Olson Technology OTOT-1000 User manual

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OTOT-1000&OTOT-1000E
WIDE-BANDLOW-COSTOPTICALTRANSMITTERS
1,000MHzBANDWIDTH/OPTICALOUTPUTPOWERFROM
+3dBm(OTOT-1000-3) to +15dBm(OTOT-1000-15)
INSTRUCTION MANUAL
025-000554REVX7 09/03/09
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E-Mail: [email protected]
www.olsontech.com

025-000554REVX7 Page 2
TABLEOFCONTENTS
INTRODUCTION Page 4
INSTALLATION Page 4
Installation/EnvironmentalConsiderations Page 4
OpticalConnectorsandCleaning Page 5
InternalControls Page 5
ExternalControlsandTestPoints Page 6
InitialSetup Page 6
InputDrivevs.ChannelLoading Page 7
ReducingLinkGain Page 7
ACCESSORIES Page 8
RELATEDOLSONTECHNOLOGYPRODUCTS Page 8

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SAFETY WARNINGS
LASER RADIATION
NEVER USE ANY OPTICAL INSTRUMENT TO VIEW THE OUTPUT OF THE LASER
TRANSMITTER.“OPTICALINSTRUMENT”INCLUDES MAGNIFYINGGLASSES,ETC.
NEVERLOOK INTOTHEOUTPUT OFTHELASER TRANSMITTER
NEVERLOOKINTOTHEOUTPUTOFAFIBERCONNECTEDTOALASERTRANSMITTER.
NEVERLOOK INTO ORUSEANYOPTICALINSTRUMENTTOVIEWTHE DISTANTEND
OFAFIBER THAT MAY BE CONNECTED DIRECTLY OR VIAAN OPTICALSPLIT, TOA
TRANSMITTER THAT MAYBE OPERATING. THIS SPECIFICALLYAPPLIES TO FIBERS
THATARE TOBE CONNECTED TO RECEIVERS (SUCHAS THE OTPN-1000) OR OTHER
DEVICESATANYDISTANCEFROMTHE LASERTRANSMITTER.
HIGHVOLTAGE
Theinsideof the OTOT-1000containsnouserserviceableparts.There is exposedhighvoltageinsidethisunit.Only
factoryservice techniciansshouldopenthe unitwithpowerapplied.
FIREHAZARD
TheACline input fuse is contained in the IEC 320 power input connector.This fuse is a 250V,0.5A,5x20mm,slow
blowfuse.To avoid a risk offire,thisfuseshouldbereplacedonlywithanidenticallyratedfuse.
SHOCKHAZARD
TheOTOT-1000is designed for indoor use only. Direct exposure tomoisture mustbeavoided.
offorpreferably,disconnectedwhenevertheopticalconnectorcoverisopenedandthereisnoinstalledfiber (as
whenthe fiber connectorisbeinginstalled orremovedfromthetransmitter connector).
TheOTOT-1000 laser transmittersemitinvisibleradiationthat cancause
permanent eye damage. AVOID DIRECT EXPOSURE TO BEAM.
Operatethe transmitter onlywiththeproper optical fiberinstalledinthe
transmitteropticalconnector. Power to theOTOT-1000shouldbe turned

