PIC16C74数字信号处理

Thisapplicationnotedescribesthebasicissuesthat

needtobeaddressedinordertoimplementdigitalsig-

nalprocessingsystemsusingthePIC16C74and

providesapplicationcodemodulesandexamplesfor

DTMFtonegeneration,a60Hznotchfilter,anda

simplePIDcompensatorforcontrolsystems.These

routinescanalsobeusedwithotherPIC16C6Xand

PIC16C7XXXprocessorswithminormodificationsand

theadditionofexternalanalogI/Odevices.

Theuseofgeneralpurposemicrocontrollersfor

low-enddigitalsignalprocessingapplicationshas

becomemorecommonplacethesedayswiththeavail-

abilityofhigherspeedprocessors.Sincemostsignal

processingsystemsconsistofahostprocessorand

dedicatedDSPchip,theuseofasinglemicrocontroller

toperformboththesefunctionsprovidesasimplerand

lowercostsolution.Inaddition,thesinglechipdesign

willconsumelesspowerwhichisidealforbattery

poweredapplications.ThePIC16C74withitson-chip

A/D,PWMmodule,andfastCPUisanidealcandidate

foruseintheselow-bandwidthsignalprocessing

applications.

AtypicalsignalprocessingsystemincludesanA/D

converter,D/Aconverter,andCPUthatperformsthe

signalprocessingalgorithmasshowninFigure1.AN616DigitalSignalProcessingwiththePIC16C74Theinputsignal,x(t),isrstpassedthroughaninputAuthor:DariusMostowlter(commonlycalledtheanti-aliasinglter)whoseDesignConsultantfunctionistobandlimitthesignaltobelowtheNyquistrate(onehalfthesamplingfrequency)topreventaliasing.ThesignalisthendigitizedbytheA/DINTRODUCTION