HP-320A-Brochure 电路图.pdf

DISTORTION MODEL320A ANALYZER TheModel320AR ANEWINSTRUMENTFORDISTORTIONMEASUREMENTS SHOWSTYPEOFDISTORTIONASWELLASAMOUNT STANDARDMODELSFORMEASUREMENTSATTWOORSIXFREQUENCIES ANYFREQUENCIESFROM50TO10,000CYCLESAVAILABLE SAVESTIMEINDEVELOPMENTANDPRODUCTIONTESTING USES:The Model320ADistortion Analyzerisa simple andconvenientdeviceforstudyingandmeasuringthe harmonicdistortioninaudiofrequencyapparatus.Itis particularlysuitablefordevelopmentworkbecausewith itthecharacterandtypeofdistortioncanbedetermined atthesametimethedistortionisbeingmeasured.Itis excellentforproductionworkbecauseitiseasytooper- ateandprovidesarapidandaccuratecheck for normal operation. TheModel320isessentially acomparisondeviceusedto comparethedistortioncontentofthewavewiththefun- damentalvoltage.Whenthiscomparisonismadewith acathoderay oscilloscopethetypeofdistortioncanbe observed.The variousorderharmonicswillshow up on theoscilloscopepattern,thehumvoltageandnoise volt- agewillappear,andagreatdealofinformationabout thevoltagebeinganalyzedcanbeobtained.Inthisway theModel320isavaluableinstrumentnotonly when usedalonebutalso whenused withotherequipment which Measuresthetotalr.m.s.distortiondirectly. DESCRIPTION:Thedistortionanalyzerconsistsoftwo bandelimination filters,oneformeasurementsat400 cyclesandoneformeasurementsat5,000cycles,anda calibratedattenuator.Withthevoltagetobeanalyzed adjustedtotheproperfrequencythefundamentalis eliminatedcompletely.The residualvoltagecontaining theharmonicscanthenbeobservedwith an oscilloscope ormeasuredwith a sensitivemeter.Whenthefrequency hasbeenadjustedsothefundamentaliseliminated,the elimination filterisswitchedoutandacalibratedattenu- atorisintroduced.Thentheattenuationofthefunda- mentalisincreaseduntilthefundamentalvoltagehasthe samemagnitudeastheresidual harmonics alone. MEASUREMENTS:Withtheproperadjustment,theset- tingoftheattenuatorontheinstrumentgivesdirectlythe amplitudeoftheharmonicvoltageindecibelsbelowthe fundamental.Whenan oscilloscopeisusedforthede- tector,measurementsoftheharmonicvoltagerequire T-102 RadioFans.CN 收音机爱 好者资料库 someexerciseofjudgment.The residualharmonicvoltage willcontainsharppeaksinmany cases.These peaks con- tainvery littleenergyandthis shouldbetakenintoac- countinestimatingther.m.s.oraveragevalueofthe residual harmonicvoltage. Ifmoreaccuratemeasurementsaredesiredametermay beusedinplaceoftheoscilloscopeorinconjunctionwith it.Withsuch ameterthedistortionmeasurementsmay bemadewith asgoodaccuracyascanbeobtainedwith themoreexpensive distortionmeters. DISTORTIONANALYSIS:Fordistortionanalysisan oscilloscope shouldbeused asthedetector.Asthefre- quencyisadjustedtoeliminatethefundamental,thesec- ond,third,andhigherorderharmonicswillappearsuper- posedonthefundamentalvoltage,andfromthetrace obtainedtherelativeimportanceofthesecomponents canbedetermined. Byplacingtheresidual harmonicvoltageonthevertical platesoftheoscilloscopeandthefundamentalvoltageon thehorizontal plates,theparticularpartofthecycleat whichthedistortionoccurscanbedetermined. Thisinstrumentisvery usefulfordevelopmentormain- beobservedwhilechangesarebeingmadeinthecircuit undertest.Commonf.ormsofdistortionsuch aspeak clipping,sharpcut-off,transformersaturation,andpara- siticscanbediscoveredquicklyandcorrected. FREQUENCY RANGE: INPUT IMPEDANCE: DISTORTIONRANGE: DETECTORSENSITIVITY: MOUNTING: SPECIFICATIONS TheModel320Aisdesignedformeasurementsat400and5000cps.The Model 320Bisdesignedformeasurementsat50, 100, 400, 1000, 5000,and7500cps.Filters forotherfrequenciescanbesuppliedon specialorder. Theinputimpedanceisatleast20,000ohms.Abridgingtransformermaybeusedto increasetheinputimpedance. The filter circuitswillprovidemorethan60dbofattenuationofthefundamental. Distortion values as low as0.110ofthefundamentalmaybemeasuredwith adetector ofsufficient sensitivity. The sensitivityoftheinstrumentisdeterminedbythedetector.Thedetectorshould giveareadableindicationon0.110ofthefundamentalif harmonicsof0.110areto bemeasured.Thedetectorneednotbecalibratedbecauseitisusedforcomparison only.The usual oscilloscope with aonestageamplifierissufficiently sensitiveto measure0.370ofa 30 voltfundamental.Forproperoperationoftheinstrumentthe inputimpedanceofthedetectormustbe100,000 ohmsorgreater.Anamplifier may beusedbetweentheinstrumentandthedetectortoincreasethesensitivity.The only requirementson such an amplifierarethatit must passthehighestharmonic which isofinterestandthatit have a highimpedanceinput.Itneednotbefreefrom distortionotherwise. TheModel320Aismounted,inanattractiveoakcabinetwiththepanelfinishedin wrinklegrey.The Model 320AR fitsthestandard19 relay rack with%spacing. Thepanelisfinishedinwrinklegreywithmachineengraveddesignations. ModelMountingLengthHeightDepthWeightPrice 320ACabinet1286 8# $60.00 nOARRelay Rack195Y45Y2 8# $65.00 320BCabinet168 615#$145.00 320BRRelayRack 1971020#$150.00 Pricesarenetf.o.b. Palo Alto,California. Pricesanddatasubjecttochangewithoutnotice. December10,1940. HEWLETT-PACKARDCOMPANY 481PAGE MILL ROAD PALO ALTO,CALIFORNIA I RadioFans.CN 收音机爱 好者资料库