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INTRODUCTION
TheOlsonTechnologyOTOT-1000 is a higherperformanceindoorwidebandlasertransmitterwith an RF passband
of48to1,000MHz.The OTOT-1000 also offers enhanced CATVperformance.Thesetransmittersareintendedfor
indoorapplications.Theycombinethetransmitter and universalACpower supply inonecompacthousingthat has a
footprintof7.5"x5.5" x 1.6". The optical output power and bandwidthofeachtransmitterisasfollows:
OTOT-1000-3 +3dBm,48-1,000MHz
OTOT-1000-6 +6dBm,48-1,000MHz
OTOT-1000-8 +8dBm,48-1,000MHz
OTOT-1000-9 +9dBm,48-1,000MHz
OTOT-1000-10 +10dBm, 48-1,000MHz
OTOT-1000-12 +12dBm, 48-1,000MHz
OTOT-1000-13 +13dBm, 48-1,000MHz
OTOT-1000-14 +14dBm, 48-1,000MHz
OTOT-1000-15 +15dBm, 48-1,000MHz
Eachtransmitter hasauniversalpower supplyandwilloperate from90to240VAC at50or60 Hzandconsumesabout
10Watts.
TheOTOT-1000isanidealforwardsignalsourcefortheOTPN-1000HighSensitivity Indoor Node and will allow
for an optical path loss of 21 dB or more. Test points are provided for laser output power and current to allow for
historicalreview ofoperatingparameters.AnRFtestpoint isprovidedtoallow propersetupandfor historicalreview.
Positivecoolingisprovidedbymeansofasmall,high-MTBFfan,whichmaybereplacedinthefieldwithoutinterrupting
theoperation of theunit.
TheOTOT-1000hasflangeson thebottomtoallow mountingittoaflat surface.TheavailableOTLL-RMKIT-1 will
allowmountinguptothree of these units in a standard 19" rack.
INSTALLATION/ ENVIRONMENTALCONSIDERATIONS
The OTOT-1000 transmitters are specified to operate from -10°C to +55°C. They usually do not require an air-
conditionedenvironment. They shouldbemountedinan adequately ventilatedarea.Likeallelectronic equipment,it
willgenerally havealongerlife spanifitis notoperatedatthe upperlimitofthe temperaturerange.Installationin wet
areas or areas of extremely high humidity should be avoided. Extremely dirty or dusty areas should be avoided if
possible.Objectsordebris should not be allowedtoblocktheopeningsinthehousing or the fan. The unitshouldnot
beinstalledinareas that are accessible to children.
TheOTOT-1000maybeinstalled and operated in any positiononaflatsurface.The unithasfourslotsinthebottom
plateto accommodate mounting hardware. Ifmountingrequires a wood screw,use #6 or #8 (maximum)pan-head
sheetmetalscrews.Thesearecommonlyavailableathardwarestores.Ifmountingwithamachinescrew(totapped
holes),use 6-32 pan-headscrews.

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FIGURE1 -OTOT-870-xx andOTOT-1000-xxMOUNTINGDIAGRAM
OPTICALCONNECTORSANDCLEANING
ThestandardopticalconnectorisanSC/APC.InordertouseFC/APC connectors, you must order a conversion kit,
OTLL-SCFCKIT.ThestandardopticalconnectorlocationisontheoppositesidefromtheRFconnector.Theconnector
canbemovedtothe other side by swapping it with acoverplate.Onlyascrewdriverisrequired for this operation.
The fiber ends can be damaged by the insertion of contaminated connectors. Some types of customer damage to
connectorsarenot covered under warranty.Fiber connectors shouldneverbeleft uncovered. Prepackaged alcohol
wipesarethe most convenient meansofcleaningopticalconnectors.Cleanalcohol and lint freewipesorswabsmay
alsobe used. INTERNAL CONTROLS
Therearenointernaluseradjustments.Theonlyreasontoopentheunitwouldbetomovethefiberconnectortothe
other end of the unit. This should be done before the unit is attached to a rack mount kit. The unit should not be
operatedforlong periods oftimewithoutatop cover.This can causeRFradiationandingressproblems.The internal
coolingisalso reduced whenuncovered.
Be sure to replace and tighten all top cover screws. Oscillation or RF radiation can be caused by loose or missing
screws.
There is no user adjustable internal laser power adjustment.Any change to the laser power will result in poorer
modulationcharacteristics andreducedlink performance.

