Olson Technology OTM-3000-I User manual

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OTM-3000-I
FREQUENCY AGILE
TELEVISION MODULATOR
INSTRUCTION MANUAL
025-000137 REV B 8/29/01
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www.olsontech.com
PAL I STANDARD

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OTM-3000-I
FREQUENCYAGILETELEVISIONMODULATOR
PALISTANDARD
1) INTRODUCTION
TheOTM-3000-Iisafrequencyagiletelevisionmodulatorwithanoutputfrequencyrangeof48.00MHz
through445.25MHz. Frequenciesare selectablein 1/4MHz incrementsby frontpanel DIPswitches.Arear-
paneltoggle switchselects betweenranges of48.00 through418.25 MHz and418.50 through445.25MHz.
FrontpanelcontrolsalloweasyadjustmentofvideoandaudiomodulationlevelsaswellasRFoutputandaural
carrierlevels.LED’sindicateovermodulationofthevisualorauralcarriers.
TheOTM-3000-Ioffersexcellentinputsensitivityand highoutput level,typically +60dBmV. Also,thisunit
hasveryhighout-of-bandcarriertonoise ratio(>77dB)and usesSAWI.F.filtering,whichallowsvirtuallyan
unlimitednumber of modulatorstobe combined withoutthe need forexternalbandpass filters. The OTM-
3000-Ihas low power consumption(14watts @ 240VAC) forreliablelong term operation.
2) INSTALLATION
Mount the OTM-3000-I in a standard equipment rack or equivalent as required. It is suggested that blank
spacesequivalenttoasingleunitheightbeprovidedaboveandbelowthemodulatortoallowadequatecooling
airtocirculate.
TheOTM-3000-I is configuredfor 240VACinput powering.The colorcoding of thewires in theline cord
isto European standards althoughtheplug is a USAtype. The plug canbechanged to a propertype(Be
sureto observe proper color codeconnection)or an adapter may beutilized.
3) CHANNELSELECTION
Channelselectionismadebyproperlysettingthetow 8-positionDIPswitchestothecorrespondingfrequency
code.
Tosettheunit foragivenfrequency,selectthe desiredfrequency codefromthelistof frequencycodes atthe
endofthismanual.Removethesmallcoverfromthefrontpanelunder“CHANNELSELECT”andsetthetwo
8-positionDIPswitches fromleft toright (Seefigure1).
TheOTM-3000-I hasanoutput frequencyoffsetfeature which isnot requiredinPALIapplications. Itis
mentionedhere forreference only.Fixedoffsetsareselectedbythelast 3right handpositions ofright hand
switch.Leavethisswitchin the0 KHzoffsetpositionas illustratedbelow.

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Figure1
FRONT PANELDIPSWITCHES
0= Switch inDOWNPosition
1= Switchin UPPosition
Thelast 3DIP switches onthe farrightare usedto selectoffsetoperation withcertain versions ofthe
OTM-3000. Onthe OTM-3000 I, the switch should be left set as shown below.
4) VIDEOMODULATIONADJUSTMENT
A) Connect avideosource of approximately1Vp-p to thevideo input connector (75ohms input Z)on
therearpanel. Thevideoshouldbeof areasonably brightscene toensure settingat peakmodulation
levels.
B) Rotate thevideomodulationleveladjustcontrolslowlyclockwiseuntilthevideoovermodulation
LEDjustturns on.The lightmayblinkwithdifferences inaveragepicturelevel. CAUTION: Ifthe
modulationisset toohigh,compression orlackof contrastwilloccur duringhighintensity scenes.
5) AUDIOMODULATIONADJUSTMENT
A) Connect anaudio sourceof300mV p-p(minimum)tothebalanced audioinputconnector(600ohms
inputZ) on therear panel. The sourceshouldbe typical oftheprogram material tobe carried.
B) RotatetheaudiomodulationleveladjustcontrolslowlyclockwiseuntiltheaudioovermodulationLED
justbeginsto blink. CAUTION:OvermodulationcanresultinseveredistortioninsomeTVsets. Set
thiscontrol atpeak programlevels.
6) RFANDAURALCARRIERLEVELADJUSTMENT
A) Usingafieldstrengthmeter orspectrumanalyzer,setthevideocarriertothedesiredlevelwiththeRF
outputleveladjustcontrol.
B) Tunethe fieldstrength metertothe auralcarrier (6.0MHzabove thevideo carrier).

