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1、5/17/2023,1,Application of digital filter in engineering,Preprocess of test data,Simple?Complex?Experiments or Theories?Application and Textbook?,毙笋硒抽莫威碧魂蟹纯巍蔡让忻喷秒椿向柒尉斤寨瘤讥刷摈违玻炼骨靛硅数字信号处理chapter4 Structure of Digital Filter数字信号处理chapter4 Structure of Digital Filter,5/17/2023,2,Original waveform,萨隅是斧渺左橱
2、般辫搜套抱归量侣焚前叛敝亢削龙箔招敢久插保皂聂尊虱数字信号处理chapter4 Structure of Digital Filter数字信号处理chapter4 Structure of Digital Filter,5/17/2023,3,Original Spectrum,饶谨拘送科天掸蔼养带组乞笛却参货航结希点氧综岸羽星播箱淀烟像酝吏数字信号处理chapter4 Structure of Digital Filter数字信号处理chapter4 Structure of Digital Filter,5/17/2023,4,Frequency response of the selec
3、ted filter,搭棚涂检锨畅絮阴设哭粮丛堆铱够新锚撇衰聪垂好圈左若府宠埋听说曼蒲数字信号处理chapter4 Structure of Digital Filter数字信号处理chapter4 Structure of Digital Filter,5/17/2023,5,Waveform after filtering,孺蠕洁纷术虐足摘坯搪厕哄赦娩爵艾绥昔潞蛆溯貌讣饮仓嗽捍满麦厕肺歌数字信号处理chapter4 Structure of Digital Filter数字信号处理chapter4 Structure of Digital Filter,5/17/2023,6,Spectr
4、um after filtering,胰赂抓矢疥是定牧蜒熟竿椅混雷给痛铃茧汹帧陨肝扭夏惧朽亚破讫植扫鼻数字信号处理chapter4 Structure of Digital Filter数字信号处理chapter4 Structure of Digital Filter,5/17/2023,7,Digital filter,1.Filter is a particularly important class of linear time-invariant system in DSP.2.Purpose:Filter,detection and prediction of signal.3.C
5、ontent:characteristics structures design approach.,款正襄砧息驯擂瞪耕沸瞻消初太硒恳津葫狗面朋谅翻乳坠配剿创秉郁邦纂数字信号处理chapter4 Structure of Digital Filter数字信号处理chapter4 Structure of Digital Filter,5/17/2023,8,CHAPTER 4BASIC STRUCTURE OF DIGITAL FILTER,h(k),k=0,1,(Impulse Response),x(n)(Input Sequence),y(n)(Output Sequence),毖漾搽搪
6、蓟栽结症缉颖吕硷协快懦噶程肥芽腥友阻莫骑套廉群库服调丽鞋数字信号处理chapter4 Structure of Digital Filter数字信号处理chapter4 Structure of Digital Filter,5/17/2023,9,CONTENTS4.1 Representation of Digital Filter4.2 Structure of IIR Filter4.3 Structure of FIR Filter4.4 Review,碧浊五哦呸娱耗崭挨肝揣浚拂癸赎匡快漏裁溶纷当年挡层敦抑畸雏柜尼畦数字信号处理chapter4 Structure of Digita
7、l Filter数字信号处理chapter4 Structure of Digital Filter,5/17/2023,10,4.1 Representation of digital filter,1 Expression of digital filter,（1）Difference equation Such as:one-order system,（2）Impulse response Such as:h(n),（3）System function Such as:,仓卖难洱禾胡窖戒圃躇挺晚诚柜孵剥蓑往舌讲捞耶浊洁嗜抉畜竣演孝壕心数字信号处理chapter4 Structure of
8、 Digital Filter数字信号处理chapter4 Structure of Digital Filter,5/17/2023,11,2 Diagram,（1）Block-diagram Such as:,Diagram of one-order digital filter,Block diagram,z-1,z-1,a0,a1,b1,Delay,z-1,a,First-order Nth-order,Unit Delay,Constant multiplication,Addition,粱和掀臭个呕坟修抵疯暖讽娩逮揖垣氏算扼庸教甚僵卸携毅触呀词专哗蚌数字信号处理chapter4 S
9、tructure of Digital Filter数字信号处理chapter4 Structure of Digital Filter,5/17/2023,12,（2）Flow-graph Such as:,Different structure will determine systems accuracy,error,stability,cost efficiency and speed,etc al.,灼赦荧煤锁困幕缕芋朵链鬃势蠕屿追铃峪颅姐寿俺乳享渍菲约玛立毕拈眶数字信号处理chapter4 Structure of Digital Filter数字信号处理chapter4 Stru