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EXTERNALCONTROLSANDTESTPOINTS
Thereare twoexternalDCtest points.Onereadslaser currentat1Vper 50mA.Atypical lasercurrentof30mAwould
read 0.6Vat this test point. The laser power test point is 0.1Vper mW. This is for historical tracking. The optical
powermeterisamuchmoreaccuratemeansofmeasuringpower.Bothofthesetestpointsshouldbemeasuredwith
ahighimpedancevoltmeter.
Thereis an external multi-turnRF input attenuation controlonthe front panel.Thisis set at thefactory to the fully
clockwisepositionwhichyieldsminimumattenuation.Theusercanadd4dBofattenuationwiththiscontrolwhich
allowstheinputRF level to be up to 4dBhigherthantherecommendedlevels..
Thereisanexternal75ΩRFtest point. This test point measuresthelaserdrivelevel,nottheRFinputlevel.Thistest
point has been adjusted to read a very specific level when the RF drive has been adjusted for optimum optical
modulation.
For the factory tested input loading of 77 analog and 42 digital channels, this test point should read +10dBmV at
547.25MHzwith theRFgain controlpotisfullyclockwise.Atthisfrequency, thelossin theconnectingcableandany
impedancematchingdevicescanbevery significant. See the section on input loading for the proper test pointlevels
withotherinputconditions.
INITIALSETUP
Mounttheunit and applypower.The laser is temperaturecontrolled.The unitwilloperateimmediatelyafterturn on,
but requires about 5 minutes to temperature stabilize. Measure and record the optical output with a power meter.
Measureandrecordthe laser current and optical power readingsattheexternaltestpoints.
Measureand recordtheRFinput levels.CAUTION:Atthisfrequencyrange thelossandslope ofcoaxcablesisvery
significant.Thebestapproachistoconnectthe cablethatwillgototheOTOT-1000inputdirectlytothemeasurement
device.
Theinputsignalsshouldbeflatwithin±1dB,preferablywithin±0.5dB.Responsesworsethanthiswillresultinreduced
C/Nandordistortionperformance.
Specialattentionmustbepaid to the relative level of thechannel thatisusedtosettheRF gain and thus set the laser
modulation.Ifthischannelismuchhigherthantheotherchannels,thensettingtheRFgainwillcausetheotherchannels
tobe lowerthanoptimum, resultinginreducedCNRperformance.Ifthis channelistoolow,thenusingittosetthe RF
gainwill causetheotherchannels tobehigherthanoptimum,resultinginreduceddistortionperformance.A1to2 dB
errorwillcausesignificantlyimpairedperformance.
ConnecttheRF input to the unitandadjustthe RF gain control foralevelthatindicates proper modulation. For the
factorytestcondition,thisis+10dBmVat547.25MHz.Forotherchannelloadings,consultthenextsection.Donot
forgettoaccountfor the loss in the connectingcable.

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INPUTDRIVE vs.CHANNELLOADING
ThelaserRFdrivelevelistheprimarydeterminingfactoroflinkdistortionandCNRperformance.Thebasiclimitation
oninputdriveistotalinputpower.Thefollowingchartsshowtheapproximateinputlevelsversuschannelloading.The
leftaxisshowsthenominalRFinputlevel.Theunitwillworkwithlevelswithin±2dBofthisvalue.Therightaxisshows
thetestpointreadingfor optimum modulation. Figure 2 below is fortheOTOT-1000-3andOTOT-1000-6models.
Figure3onthenextpageisforallotheropticalpowerlevels.
Mostsystemsruntheirdigitalchannelsat6dBbelowtheanalogchannels.Thisisaveryconvenientlevelforcalculating
loading.At6dBdown,simplydivide thenumberofdigital channelsby4and addtothenumberofanalogchannelsto
getthetotalequivalentanalogchannelloading.
Thefactorytestinputis77analogchannelswith42digitalchannelsat6dBdown.Thenumberofequivalentanalog
channelsis77 + 42/4, which equals87.5.Thisisthe 87.5 ch / +17.6dBmVinputpointon the graph.
SomesystemsuseanOMImetertosetlasermodulation.TheOTOT-870’s& OTOT-1000’shave been individually
adjustedforoptimum performance. Setting allunitsforthe same OMI, insteadofusingthe test point, willresultin
reducedtransmitterperformance.Ifthechannelloadingislessthan40,youmaydecidenottoincreasethelevelsbythe
maximumpossible amount.Thiswillprovide improveddistortionatthecostofCNR. Thebestruleof thumbistouse
themaximum possiblelevelsfor longhaullinks, andlowerdrivelevelsasthelinksgetshorter.
REDUCINGLINKGAIN
Shortlinkscanhavereducedperformanceduetoreceiveroverloading.Reducing thelaserRFdrivewillcausereduced
CNRperformance.AttemptingtolowerthelaseroutputpowerwillhavetheevenworseresultofdegradingbothCNR
andIMD.The correct solutionistolowerthereceiver input levelwithanopticalattenuatorsuch as the OTOA-1000.
Itisrecommendedthatthisbedoneatthereceivelocation.
FIGURE2-INPUT LEVELvs.CHANNELLOADING -LOWPOWERUNITS

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FIGURE3- INPUTLEVELvs.CHANNEL LOADING-HIGHPOWER UNITS