MOGlabs ARF021 User manual

Agile RF Synthesizer & AOM driver
ARF021/ARF421, XRF021/XRF421
Version1.3.0,Rev2,3and4.

Limitation of Liability
MOGLaboratoriesPtyLtd(MOGLabs)doesnotassumeanyliabil-
ity arising out of the use of the information contained within this
manual. This document may contain or reference information and
products protected by copyrights or patents and does not convey
any license under the patent rights of MOGLabs, nor the rights of
others. MOGLabs will not be liable for any defect in hardware or
softwareorlossorinadequacyofdataofanykind,orforanydirect,
indirect, incidental, or consequential damages in connections with
orarisingoutoftheperformanceoruseofanyofitsproducts. The
foregoing limitation of liability shall be equally applicable to any
serviceprovidedbyMOGLabs.
Copyright
Copyright c MOG Laboratories Pty Ltd (MOGLabs) 2015–2017.
Nopartofthispublicationmaybereproduced,storedinaretrieval
system, or transmitted, in any form or by any means, electronic,
mechanical, photocopying or otherwise, without the prior written
permissionofMOGLabs.
Contact
Forfurtherinformation,pleasecontact:
MOGLaboratoriesP/L
Suites34–35
49UniversitySt
CarltonVIC3053
AUSTRALIA
[phone]
[email protected]
www.moglabs.com
MOGLabsUSALLC
41914thSt
HuntingdonPA16652
USA
[phone]
[email protected]
www.moglabsusa.com
MOGLabsEurope
Goethepark9
10627Berlin
Germany
[phone]
info@@moglabs.eu

Preface
Acousto-opticmodulators(AOMs)areanintegralpartofmanylaser-
basedexperiments. Theyareusedforfrequencyshifting,amplitude
modulation,andlaserfrequencystabilisation. Manyexperimentsre-
quireverysimplecontroloftheRF frequencyandpower,butothers
require sophisticated sequences. The MOGLabs ARF/XRF agile RF
synthesizerprovidessuchcomplexitywithauser-friendlyinterface.
The extraordinary capabilities of the ARF/XRF have not previously
been available from any single supplier, let alone in a single unit.
Two channels, with direct output of up to 4W per channel. Wide
frequency range of 20 to 400MHz. Arbitrary frequency, amplitude
andphasewithhighresolution. Analoguemodulationofeachchan-
nel,infrequency,amplitude,and/orphase,with10MHzbandwidth.
Ergonomicfront-panelcontrols, andethernet/USB interface. Table-
modeoperationtodefinecomplextime-dependentwaveformoutput.
All in one box which connects directly to AC mains power and to
yourAOMs. Asyoudelveintothismanualyouwilluncovermoreand
morecapability,butthepowerfulFPGA attheheartoftheARF/XRF
allowssoftwareimprovementstoaddnewfeatures,sopleasecheck
theMOGLabswebsiteforupdates,examplecode,andassistance.
WehopethatyouenjoyusingtheARF/XRF,andpleaseletusknow
if you have any suggestions for improvement in the ARF/XRF or in
thisdocument,sothatwecanmakelifeinthelabbetterforall.
MOGLabs,Melbourne,Australia
www.moglabs.com
i

ii

Safety Precautions
Safeandeffectiveuseofthisproductisveryimportant. Pleaseread
thefollowing safetyinformationbeforeattemptingtooperate. Also
please note several specific and unusual cautionary notes before
using the MOGLabs ARF/XRF, in addition to the safety precautions
thatarestandardforanyelectronicequipment.
CAUTION Toensurecorrectcoolingairflow,theunitshouldnotbeoper-
atedwithcoverremoved.
WARNING Highvoltagesareexposedinternally,particularlyaroundthe
mains power inlet and internal power supply unit. The unit
shouldnotbeoperatedwithcoverremoved.
NOTE The MOGLabs ARF/XRF is designed for use in scientific re-
search laboratories. It should not be used for consumer or
medicalapplications.
iii

Protection Features
TheMOGLabsARF/XRF includesanumberoffeaturestoprotectyou
andyourdevice.
Open/short circuit EachRF outputshouldbe connectedtoa50Ωload. TheAR-
F/XRFwilldisableeachhigh-powerRFoutputifnotconnected
orifashort-circuitisdetected.
Reflected power The RF reflected power and VSWR (voltage standing wave
ratio)aremonitoredandRFoutputisdisabledifeitherexceeds
theirsafelimitsettings.
Mains filter Protectionagainstmainstransients.
Temperature Severaltemperaturesensorscontrolthefanandwilltriggera
shutdownifthetemperatureexceedsasafelimit.
iv