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C) Adjust the aural carrier level control to the desired level, typically 15dB below the video carrier.
CAUTION: Reducingthe visual/aural carrierratio to lessthan 15dB canresultin highout-of-band
spurioussignalsinadjacentchannels.
7) MISCELLANEOUS
A) Thisunitis equippedwithvideoandaudio I.F.loops. Bothloopsareconnected withtwotypeFshort
jumpers. Ifthese become disconnectedormisplaced, then theOTM-3000-I will not performprop-
erly.
B) IfascramblingunitisutilizedwiththeOTM-3000I,followtheinstructionsassociatedwiththescram-
bler.The videoI.F. output level is +40dBmV,andtheaudio carrier level is determined by the aural
carrierlevel adjustment- typically+17dBmV@15dBA/Vratio.
C) This unit is equipped with a 0.25 slo-blo fuse.Forcontinuedsafetyandtomaintainproper perfor-
manceofthe unit,pleasereplace onlywithanequivalentfuse.
D) A -20dB testpoint(typeF connector) is provided on the rearpanel.

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MODULATORSWITCHSETTINGCALCULATION
The output frequency select switches may tune a unit in either 1MHz or 250KHz steps depending on the factory
presettingofstep size.Tocalculatetheswitchsettings foraunit,theformula isas follows:
N = OUTPUT FREQUENCY + 2ND IF FREQUENCY 2ND IF FREQUENCY
STEP SIZE IN MHz ALL NTSC = 612.75
ALLPAL = 605.75
ORFOR1MHzSTEP SIZE
N = OUTPUT FREQUENCY + 612.75
1
OR FOR .25MHz STEPSIZE
N = OUTPUT FREQUENCY + 612.75
0.25
Convertthenumber“N”tobinarywith theleast significantbit ontheleft,(notthe rightas iscustomary). This binary
numberrepresents the switchsettingswith 1 =up, 0 =down.
BINARYCONVERSION WITH LEASTBIT ON LEFT.
————————————————————————————————————————————
EXAMPLE: CALCULATE 437 INBINARY
STEP1) CONSULT CHART FOR LARGESTNUMBER LESSTHAN OR EQUALTO 437. (256)
STEP2) CONSULTCHARTTOFIND NEXTLARGEST NUMBERWHICHADDED TO256 IS LESS
THAN OR EQUAL TO 437. (128 + 256 = 384)
STEP3) CONSULTCHARTTOFIND NEXTLARGEST NUMBERWHICHADDED TO384 IS LESS
THAN OR EQUAL TO 437. (384 + 32 = 416)
STEP4) CONSULTCHARTTOFIND NEXTLARGEST NUMBERWHICHADDED TO416 IS LESS
THAN OR EQUAL TO 437. (416 + 16 = 432)
STEP5) CONSULTCHARTTOFIND NEXTLARGEST NUMBERWHICHADDED TO432 IS LESS
THAN OR EQUAL TO 437. (432 + 4 = 436)
STEP6) CONSULTCHARTTOFIND NEXTLARGEST NUMBERWHICHADDED TO436 IS LESS
THAN OR EQUAL TO 437. (436 + 1 = 437)
STEP7) EACH NUMBER CHOSEN = CODE 1AND EACH NUMBER NOT CHOSEN = CODE 0.
X X X X X X
1 2 4 8 16 32 64 128 256 512 1024 2048 4096 8192
437 = 1 0 1 0 1 1 0 1 1 0 0 0 0 0

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OTM-3000-PALI -DipSwitch Settings
Down=0 Up=1 (.25MHz Steps)

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