AudioInput

18.4.3Configuring

SetThreadInvokingtrueifyouwantAudioInputinstancetosynchronizeitseventstothemainUI threadautomaticallybutmakesurethatAudioInputinstancehasavalidparentcontrol.ThreadInvokingis falsebydefaultsodonotforgettocallControl.Invokemethodif youupdateGUI inyourDataGeneratedeventhandler.

If youwantto useotherWindows’recordingdevicethanthedefaultone,setRecordingDeviceproperty.YoucangetallavailablerecordingdevicesbyusingAudioInput’sstaticmethodGetRecordingDevices.

VolumecanbecontrolledthroughVolumeproperty.Validvaluesarefrom0to100where0meansmuteand100maximumvolume.YoucansetvolumealsowhenAudioInputinstanceisenabled(i.e.generatingsamples).

If youwanttousedifferencesamplingratethanthedefault(44100Hz)thensetSamplesPerSecond

property.SettingthispropertywhileAudioInputinstanceisenabledhas noeffect.

Tousemonoaudioinsteadofstereo(default),setIsStereotofalse.Settingthispropertywhile

AudioInputinstanceisenabledhas noeffect.

If youprefer8bitsper sampleratherthan16(default),setBitsPerSampleproperty8.Validvaluesare 8and16(default).ThislimitationcomesfromPCMwaveformat.SettingthispropertywhileAudioInputinstanceisenabledhas noeffect.

18.4.4Starting

TostartAudioInputinstanceyoucaneithersetIsInputEnabledpropertytrueorbycallingStartmethod.WhenDataGeneratedeventprovidesyouwitha newsetofaudiosamplesyoucane.g.renderthemusingLightningChartUltimateinstance.

When youwant tostopAudioInputinstance,setIsInputEnabledfalseorcallRequestStopmethod.RequestStopmethoddoesnotstopinstantly.ItjustsignalsAudioInputinstancetostopassoon asitis possible.Ifyouneedto waituntileverythinghas beenstoppedthen waitforStoppedeventtogettriggered.Youneedtohavesubscribedtoit.

18.5Usage(WPF)

This chapterdescribestheusageofWPFversionofAudioInputclass.WPFversionofAudioInputworksbasicallythesamewayasWinFormsversion.However,therearea coupleofthingsthataWPFuser is goodto knowandthesethingsaredescribedinthischapter.

18.5.1Creation

CreateanewAudioInputinstanceeithermanuallyincode-behindorbydragginganddroppingit

fromVisualStudio’stoolboxonto yourwindow,usercontroletc.

If youdonotneedtoshowGUI (i.e.youuseyourownoryoucontrolAudioInputobjectfromyoursourcecode)thenuse AudioInputfromArction.WPF.SignalToolsnamespace.This particularclassis derivedfromFrameworkElementandall itspropertiesarebindable.Foryourconvenience,after

youhaveinstalledLightningChartUltimateSDK,Arction.WPF.SignalTools.AudioInputcanalsobe foundfromVisualStudio’stoolboxso youcandropitonyourwindows,usercontroletc.andthen movetheelementwhereveryouneeditinyourXAMLcode.NecessaryXMLnamespacewillbeaddedautomaticallythisway.

Thereisalsoaready-madeGUI forAudioInput.ItcanbefoundfromArction.WPF.SignalTools.GUInamespace.YoucanfinditalsofromVisualStudio’stoolboxafteryouhaveinstalledLightningChartUltimateSDK.Notethatthisisjusta GUI forArction.WPF.SignalTools.AudioInputclassbutit containsaninstanceofArction.WPF.SignalTools.AudioInputclassandyoucanaccessitthroughInputproperty.I.e.youdonothaveto createanewseparateArction.WPF.SignalTools.AudioInputinstance.

It isrecommendedto setLicenseKeypropertyso thatyourAudioInputinstanceusesanexplicitlicensekeyinsteadoftryingtofindonefromWindows’registry.Note,ifyouareusingatrial version/licensethenyoucanleaveLicenseKeypropertytoitsdefaultvalue.

