Tiptop Z3000 Smzrt VCO - Manual (Page 13)

Frequency Modulation. - Basics
Frequencymodulation(FM)synthesisisatechnique
usedtogeneratemusicallyinterestingsoundsby
rapidlychangingthebasicfrequencyofasound.The
patternofchangeiscreatedbyanotherwaveformwith
afrequencywithintherangeofhumanhearing.
Inpractice,itisassimpleasconnectingtheaudio
outputofanoscillatortothefrequencycontrolinput
ofanotheroscillator.First,anumberofconsiderations
needtobetakenintoaccount:waveformtype,FM
inputtype,frequencyratio,andsynchronization.
Frequencymodulationstartswithtwoormore
oscillators.Thefirst(themodulator)isusedto
modulatethefrequencyofasecondoscillator(the
carrier).Typically,sinewavesareusedbecausethey
are,ideally,freeofharmonics,butmodularsystems
allowfortheuseofotherwaveforms. However,the
morecomplexthemodulatingwaveformisthemore
complextheresultingwaveform.Toomuchcomplexity
andthewaveformbecomesnoiseandavoidingthisis
oneofthemostsignificantaspectsofFMtheory.
Therearemanybooksthatcanexplainthe
fundamentalsofFMsynthesisingreaterdetailthan
ispossiblehere.Frequencymodulationhasbeenwidely
usedindigitalsynthesizersthankstothestabilityand
precisetrackingofsoftware-baseddigitalVCOs.The
Z3000’sbuilt-inarithmeticprocessorallowstheuserto
implementtrueFMinanalog,andtobuildharmonically
richsoundsusingacalculatedsynthesisapproach.
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