MOGlabs ARF021 User manual

Agile RF Synthesizer & AOM driver
ARF021/ARF421, XRF021/XRF421
Version1.7.4,Rev8hardware

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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.
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Forfurtherinformation,pleasecontact:
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AUSTRALIA
[phone]
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[phone]
www.moglabs.com

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
thefollowingsafetyinformationbefore attemptingtooperate. 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/XRFincludesanumberoffeaturestoprotectyou
andyourdevice.
Open/short circuit EachRF outputshould beconnectedtoa50Ωload. TheAR-
F/XRFwilldisableeachhigh-powerRF outputifnotconnected
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 Featurecompatibility . . . . . . . . . . . . . . . . . . 4
1.3 RF on/offcontrol ..................... 4
2 Connections and controls 5
2.1 Frontpanelcontrols . . . . . . . . . . . . . . . . . . . 5
2.2 Rearpanelcontrolsandconnections. . . . . . . . . . 8
2.3 InternalDIPswitches . . . . . . . . . . . . . . . . . . 9
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........................ 24
4.5 ExternalI/Osettings . . . . . . . . . . . . . . . . . . . 25
5 External modulation 27
5.1 Operationalprinciple. . . . . . . . . . . . . . . . . . . 27
5.2 Modulationgain . . . . . . . . . . . . . . . . . . . . . 28
v

vi Contents
5.3 Dualmodulation: fastandslowmodes . . . . . . . . 30
5.4 Examples.......................... 31
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 DE15connector...................... 41
7.2 High-speeddigital . . . . . . . . . . . . . . . . . . . . 43
7.3 XSMAbreakoutboard . . . . . . . . . . . . . . . . . . 45
7.4 Configuration....................... 46
7.5 TTLswitching....................... 48
7.6 Pulsegeneration . . . . . . . . . . . . . . . . . . . . . 49
7.7 Counters.......................... 51
7.8 Examples.......................... 52
8 Simple table mode 55
8.1 Operationalprinciple. . . . . . . . . . . . . . . . . . . 55
8.2 Definingtableentries . . . . . . . . . . . . . . . . . . 56
8.3 DigitalI/O......................... 59
8.4 Loopsandtriggers . . . . . . . . . . . . . . . . . . . . 63
8.5 Uploadanddownload . . . . . . . . . . . . . . . . . . 67
8.6 Re-armandrestart . . . . . . . . . . . . . . . . . . . . 68
8.7 Linearramps ....................... 69
8.8 Synchronoustableexecution . . . . . . . . . . . . . . 71
9 Advanced table mode (XRF) 73
9.1 Operationalprinciple. . . . . . . . . . . . . . . . . . . 73
9.2 Definingtableentries . . . . . . . . . . . . . . . . . . 74
9.3 Initialandfinalstates . . . . . . . . . . . . . . . . . . 78
9.4 Counters.......................... 79
9.5 Loopsandtriggers . . . . . . . . . . . . . . . . . . . . 80
9.6 Linearrampsusingextrapolation. . . . . . . . . . . . 81
9.7 Frequencygain...................... 83

Contents vii
9.8 Otherinstructionparameters . . . . . . . . . . . . . . 85
9.9 Additionalexamples . . . . . . . . . . . . . . . . . . . 86
A Specifications 91
B Firmware upgrades 93
B.1 Firmwarecomponents . . . . . . . . . . . . . . . . . . 93
B.2 Factoryreset....................... 94
B.3 Upgradeviamogrffw .................. 94
B.4 Upgradeviawebinterface. . . . . . . . . . . . . . . . 97
B.5 UpgradinganARF toanXRF .............. 98
C Command language 99
C.1 Arguments......................... 99
C.2 Generalfunctions . . . . . . . . . . . . . . . . . . . . . 100
C.3 Basiccontrol ....................... 100
C.4 PrimaryRF control....................101
C.5 Modulation ........................103
C.6 Digitalrampgenerator. . . . . . . . . . . . . . . . . . 105
C.7 Monitoroutputs. . . . . . . . . . . . . . . . . . . . . . 106
C.8 Clockreference . . . . . . . . . . . . . . . . . . . . . . 107
C.9 Tablemode ........................109
C.10PIDfeedback.......................112
C.11 ExternalIOfunctions. . . . . . . . . . . . . . . . . . . 114
C.12 Configurationsettings . . . . . . . . . . . . . . . . . . 116
C.13 DirectDDScontrol. . . . . . . . . . . . . . . . . . . . 117
D Code examples 119
D.1 python ...........................119
D.2 matlab ...........................121
D.3 LabVIEW ..........................122