Contents
Preface i
Safety Precautions iii
Protection Features iv
1 Introduction 1
1.1 Operatingmodes..................... 2
1.2 RF on/offcontrol ..................... 4
2 Connections and controls 5
2.1 Frontpanelcontrols . . . . . . . . . . . . . . . . . . . 5
2.2 Frontpaneldisplay/monitor. . . . . . . . . . . . . . . 6
2.3 Rearpanelcontrolsandconnections. . . . . . . . . . 7
2.4 InternalDIPswitches . . . . . . . . . . . . . . . . . . 8
3 Communications 11
3.1 Protocol.......................... 11
3.2 TCP/IP........................... 13
3.3 USB............................ 14
4 MOGRF host software 17
4.1 Devicediscovery . . . . . . . . . . . . . . . . . . . . . 17
4.2 Devicecommander . . . . . . . . . . . . . . . . . . . . 18
4.3 MOGRFmainwindow . . . . . . . . . . . . . . . . . . 19
4.4 Tableviewer........................ 23
4.5 ExternalI/Osettings . . . . . . . . . . . . . . . . . . . 24
5 External modulation 27
5.1 Operationalprinciple. . . . . . . . . . . . . . . . . . . 27
5.2 Modulationgain . . . . . . . . . . . . . . . . . . . . . 28
v

vi Contents
5.3 Dualmodulation: fastandslowmodes . . . . . . . . 29
5.4 Examples.......................... 30
6 PID stabilisation 35
6.1 Signalconditioning. . . . . . . . . . . . . . . . . . . . 35
6.2 PIDcontrolloop . . . . . . . . . . . . . . . . . . . . . 36
6.3 DualmodulationwithPID . . . . . . . . . . . . . . . 37
6.4 Noise-eaterimplementation. . . . . . . . . . . . . . . 38
6.5 Example.......................... 39
7 Digital I/O 41
7.1 DB15connector...................... 41
7.2 High-speeddigital . . . . . . . . . . . . . . . . . . . . 43
7.3 Configuration....................... 44
7.4 TTLswitching....................... 46
7.5 Externalswitchingtiming . . . . . . . . . . . . . . . . 48
7.6 Counters.......................... 50
7.7 Examples.......................... 51
8 Simple table mode 53
8.1 Operationalprinciple. . . . . . . . . . . . . . . . . . . 53
8.2 Definingtableentries . . . . . . . . . . . . . . . . . . 54
8.3 DigitalI/O......................... 57
8.4 Loopsandtriggers . . . . . . . . . . . . . . . . . . . . 62
8.5 Uploadanddownload . . . . . . . . . . . . . . . . . . 65
8.6 Re-armandrestart . . . . . . . . . . . . . . . . . . . . 66
8.7 Linearramps ....................... 67
8.8 Synchronoustableexecution . . . . . . . . . . . . . . 69
9 Advanced table mode (XRF) 71
9.1 Operationalprinciple. . . . . . . . . . . . . . . . . . . 71
9.2 Definingtableentries . . . . . . . . . . . . . . . . . . 72
9.3 Initialandfinalstates . . . . . . . . . . . . . . . . . . 76
9.4 Counters.......................... 77
9.5 Loopsandtriggers . . . . . . . . . . . . . . . . . . . . 78
9.6 Linearrampsusingextrapolation. . . . . . . . . . . . 79
9.7 Frequencygain...................... 81
9.8 Otherinstructionparameters . . . . . . . . . . . . . . 83

Contents vii
9.9 Additionalexamples . . . . . . . . . . . . . . . . . . . 84
A Specifications 89
B Firmware upgrades 91
B.1 Firmwarecomponents . . . . . . . . . . . . . . . . . . 91
B.2 Factoryreset....................... 92
B.3 Upgradeviamogrffw .................. 92
B.4 Upgradeviawebinterface. . . . . . . . . . . . . . . . 94
B.5 UpgradinganARF toanXRF .............. 96
C Command language 97
C.1 Arguments......................... 97
C.2 Generalfunctions . . . . . . . . . . . . . . . . . . . . . 98
C.3 Basiccontrol ....................... 98
C.4 PrimaryRF control.................... 99
C.5 Modulation ........................101
C.6 Digitalrampgenerator. . . . . . . . . . . . . . . . . . 102
C.7 Monitoroutputs. . . . . . . . . . . . . . . . . . . . . . 104
C.8 Clockreference . . . . . . . . . . . . . . . . . . . . . . 104
C.9 Tablemode ........................106
C.10PIDfeedback.......................108
C.11 ExternalIOfunctions. . . . . . . . . . . . . . . . . . . 110
C.12 Configurationsettings . . . . . . . . . . . . . . . . . . 112
C.13 DirectDDScontrol. . . . . . . . . . . . . . . . . . . . 112
D Code examples 115
D.1 python ...........................115
D.2 matlab ...........................117
D.3 LabVIEW ..........................118

