors from other manufacturers may vary.
7.1.11 Adjustments and Controls External/Internal LO
An external LO may be applied at J6 but R96 should be moved to position R97 and the LMX2571 powered down.
7.2 Software Description
Please refer to the PE0003 User Manualfor detailed description of the script handler software (see www.cmlmicro.com
for more information). This is implementedon the on-boardARM microcontroller using the USBinterface to a suitable PC
running the ES9941A GUI. Section 7.3.1 gives detailed informationabout scripts developed for the DE9941A Evaluation
kit.
7.3 Application Information
See section 4.1 for board setup details and section 4.2 for operating the DE9941A as a transmitter or receiver.
7.3.1 GUI Description
The GUI has a number of tabs as follows :
C-BUS Control –allows single register write andread commands to the selected device (device 1 onlyshould
be used).
C-BUS Ctrl Ext 1 and 2 –a set of register writes and reads canbe configured, savedand recalled (device 1
only should be used).
Function Image Load –user can browse to the FI location and load the FI to device 1. If the “Read Three
Words” is ticked the FI version number will be displayed correctly.

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Script Handler –allows users to execute script files consisting of register write, read, and delaycommands.
Section 7.3.3 provides a description ofsome scripts providedto demonstrate the functionalityof the
DE9941A with FI-4.
7.3.2 Function Image Load
Using the Function Image Load tab the latest FI-4 firmware can be loaded. Figure 5 shows the GUI after a successful load
of the FI.
Figure 5 Function Image Load
7.3.3 Scripts Handler Tab
Scripts can be executed using the “Script Handler” tab - browse to the relevant scripts and then press Run.
The following scripts are available to support the DE9941A:
DE9941A_QAM_Setup –Must be run first on the Tx and Rx device
DE9941A_QAM_Test_RX–BER Script to be run first on the Rx
DE9941A_QAM_Test_TX–Only used with the Tx device
The scripts assume that the user hastwo DE9941As, one for Tx and one for Rx, although the setup script can be used to
check the static performance of the Rx and Tx if required. A brief description ofthe function of each script is given in the
following sections.

Advanced SDR Demonstrator DE9941A
2020 CML Microsystems Plc 14 UM9941A/1
DE9941A_QAM_Setup
At the top of this script there is a section which allows the user to adjust some variables: theseare baud rate, Rx channel
BW, modulationtype and channel No. The baud rate can be set to 9.6 k, 18 k,and 40 k.Other baud ratescan be used but
the script is optimised for use with these three baud rates. The receiver ACR bandwidthcanbe changed using the variable
Rx_BW. Va lid values are 12 for 12. 5kHz system, 25 for 25kHz system a nd 50 for 50kHz s ystem. The QAM modulation type
can be set to 4, 16 and 64. The script includes a channeltable which configures the LMX2571 over the entire operating
range of 350.05MHz to 399.55MHz. The channel table is shown in Table 3.
Table 3 DE9941A Channel Table
Frequency (MHz)
Channel No
351.25
1
353.5
2
355.95
3
361.05
4
363.5
5
365.95
6
350.05
7
366.5
8
383.5
9
399.55
10
The script configures the CMX994E and CMX998. To ensure the best receiver performance is achieved it is necessary to
train the Rx equaliser in the CMX7364; this has to be done with a good quality 4QAM input signal. The setup script has
pre-trained equaliser filter values for the following three cases; 9.6 ks/s using the mi nimum ACR filter s etti ng (12.5kHz
system), 18 ksymbols/s using the mid filter setting (25kHz system) and 40 ksymbols/s using the maximum filter setting
(50kHz system). The trainedequaliser filter will automatically be loaded depending on the Rx_BW setting. The setup
script performs a DC calibrationof the CMX994E, the user is prompted to turn anyinput signaloff while this is done so
that the best result is achieved. The script log screen will tell the user what final value has been programmed in the
extended DC offset register ($17) of the CMX994E.
The setupscriptalso sets up and executes a fullDCcalibrationof the transmitter (CMX998). It also configures the high
gain calibration condition for any subsequent DC calibrations performed on the transmitter.
The setupscript also gives the user the abilityto analyse the Rx performance typically described in section 4.2.2 and the
Tx performance as described in section 4.2.1. See screenshots of the GUI in Figure 6 to Figure 10 which show the user
prompts that occur during the execution of the setup script.