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 with a GaN hybrid high-power outputstage
(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 valueto reprogram the 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 canbeusedatvaryinglevelsof complexity, as either
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 Feature compatibility
TheARF/XRF providesawiderangeoffunctionality,butnotallfea-
tures are compatible with each other. The following table sum-
mariseswhichfeaturescanbeusedinwhichmodes.
NSB NSA TSB TPA
Front-panelcontrols 3 7 7 7
Externalmodulation(AM/FM/PM)3 7 7 7
PID control 3 7 7 7
DirectTTL on/offcontrol 3 3 7 7
DirectDDS control 7 3 7 7
Autonomousexecution 7 7 3 3
ExternalTTL trigger 7 7 3 3
TTL output 3 3 3 3
Table 1.1: Summaryoffeaturecompatibility
1.3 RF on/off control
The RF output can be turned on and off via software control of
the DDS generators, but for many applications that is too slow
andtheextinctionratioisinadequate. TheARF/XRF hasadditional
hardware-basedon/offcontrolontheoutputofeach DDS,usingan
RF switchbeforetheamplifiers.
This hardware switch short-circuits the RF output of the DDS, and
canbecontrolledviaacombinationofsoftwareandhardwareinputs
(see §7.6). In this way, the RF can be controlled using the front
panel,theON/OFF commands,aswellasviatableentries.
ThereisadditionalcontroloftheDC suppliestothehigh-powerRF
amplifierstofurtherimprovetheextinctionratio. Theresponsetime
issignificantlylongerthanjustswitchingtheRFsignal,butreduces
theRF noiseontheoutput.

2. Connections and controls
2.1 Front panel controls
ON/OFF
CHANNEL 1 CHANNEL 2
Agile RF Synthesizer ADJUST
Figure 2.1: Front-panellayoutof Rev8 ARF/XRF devices. Otherrevisions
mayhaveadifferentappearance.
Starting with Rev6devices, the front-panel includes an interactive
menu system for controlling the device. The buttons on the right-
handsideofthedisplaynavigatethroughthemenustructure,while
theencoderwheelisusedtoeditvalues. The∧and∨keyschange
betweenmenuitems, exits to thepreviousmenu, andOK enters
theselectedmenuoractivatestheselectedcommand.
The main menu (Figure 2.2) shows the current mode and status of
eachchannel. Inbasic(NSB)mode,thecurrentfrequencyandpower
ofeachchannelisdisplayed,aswellaswhethermodulationiscur-
rentlyenabled. PressingtheOKbuttonwithachannelselectedwill
openthesub-menutoadjustsettingsforthatchannel(Figure2.3).
Thecolorofeachmenuitemrepresentsitspurpose,aslistedbelow.
White Staticvalue,displayedfordiagnosticpurposes.
Yellow Adjustablevalue,modifiedusingtheencoderwheel.
Orange Currentlyselectedchannel.
Blue Submenu,enteredwiththeOK button.
Green Command,executedbytheOK button.
5

6Chapter 2. Connections and controls
Figure 2.2: Themainmenushowsthecurrentstateofeachchannel. Left:
both channels are in basic mode, with AM and FM enabled on CH1, and
PM enabledonCH2. Right: CH2 isin basic tablemode, withthenumber
ofentriesinthetableshown.
Figure 2.3: Thebasicparametersofeachchannelcanbeediteddirectly.
Turningtheencoderwheelmodifiestheselecteddigitofthecurrentvalue
(left) as indicated by the arrow. Pressing the encoder wheel changes to
digit select mode (right), allowing the selected digit to be changed by
turningtheencoder.
Figure 2.4: The options menu allows configuration of various settings,
suchasthemaximumoutputpower(left)andethernetoptions(right).