viii Contents

1. Introduction
The MOGLabs ARF/XRF consists of two independent AD9910 direct
digital synthesizer (DDS) sources, each with 4W amplifier. The
frequency,amplitudeandphaseofeachoutputissoftware-controlled
viaamicrocontrollerandFPGA(fieldprogrammablegatearray). This
enablesdirectcontrolofthefrequency,amplitudeandphaseofthe
RFsignals,whichcanbeadjustedinreal-timeusingthefront-panel
controlknobs,orviaascriptinglanguageoverethernetorUSB.The
RFparameterscanbedefinedinalookuptable(loadedviaethernet
orUSB)toenablecomplexsequenceswithveryfasttransitions.
The block diagram below shows the key components. The RF sig-
nal output from each DDS is low-pass filtered, pre-amplified, and
FPGA
Front Panel Display & Control
Local
Oscillator
Micro
controller
DDS + RF
AD9910 DDS
LP lter
RF switch
RF amplier
Power detector
DAC
Output
A/D
(2 per channel)
RF on/o
7-pole lters
10MHz
External
Clock
Ethernet
10/100
Fast RAM
table memory
USB
RF OUT
4x MOD IN
RF on/o
RAM table
memory
1

2Chapter 1. Introduction
thenfurther amplified withaGaN hybrid high-poweroutputstage
(ARF421/XRF421 only). TheRF signalsaremonitoredtocheckoutput
powerandtomeasurethereflection(VSWR).
TheDDSchipsarecontrolledbytheFPGA.Amicrocontrollerprovides
externalinterfacewithTCPIP andUSB communications,andcontrols
thefront-paneldisplay,rotaryencoders(knobs)andpush-buttons.
The device allows analogue modulation through two analogue-to-
digitalconverters(ADC)withanti-aliasingfilters. Whenmodulation
isenabled,theFPGA periodicallyreadsthevalueofthemodulation
signaland uses that value to reprogramthe DDS frequency, power
and/orphase.
The ARF/XRF includes memory for storing complex waveform se-
quences, where each step in the sequence can include frequency,
power, phase, time delay, and more complex definitions of ramps
and other time-dependent functions. Complex capabilities can be
accessed via either TCPIP or USB communications. See Chapter 3
forinformationoncommunicationsoptionsandsetup.
Oncecommunicationsareestablished,theARF/XRFcanbecontrolled
with simple text commands. The commands can be very basic, for
exampletodefinethefrequencyorpower,ortheycandefinecomplex
dynamicsequences. AppendixCprovidesasummaryoftheavailable
commands.
1.1 Operating modes
TheARF/XRF can be used at varying levels ofcomplexity,aseither
a free-running RF source or to follow pre-determined instructions
definedinatable. Themodesofoperationareoutlinedbelow,and
thecurrentoperationalmodeofeachchannelcanbeindividuallyset
usingtheMODE command.

1.1 Operating modes 3
NSB: Basic mode
Default state on power-up. In this mode, each channel acts as a
simple single-frequency RF source, with the DDS chips controlled
directly by the FPGA. The frequency and power of the signal can
becontrolledviathefrontpanel,usingsimpleinstructionsoverthe
computer interface (e.g. FREQ or POW), or using the modulation in-
puts. Basic mode is convenient for driving AOMs and other single-
frequencydevices,withtheflexibilityofmodulationandPIDcontrol.
NSA: Advanced mode
Advancedmodeprovidesdirectuser-controlofeachDDSthroughits
internalregistersviatheDDS command. Directprogrammingofeach
DDS iscomplexandnotnecessaryformostapplications;itrequires
carefulreferencetotheAD9910 datasheetandmanualcalculationof
thehardwareregisters.
TSB: Simple table mode
In table mode, the RF parameters are automatically sequenced by
the FPGA according to a table of values pre-loaded by the micro-
controllerandsteppedthroughautomatically. Thetableentriesare
definedbysimpletextcommandsfromthehostcomputerwhichde-
fine the RF frequency, amplitude, phase and any I/O behaviour, as
detailedinchapter8. TheminimumdurationofaTSB entryis1µs
andeachtablecancompriseupto8191instructions.
TPA: Advanced table mode
XRF models provide a more advanced table mode with greatly im-
provedtimingresolutionandsingleparameterupdatesat16nsin-
tervals. Smooth pulses can be generated with precise control of
theenvelopethroughpiecewise-linearinterpolation. Detailsonad-
vancedtablemodefunctionalityaredescribedinchapter9.