Advanced SDR Demonstrator DE9941A
2020 CML Microsystems Plc 15 UM9941A/1
Figure 6 Setup Script Channel No Selection
Figure 7 Setup Script User Prompt to Ensure Rx Input is OFF to Allow Rx DC Calibration

Advanced SDR Demonstrator DE9941A
2020 CML Microsystems Plc 16 UM9941A/1
Figure 8 Setup Script User Prompt to Check Rx Performance
Figure 9 Setup Script User Prompt to Check Tx Null Condition

Advanced SDR Demonstrator DE9941A
2020 CML Microsystems Plc 17 UM9941A/1
Figure 10 Setup Script Log Screen after Script has completed
DE9941A_QAM_RX and DE9941A_QAM_TX
At the top of the scripts the user can select whether to test with raw or coded data (0 = raw/non-coded and 1 = coded)
and how many bursts to do the test over.
Basedon a back-to-back test the Rx script is run first and it will prompt the user if they want to enable AGC, see Figure 11.
The Tx script is then run and the user will be prompted to choose the desired modulation type to be sent, this can be 4,
16, 32 or 64 QAM, see Figure 12 which shows a screenshot of the Tx script prompt.
Following successful reception and transmissionthe log screens shown in Figure 13 and Figure 14 can be observed. The
results ofthe complete test are alsowrittento a text file (ber_results.txt) in the same directoryas the scripts are stored; a
screenshot ofa typical txt file output is shown in Figure 15. From this the user can see confirmation of the test s cenario
alongside the reported EVM (signalquality), frequency offset, BE (bit errors per burst), A (AGC setting; 7 = max gain to 0 =
min gain), RSSI (in dBm), IQ DC offsets and T (timer) per bursts plus the total errors.

Advanced SDR Demonstrator DE9941A
2020 CML Microsystems Plc 18 UM9941A/1
Figure 11 Rx Script User Prompt to Enable AGC
Figure 12 Tx Script User Prompt to Select Modulation Type to Send (4, 16, 32 or 64)

Advanced SDR Demonstrator DE9941A
2020 CML Microsystems Plc 19 UM9941A/1
Figure 13 Rx Script Log Screen Following Successful Reception
Figure 14 Tx Script Log Screen Following Successful Transmission

Advanced SDR Demonstrator DE9941A
2020 CML Microsystems Plc 20 UM9941A/1
Figure 15 Typical ber_results.txt file Output From the Rx
7.3.4 Typical Receiver Results with CMX7364 FI-4
The ReceiverResponse Equaliser within the CMX7364 has been used insingle mode to create a channel filter that has
compensationfor the ADCs and also the channel filtering withinthe Rx chain. The AAF (Anti-Alias filter inthe CMX7364) is
at its default setting of50kHz, 3dB bandwidth. The ACR (Adjacent ChannelRejection) filters on the CMX994E are in the
intermediate bandwidth state (typically 8kHz -3dB bandwidth).
In all of the following results the data rate is 18 ksymbols/s and, in the following table, the raw over-air bit rate for the
three different modulation types have been highlighted. Also, the RRC channel filter usedin all cases hasan alpha of 0.2.
Parametric measurements and graphs shown are typical only, not guaranteed performance limits.
QAM Modulation
Type
Bits per Symbol
Base Over-air Bit Rate
(18 ksymbols/s)
Raw Mode Over-air Bit Rate
(18 ksymbols/s)
4-QAM
2
36,000 bps
32,000 bps
16-QAM
4
72,000 bps
64,000 bps
64-QAM
6
108,000 bps
96,000 bps
The difference between the base over-air rate and the raw mode rate (whichis the actual user data rate in raw mode at
18 ksymbols/second) is due to some symbolsbeingused internally bythe modemto perform channel equalisation. All
measurements reference ETSI EN 300 113 (v2.2.1 –Dec 2016) specification.
All of the detailed receiver performance results were taken with a CML PE0602-7364 and an IQ Vector Signal Generator as
the wanted signal.