2.1 Front panel controls 7
When an editable (yellow) value is selected, turning the encoder
wheel changes the value of the selected digit as identified by the
arrowandredtext. Tochangethedigitofinterest,eitherusethe<
or>buttons(Rev8+)orpresstheencoderwheeltochangetodigit
selection mode. Inthismode,thecurrentlyselecteddigitisshown
onablackbackground,andischangedbyturningtheencoderwheel.
Pressingtheencoderagainreturnstovalue modification mode.
The options menu (Figure 2.4) allows the device configuration to
be adjusted. In particular, the power limitappliedto eachchannel
shouldbesetasperthedesiredapplicationbeforeuse(seealsothe
LIM command). Theethernetsettingsofthedevicecanalsobeset
usingthisinterface,includingwhethertoenableDHCPandthefall-
backstaticIPaddressofthedevice. Wheninuse,thenetworkstatus
isdisplayedonthedisplayfooter,andonceconnecteddisplaysthe
currentIP address. Notethatthe“Restartethernet”commandmust
beusedbeforechangesintheethernetmenuwilltakeeffect.
Eachchannelofthedevicecanbeturnedonoroffusingthepush-
buttons on the left of the front-panel. Each channel also has an
associatedmulti-colourstatusLEDindicatorwhosecolourshowsthe
currentoutputstateofthechannelasfollows.
Colour DDS signal Amplifiers
Off 7 7
Green 3 3
Yellow 3 7
Blue 7 3
Purple Debugmode
Red Errorstate
Theoverallbrightnessofthedisplaycanbesetwiththe“contrast”
valueintheOptionsmenu. Thedisplayalsoincludesa“sleep”timer
thatdimsthedisplayifithasn’treceivedinputinagivenperiodof
time. Thisfeaturecanbedisabledbysettingthesleeptimervalue
to0.

8Chapter 2. Connections and controls
2.2 Rear panel controls and connections
90-264 Vac
47-63 Hz
RF OUT 1
MON 1 MON 2
Model:
Serial No:
RF OUT 2 CLK IN
FM/PM 1 FM/PM 2
AM 2AM 1
IEC power in TheARF iscompatiblewithallstandardAC powersystems,from90
to264Vand47to63Hz. Themaximumcurrentdrawisabout1A.
Fan TheARFhasthreetemperature-controlledfansdirectingairflowover
theRF poweramplifiersandtheFPGA,exhaustingthroughtherear
vent. Ensurethattheventdoesnotbecomeblocked.
RF OUT SMA connectorsfortheprimaryRF outputs. Shouldbeconnectedto
a50Ωload. Mustnotbeshort-circuited.
MON SMA connectorsfor“monitor”RF outputs,whichare−20dBccopies
ofthemainoutput(whenhigh-impedanceterminated).
AM/FM/PM SMA analog inputs, nominally for frequency and amplitude modu-
lation (see chapter 5). These inputs can also be used for laser
noise-eaterorfrequencystabilisationapplications(seechapter6).
CLK IN TheARF canbesynchronisedtoahigh-performanceexternalclock
input via this SMA connector and software commands (see §C.8).
The input is 50Ω terminated, and the provided reference must be
between−10and+10dBm(preferablysquare-wave).
DE15 The DE15 connector provides basic I/O functionality (§7.1). There
areTTLinputsforquicklysuppressingtheRFoutput,andTTLoutputs
forcontrollingexperimentaldevicessuchasshutters. Twogeneral-
purposeanalogueoutputsarealsoavailableformonitoringpurposes.

2.3 Internal DIP switches 9
The XSMA breakout board is available to provide convenient SMA
connectorsforeachI/Ochannel(§7.3).
RJ45/USB-A Ethernet(TCP/IP10/100Mb/s)andUSB communicationsjacks.
2.3 Internal DIP switches
FourDIP switchesareprovidedtoassistindiagnosisandrecovery
oftheARF/XRFunits. Theyshouldbeleftindefaultconfigurationfor
regularoperation.
WARNING ThereispotentialforexposuretohighvoltagesinsidetheARF/XRF.
Takecarearoundthepowersupplyandensurethatobjects,partic-
ularlyelectricallyconductingobjects,donotentertheunit.
CAUTION Thecovershouldbereplacedbeforepoweringontoensureproper
airflowandcooling.
OFF ON
1Normaloperation Firmwareupdatemode
2DisableFPGA Normaloperation
3Usefactorysettings Normaloperation
4Normaloperation Factoryreset
DIP 1 Default OFF. If switched ON, the unit will start in firmware upload
mode(see§B.3).
DIP 2 DefaultON.SwitchOFFtodisabletheFPGAfordiagnosticpurposes.
DIP 3 DefaultON.SwitchOFF tousedefaultdeviceandnetworksettings.
DIP 4 Default OFF. Switch ON and reboot to restore the unit to factory
versionandconfiguration.

10 Chapter 2. Connections and controls