4Chapter 1. Introduction
1.2 RF on/off control
TheRF outputcan be turned on andoff via software control ofthe
DDS generators (through the POW command), but for many applica-
tions that is too slow, and the extinction ratio is inadequate. The
ARF/XRFhasadditionalhardware-basedon/offcontrolontheoutput
ofeachDDS,usinganRF switchbeforetheamplifiers.
Thishardwareswitchshort-circuitstheRFoutputoftheDDS,andcan
becontrolledviaacombinationofsoftwareandhardwareinputs(see
§7.5). In this way, the RF can be controlled using the front panel,
theON/OFF commands,aswellasviatableentrieswithappropriate
flags.
ThereisadditionalcontroloftheDC suppliestothehigh-powerRF
amplifierstofurtherimprovetheextinctionratio. Theresponsetime
issignificantlylongerthanjustswitchingtheRFsignal,butreduces
theRF noiseontheoutput.

2. Connections and controls
2.1 Front panel controls
CHANNEL 1
FREQUENCY POWERFREQUENCY POWER
STATUS
STATUS
CHAN 1
CHAN 2
STATUS
CHANNEL 2
OFF
ON
OFF
ON
Agile RF Synthesizer
POWER
Frequency Thefrequencyencodercanbeusedtoadjustthefrequencyforeach
RF channel,whenoperatinginNSA mode. Thecurrentfrequencyis
displayedontheLCD display.
Power Similarly,theoutputpowercanbeadjustedforeachchannel.
OFF/ON TheRF outputcan be enabled or suppressedwiththe push-button
off/onswitchforeachchannel.
STATUS Eachchannelhasamulti-colourstatusLED indicatorwhosecolour
indicatesthecurrentoutput stateofthechannelasfollows.
Colour DDS signal Amplifiers
Off Off Off
Green On On
Yellow On Off
Blue Off On
Red Errorstate
5

6Chapter 2. Connections and controls
2.2 Front panel display/monitor
The LCD display shows key information including frequency and
powerforeachchannel,andethernetinformation.
STATUS Indicatordisplayingthestatusofthemicrocontroller.
•Blinkinggreen: Normaloperation,nofaults
•Green/blue: Normaloperation,deviceisinitialising
•Blue: Microcontrollerunresponsive,unknownstate
•Red/orange: Criticalfault,diagnosisavailable
•Red: Criticalfault,commsunavailable
Intheevent ofanunresponsiveunit,forexamplefollowingafailed
firmwareupdate,pleasecontactMOGLabsforassistance.
CHAN 1, CHAN 2 Indicatordisplayingthecurrentmode ofthechannel.
•Off: Channeldisabled/FPGAinactive
•Red: Criticalerror,channeldisabled(e.g. outputdisconnected)
•Green: NSB mode,normaloperation(front-panelenabled)
•Lightblue: NSA mode,directcontrolofDDS(nofront-panel)
•Blue: TSB mode,simpletablemode(limitedfront-panel)
•Blinking: Non-criticalerror(e.g. PIDsaturationlimit)
POWER Indicatordisplayingthestatusofthepowersupply
•Off: Nopowertounit
•Green: Unitisstartingup
•Lightblue: Normaloperation
•Orange: Supplyvoltagesoutsideexpectedrange
•Red: Criticalerrorwithsupply
Push-buttons Therearefourpush-buttons ontherighthandsideofthe LCDdis-
play,whicharepresentlyof limited functionality. Pressingthe ↑/↓
keyscyclesthroughtheoperationalmodesofCH1/CH2respectively.

