-數(shù)字信號(hào)處理緒論課件

DigitalSignalProcessing

Introduction工程技術(shù)研究中心外網(wǎng)郵箱:內(nèi)網(wǎng)郵箱：什么是數(shù)字信號(hào)？what數(shù)字信號(hào)是時(shí)間離散，幅度也離散的信號(hào)Digitalsignalisbothdiscreteintimeanddiscreteinvalues.2什么是信號(hào)處理？what信號(hào)處理包括：分析信號(hào)組成：譜分析詮釋信號(hào)特性：根據(jù)分析數(shù)據(jù)理解信號(hào)操控信號(hào)：調(diào)制技術(shù)從有利于傳輸?shù)慕嵌热ジ淖冃盘?hào)濾波技術(shù)提取信號(hào)有用信息Signalprocessingistheanalysis,interpretationandmanipulationofsignals.3為什么進(jìn)行A/D變換數(shù)字處理器無(wú)法處理和識(shí)別模擬信號(hào)，二者之間必需有一個(gè)翻譯中介接口，這個(gè)接口稱為模數(shù)轉(zhuǎn)換器。輸出的數(shù)字信號(hào)進(jìn)行進(jìn)一步的數(shù)字處理。Thereisaneedforaninterfacebetweentheanalogsignalandthedigitalprocessor.Thisinterfaceiscalledananalog-to-digital(A/D)converter.TheoutputoftheA/Dconverterisadigitalsignalthatisappropriateasaninputtothedigitalprocessor.5為什么進(jìn)行D/A變換實(shí)際應(yīng)用中有些是做數(shù)據(jù)分析，只要分析出模擬信號(hào)中的信息成分即可，這時(shí)候數(shù)模轉(zhuǎn)換就不必要了However,thereareotherpracticalappsinvolvingsignalanalysis,wherethedesiredinformationisconveyedindigitalformandnoD/Aconverterisrequired.

現(xiàn)實(shí)生活中看到、聽(tīng)到、感覺(jué)到，自然生成的信號(hào)一般為模擬信號(hào)，那么經(jīng)過(guò)數(shù)字處理的輸出信號(hào)在需要的時(shí)候也要有一個(gè)中介接口，即數(shù)模轉(zhuǎn)換器，恢復(fù)對(duì)應(yīng)的模擬信號(hào)輸出。如雷達(dá)信號(hào)分析，只需要獲取飛機(jī)的位置和飛行速度信息，沒(méi)有必要再進(jìn)行數(shù)模轉(zhuǎn)換。Forexample,inthedigitalprocessingofradarsignals,theinformationextractedfromtheradarsignal,suchasthepositionoftheaircraftanditsspeed,maysimplyprintedonpaper.ThereisnoneedforaD/Aconverterinthiscase.6數(shù)字信號(hào)處理的不足系統(tǒng)復(fù)雜度相對(duì)高

Increasedsystemcomplexity可處理頻率范圍有限（10MHz字長(zhǎng)12～16bits）Limitedrangeoffrequencies功耗相對(duì)大Consumeelectricalpower7為什么選擇數(shù)字信號(hào)處理？why可及模擬系統(tǒng)之所不能、抗干擾能力強(qiáng)Lesssensitivetotolerancesofcomponentvalues模擬系統(tǒng)信號(hào)容易受干擾，產(chǎn)生失真；二進(jìn)制的數(shù)字信號(hào)在傳輸、存儲(chǔ)、處理中不容易丟失信息。便于大規(guī)模集成EasilyintegratedinVLSI(VeryLargeScaleIntegrated)circuits

9為什么選擇數(shù)字信號(hào)處理？why數(shù)字信號(hào)處理的優(yōu)點(diǎn)是喜聞樂(lè)見(jiàn)，不足在實(shí)際應(yīng)用中影響并不大Theadvantagesfaroutweighthedisadvantagesinvariousapps隨著DSP硬件價(jià)格的下降，未來(lái)的電子行業(yè)很快會(huì)被DSP占領(lǐng)，學(xué)好DSP的重要性日益凸現(xiàn)Withthecontinuingdecreaseinthecostofdigitalprocessorhardware,thefutureofelectronicsisDSP，andwiththisbookyouwillnotbeleftbehind數(shù)字信號(hào)處理廣泛應(yīng)用于語(yǔ)音信號(hào)處理，電話信道中的信號(hào)傳輸、圖像處理和傳輸，地震學(xué)、地質(zhì)學(xué)、石油勘探、核爆炸檢測(cè)以及外太空信號(hào)處理Dsphasbeenappliedinspeechprocessing,signaltransmissionontelephonechannels,imageprocessingandtransmission,seismologyandgeophysics,oilexploration,thedetectionofnuclearexplosions,theprocessingofsignalsreceivedfromouterspace10數(shù)字信號(hào)處理能否解決所有問(wèn)題？當(dāng)數(shù)字電路處理速度能夠滿足需求時(shí)，DSP技術(shù)仍然是首選項(xiàng)。wheredigitalcircuitsareavailableandhavesufficientspeedtoperformthesignalprocessing,theyareusuallypreferable.DSP不能解決所有信號(hào)處理問(wèn)題，當(dāng)信號(hào)帶寬極其寬，有實(shí)時(shí)處理需求，可能就只能借助模擬或者光信號(hào)處理技術(shù)了。DSPisnotthepropersolutionforallsignalprocessingproblems.Indeed,formanysignalswithextremelywidebandwidths,real-timeprocessingisarequirement.Forsuchsignals,analogor,perhaps,opticalsignalprocessingistheonlypossiblesolution.11沒(méi)有復(fù)雜的數(shù)學(xué)推導(dǎo)證明，重要的是理解，而非單純證明公式的正確性nomathematicalmiracles避免不加解釋直接給出結(jié)論noconclusionssuchas:“itisobviousthat”首先學(xué)會(huì)基本規(guī)則和步驟，然后組合運(yùn)用實(shí)踐Firstwelearnthefundamentalrulesandprocesses,andthenpracticeusingthemincombination.知識(shí)點(diǎn)講解通過(guò)解釋加詳細(xì)例證的方式，確保理解和掌握Thisbook'sgoalistogentlyprovideexplanationfollowedbyillustration,notsothatyoumayunderstandthematerial,butthatyoumustunderstandthematerial為什么數(shù)字信號(hào)處理的學(xué)習(xí)很容易？why13數(shù)字信號(hào)處理理論概覽14數(shù)字信號(hào)處理課程內(nèi)容Contents1.離散序列和系統(tǒng)Discretesequencesandsystems2.周期采樣Periodicsampling3.離散傅立葉變換TheDiscreteFourierTransform4.快速傅立葉變換TheFastFourierTransform5.有限沖激響應(yīng)濾波器FiniteImpulseResponsefilters6.無(wú)限沖激響應(yīng)濾波器InfiniteImpulseResponsefilters7.特殊的低通FIR濾波器SpecializedlowpassFIRfilters8.正交信號(hào)Quadraturesignals9.離散希爾伯特變換ThediscreteHilberttransform10.采樣率變換Samplerateconversion11.信號(hào)平均Signalaveraging