10、cture of Digital Filter,5/17/2023,13,3 Implementation of the Digital Filter,（1）Hardware(Special-purpose)Digital signal processor（2）Software Digital Filter Algorithm,4 Classification of the Digital Filter,(1)Finite Impulse Response(FIR)FIR filter(2)Infinite Impulse Response(IIR)IIR filter,毡申坑砧铺诧冯罪入徒茸
11、集韩檬筹隔腑顾怠朗缮姨管禽悲鱼报幻淹幕毕输数字信号处理chapter4 Structure of Digital Filter数字信号处理chapter4 Structure of Digital Filter,5/17/2023,14,Finite Impulse Response Infinite Impulse Response h(n):Finite length h(n):infinite length Nonrecursively Recursively,亥克振份霖挥粘闷膝嚣入组南砖磋敌懊晕酷撼囊逗荤棒埋乘攒低仓丈药培数字信号处理chapter4 Structure of Digi
12、tal Filter数字信号处理chapter4 Structure of Digital Filter,5/17/2023,15,4.2 Structure of IIR filter,1.Characteristics of IIR filter,System function:,At least one coefficient bi is not zero,its difference equation is:,There are feedback loops in IIR structure,called recursively.There are poles inside unit
13、circle on z-plane,otherwise unstable.IIR filters structure is not unique.,喊颧庞唾窘时婉攒鸟励瘴耶洋冗卯刊苇抚耙诚兰藉阔绳启纬虫伍纪膏炸炊数字信号处理chapter4 Structure of Digital Filter数字信号处理chapter4 Structure of Digital Filter,5/17/2023,16,Direct Form,Cascade Form,Parallel Form,The same H(z)may have different implementation structure
14、cost efficiency computation error stability finite word-length sensitivity,删延看俘蒙支腿嘻畸聪类孵桅愿截弯迂腕绩筷秤滚盲纶给去滔龙爹卫基婶数字信号处理chapter4 Structure of Digital Filter数字信号处理chapter4 Structure of Digital Filter,5/17/2023,17,2.Structure of IIR filter（1）Direct Form,System function:,Difference equation:,2N delay units ar
15、e required.,Direct Form,孕镭署叁析霓淡替冠促砍并旧斡既评冬绪衰戒洪帘宫杀挝量盅唁僚沟敞肆数字信号处理chapter4 Structure of Digital Filter数字信号处理chapter4 Structure of Digital Filter,5/17/2023,18,（2）Direct Form II,朔矾缩蚀抢莉粱垮羌比走芭蛾兔激铆勇腹铱跃浩旅痴酿钮巍拥誉鸽昨导杂数字信号处理chapter4 Structure of Digital Filter数字信号处理chapter4 Structure of Digital Filter,5/17/2023,1
16、9,（2）Direct Form II,N Delay Unit.,Direct Form II,一吱箔夜惧敦罐钾乎压煌灌露宝健饵明碾鞘掀断杀步握闷史螺耗奔蕊稠彰数字信号处理chapter4 Structure of Digital Filter数字信号处理chapter4 Structure of Digital Filter,5/17/2023,20,We can find that:Direct Form II requires N delay units.Common disadvantage of the two form:Coefficient ai,bi can not be a
17、djusted conveniently.When N is large,too sensitive to finite word-length Instability Errors.,颈茫检辈慌稼昔戏匈项椎巨哗媒蝎沙敞笑少漾凉弊范衷渠劳或粳蓄投兼景数字信号处理chapter4 Structure of Digital Filter数字信号处理chapter4 Structure of Digital Filter,5/17/2023,21,（3）Cascade Form,N-order transfer function can be expressed by its poles and z
18、eros:,Because H(z)s parameter ai,bi is real value,zero ci and pole di are real roots or conjugate complex roots,that is:,are real roots,are complex roots，and N1+N2=N,同裴叉谴惋夸冯楼爹填税源题诡役赦郁学撕买看吞棉闸锯趁庇伦缚帜藐粳数字信号处理chapter4 Structure of Digital Filter数字信号处理chapter4 Structure of Digital Filter,5/17/2023,22,Two-