2.3 Rear panel controls and connections 7
2.3 Rear panel controls and connections
RF OUT
FREQ 1 FREQ 2 CLK INRF OUT 1 RF OUT 2
AMP 1 AMP 2 MOD OUTMON 1 MON 2
MOD IN
SN:
90–264Vac 47–63Hz
WARNING: TheSMA connectorsontheback-panelaresurface-mountedtothePCB
inside the unit. Do not apply excessive force during tightening as this will break
the connector off the PCB.Finger-tightening is sufficient for the frequency range of
the ARF/XRF anduseofawrenchorspannerisstronglydiscouraged. Themaximum
recommendedtorqueis0.6Nm.
IEC power in/out TheARF iscompatiblewithallstandardAC powersystems,from90
to264Vand47to63Hz. Themaximumcurrentisabout1A.
Fan TheARFhasthreetemperature-controlledfansdirectingairflowover
theRF poweramplifiersandtheFPGA,exhaustingthroughtherear
vent. Ensurethattheventdoesnotbecomeblocked.
RF OUT TherearetwoprimaryRFoutputsandtwosecondaryRF outputsfor
monitoring. Thehigh-poweroutputsarelabelledRFOUT1andRF
OUT2,andshouldbe50Ωterminated.
MON Separatelybuffered RF outputs for monitoring, at −20dBc toeach
mainoutputwhenhigh-impedanceterminated.
MOD IN Each RF channel has two associated analogue inputs, FREQ and
AMP, nominally for frequency and amplitude modulation. The AMP
inputcanbereconfiguredtoperformphasemodulationusingtheMDN
command. Thesemodulationinputscanbeusedforlasernoise-eater
orfrequencystabilisationapplications(seechapter5).

8Chapter 2. Connections and controls
CLK IN The ARF uses a high stability OCX crystal clock, but can also be
synchronisedtoahigh-performanceexternalclock(5MHzto1GHz)
input via this connector. The input is 50Ω terminated. The signal
shouldbe1Vp-p,andpreferablysquare-wave.
MOD OUT The ARF/XRF provides three analogue outputs, ±2.5V, with 14-bit
resolution and 1MHz bandwidth, for monitoring purposes. One is
available at the MOD OUT SMA connector; the other two can be
accessedfromtheDB15 connector.
DB15 TheDB15 connectorprovidesbasicI/Ofunctionality. ThereareTTL
inputsforquicklysuppressingtheRFoutput,andTTLoutputsforcon-
trollingexperimentaldevicessuchasshutters. Twogeneral-purpose
analogueoutputs,similartoMODOUT,arealsoavailable. Thecon-
nector pinout is described in §7.1. The B3110 breakout board is
availabletoprovideconvenientSMA connectorsforthedifferentI/O
channels.
RJ45/USB-A Ethernet(TCP/IP10/100Mb/s)andUSB communicationsjacks.
2.4 Internal DIP switches
Four DIP switches are provided toassistindiagnosisand recovery
oftheARF/XRF units.
WARNING ThereispotentialforexposuretohighvoltagesinsidetheARF/XRF.
Takecarearoundthepowersupplyandensurethatobjects,partic-
ularlyelectricallyconductingobjects,donotentertheunit.
CAUTION Thecovershouldbeleftontoensureproperairflowandcooling.
OFF ON
1Normaloperation Legacyfirmwareupdatemode
2DisableFPGA Normaloperation
3Usefactorysettings Normaloperation
4Normaloperation Factoryreset

2.4 Internal DIP switches 9
DIP 1 Default OFF. If switched ON, the unit will start in legacy firmware
uploadmode. Connecttothedeviceusingaweb-browserandupload
firmware to the microcontroller. It is strongly recommended to use
mogrffw to update the firmware as described in Appendix B; this
optionisonlyprovidedasafallbackoptionincasemogrffw fails.
DIP 2 DefaultON.NormaloperationrequiresthatanFPGAimagebeloaded
fromFLASHmemoryintotheFPGA,whichtakes10–20s. Intheevent
ofacorruptFPGAimage,disableDIP2andapplyafirmwareupdate.
DIP 3 DefaultON.Devicesettings, including network settings, arestored
in EEPROM and loaded on startup. If invalid settings are saved to
EEPROM,disableDIP 3toloadfactorydefaultstofacilitatedebug-
ginganddiagnostics.
DIP 4 Default OFF. Switch ON and reboot to restore the unit to factory
settings. Firmware for both microcontroller and FPGA, as well as
theEEPROM settings,willberestored.

10 Chapter 2. Connections and controls