Program Mode
Algorithm Basics
6-13
Algorithm Basics
PresstheALGsoftbuttonintheProgramEditortotakeyoutotheAlgorithm(ALG)page.The
basicdefinition:analgorithmisthe“wiring”(signalpath)ofasampletotheaudiooutputs,
throughaseriesofdigitalsignalprocessing(DSP)functionsthatyouselect.ThePC3K’s
algorithmsarethe
coreofVariableArchitectureSynthesisTechnology.TheDSPfunctionsare
synthesistools(filters,oscillators,etc.)thatyouassigntothevariousstagesofthealgorithm.The
DSPfunctionsyouchoosedeterminethetypeofsynthesisyouuse.
Eachofthe59availablealgorithmsrepresentsapresetsignalpath. Withournew
Dynamic
VASTfeature,youcaneditanypresetsignalpathandmakeyourown,uniquealgorithms,but
thatwillbeexplainedfurtheroninthissection.TakealookatAlgorithm1inthediagrambelow.
It’soneofthesimplestalgorithms.
TheDSPfunctionsarerepresentedbytherectangularblocks.
Thelinesconnectingtheblocks
togetherindicatestheflowofthedigitalsignalfromlefttoright;theyrepresentwhatwecallthe
“wire”ofthealgorithm:theactualphysicalpaththatthesignalfol lowsthroughthealgorith m.
SelectingdifferentalgorithmscanbecomparedtoconnectingdifferentDSPfunctionswith
differentwiringdiagrams.
Thinkoftheleftsideofeachblockasitsinput,andtherightsideasitsoutput.Dependingonthe
algorithm,thesignalmaysplitintotwowires,enablingpartofthesignaltobypasscertain
portionsofthealgorithm.Splitwiresmayrejoinwithinthealgorithm,
ortheymaypassallthe
waythroughassplitsignals.Ifthelastblockhastwowiresatitsoutput,wecallitadouble‐
outputalgorithm.Ifithasonewire,it’sasingle‐outputalgorithm,eveniftherearetwowiresin
earlierportionsofthealgorithm.
Each
blockofthealgorithmrepresentsacertainfunctioninthesignalpath.Ineverynon‐
cascadedalgorithm(seeAltInputforAlgorithms(CascadeMode)below),thesignalflowsfirst
throughaone‐stageDSPfunctionthatcontrolsthepitchofthesamplesinthekeymap(this
functionisrepresentedasa
blocklabeledPITCHintheupperright‐handcornerofthedisplay).
Infact,thefirstDSPfunctionineachalgorithmalwayscontrolspitch,eventhoughitdoesn’t
applyineveryinstanceand,aswillbeexplainedlaterinthissection,itisbypassedincascaded
algorithms.Similarly,thelast
DSPfunctionalwayscontrolsthefinalamplitudeofthesignal
(thisfunctionisrepresentedasablocklabeledAMPintheupperright‐handcornerofthe
display).
Thenumberoffunction‐parametersaDSPfunctioncanhavedependsontherelativesizeofits
function‐blockontheAlgorithmpage;
forinstance,afunction‐blockthatisthreeslotslongcan
haveuptothreefunction‐parameters,whereasafunction‐blockthatistwoslotslongcanhave
uptotwofunction‐parameters.Foreachfunction‐parameter,there’sacorresponding“subpage”
onboththeDSPCTLand DSPMODpages.OntheDSPCTL
subpages,therearefineadjustand
hard‐wiredparameterswithwhichyoucanmakefixedadjustmentstothefunction‐parameter.On
theDSPMODsubpages,thereareprogrammableparametersthatyoucanassigntoanycontrol
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