19.AudioOutputcomponent

AudioOutputcomponentallowsusertoconvertSystem.Doublesignaldataintoanaudiostreamwhichis then playedbackthroughspeakers,orsenttoLine-outconnectorofsounddevice.

19.1Properties

Balance–Getsorsetsaudioplaybackbalance.Validvaluesare between-100to100.-100means thataudioisplayedonlythroughtheleftspeaker.0meansthatbothspeakersoutputaudio.100means that audioisplayedonlythroughtherightspeaker.

BitsPerSample–Getsorsetshowmanybitsareallocatedper sample.Supportedvaluesare8and16.If othervalueisused,16isusedinstead.IssettablewhenIsOutputEnabledisfalse.

IsOutputEnabled–Getsorsetsthe stateofthisinstance(i.e.startsorstopsit).Settingthispropertytrue isthe sameascallingStartmethodwherefalseisthe sameas callingStopmethod.

IsStereo–Getsorsetswhethertousetwochannels(stereo)orjustone(mono).Issettablewhen

IsOutputEnabledisfalse.

LicenseKey–Getsorsetslicensekeystringin normalorencryptedformat.

PlaybackDevice–Getsorsetsthecurrentplaybackdevice.Issettablewhen IsOutputEnabledisfalse.Bysettingthispropertynull,Windows'defaultplaybackdeviceisused.

SamplesPerSecond–Getsorsetssamplingfrequency.Is settablewhen IsOutputEnabledisfalse.

Volume–Getsorsetsvolume(0-100).IssettablewhenIsOutputEnabledisfalse.

20.SpectrumCalculatorcomponent

SpectrumCalculatorcomponentallowsconversionbetweentimedomainandfrequencydomain.

Figure20-1.Exampleofsourcesignaldata(top)convertedtofrequencydomain(bottom).Signalsamplingfrequency=300

Hz,thusfrequencyscaleis300/2=150Hz.Thestrongsinebaselineis10Hz(10cycles/sec).Smallersignalof100Hzisadded

asnoise.Bothspikesarefoundinthepowerspectrum.

Thefollowingpublicmethodsareavailable:

• CalculateForward(double[]samples,outdouble[]fftData):ConvertstimedomainsignaldatatofrequencydomainbyusingFFT.OutputfftDatacontainsalsonegativevalues.Inputandoutputdata arraysmustbeofequallength.Thelengthistheresolutionofthedata,spreadingfrom0Hzto samplingfrequency/2withequalfrequencyintervalbetweenoutputvalues.

• CalculateForward(float[]samples,outfloat[]fftData):likethepreviousmethod,butforsingleaccuracyfloatingpointvalues.

• CalculateBackward(double[]fftData,outdouble[]samples):Convertsfrequencydomaindatatotimedomain.MakessignalsamplesfromFFTdata,samplecountequalsinputfftDatalength.

• CalculateBackward(float[]fftData,outfloat[]samples:likethepreviousmethod,butforsingleaccuracyfloatingpointvalues.

• PowerSpectrum(double[]samples,outdouble[]fftData):Calculatespowerspectrumofsignaldata.Sameas CalculateForward,butwith absoluteoutputvalues.

• PowerSpectrum(float[]samples,outfloat[]fftData):like thepreviousmethod,butforsingleaccuracyfloatingpointvalues.

• PowerSpectrumOverlapped(double[]samples,intfftWindowLength,doubleoverlapPercent,outdouble[]fftData,outintprocessedSampleCount):calculatespowerspectrumbyshiftingthe calculationwindowsinsidesourcesignalsamplesdata,byoverlappercent.SignaldatamustbelongerthangivenFFTwindowlength.The outputFFTdataislengthoffftWindowLength,sonotnecessarilysamethanthelengthofsourcedata.Theoutputdataisabsolutevalues.

• PowerSpectrumOverlapped(float[]samples,intfftWindowLength,doubleoverlapPercent,outfloat[]fftData,outintprocessedSampleCount)