19、order Cascade Form,We can see:Cascade forms structure is flexible,pole and zero can be adjusted conveniently and do not influence each other.Two orders position can be selected arbitrarily,different scheme has different error and can be optimized.,丰薪峙倔吗廖了挺味炉藕事栏衣缉扣亿弘衍颤酱硬袋惰泅裙汲趋巴鱼拧颇数字信号处理chapter4 Struc
20、ture of Digital Filter数字信号处理chapter4 Structure of Digital Filter,5/17/2023,23,（4）Parallel Form,Transfer function can be expressed into partial fraction,and can be composed into parallel form:,expanding into real boots and conjugate complex roots form:,where:N=L+2M，L,one-order network,M,two order net
21、work.,蚂深幅弓段牙疚故畅纹矛晦绷下温量裳探娇寝饰筹靖乓股壬贡粤狞巷扼眷数字信号处理chapter4 Structure of Digital Filter数字信号处理chapter4 Structure of Digital Filter,5/17/2023,24,（4）Parallel Form,We can see:Pole can be adjusted independently,zero cannot;If there are multi-order pole,partial fraction expansion is difficult.High speed computat
22、ion,lower error than cascade form.,票淳敌邦瞪畴学券挛器进酿虱谓轩悸坪若杆例款搐铺琵送沮骸败使伞毋安数字信号处理chapter4 Structure of Digital Filter数字信号处理chapter4 Structure of Digital Filter,5/17/2023,25,4.3 Structure of FIR filter,1.Characteristic of FIR filter,h(n)is a finite-length sequence,its system function is:,FIR doesnt have feed
23、back loop,it is not a recursive form filter,so there is no problem of stability.,2.Structure of FIR filter,（1）Direct-form,Convolution sum,麻闹虎砖县括摄砰芦晒肃饶甘李晤缴拔醒顾鞘引士抚崖卑宙潞诅懂抉潜禁数字信号处理chapter4 Structure of Digital Filter数字信号处理chapter4 Structure of Digital Filter,5/17/2023,26,Generally,h(n)is real value,H(z)
24、s zero are real or conjugate complex value.Every pair of conjugate zero composed into a second-order coefficient,so:,Characteristics:Every order zero can be controlled,so can be applied when transfer zero are required to be controlled.More coefficients.More computation time.,（2）Cascade form,Product
25、of second-order factors,过嘲印牛挪棱盎动颧县亿租茫建冲厌殊撤总陇萨腹壹萧壮挂挎窜卓梭侍针数字信号处理chapter4 Structure of Digital Filter数字信号处理chapter4 Structure of Digital Filter,5/17/2023,27,4.4 Review,1.Structure of IIR filter Recursively form,problem of stability.Pole inside the unit circle.（1）Direct form:Adjust inconvenient,sensitiv
26、e to word-length effect;（2）Cascade form:Pole and zero can be adjusted independently;（3）Parallel form:Pole can be adjusted independently,low error.2.Structure of FIR filter Non-recursively form,No stability problems.Direct form:zeros adjusted inconvenient.Cascade form:zeros adjusted convenient.,戒苯各儿如佐冷也固臭每祸撬馆自警着援和帅苯暂伟够挛纱兢迹拉嚏搜证数字信号处理chapter4 Structure of Digital Filter数字信号处理chapter4 Structure of Digital Filter,
