1、12s(t)Analog signal3)()()()(kTsttstsTk)()()(ffSfSknsnffTf)(1)(41()()snffnfT()()()kSfS ff11()()()()kssnSfS ffnfS fnfTT52sHff67)1(222nkBnkBBfs3BB2B4B5B6BfL0fs8（a）Baseband signal(b)PAM signal (c)PDM signal(d)PPMsignalFigure 4.2.6 Analog pulse modulation9图4.3.1 抽样信号的量化1(),when()qiiiskTqms kTm10Mabv/)(vi
2、amiMimmqiii,.,2,1,2111baMimmkkikkkqkqkqiidssfqsdssfssssEN12221)()()()()(viami2vviaqibakkkkdssfssES)()(2212avMvadsavviasdsaqsdssfqsNMiMiviaviakkMimmkikMimmkkikqiiii24122121)2(21)()()(3121)1(2121211 avM22/12qNv aakkvMdsasS222)(12212MNSq20lg(dB)qdBSMN13ydxdyxyydydxx14Ny1dydxNydydxx115dydxNydydxx1xNdydx
3、ckyxlnkkyxln1ln/yx k1611,ln1ln110,ln1xAAAxAxAAxy1718191ln1lnxy25512255125625512568/iiyx20212223Figure 4.4.1 Principles of PCM7654321345676011 100 101 110 111 1103.153.965.006.386.806.42Binary symbolSampledvalueQuantizedvaluePractical value of signalQuantized value ofsignalQuantization error24PCMsign
4、alSampleandholdcircuitEncoderAnalogsignalinputQuanti-zerEncoderDecoderAnalogsignaloutputDecoderLowpassfilter252627)2(B/fH2 Nq/S2829kkkkkkkkksssssesrs*piikiksas1*AdderSamplerQuantizerPredictorEncoding30s*krkPredictorDecoding31kkkkkkkkkrersesssq)(*2(1),(1)2MvvM+-v v0 vM1M2M3M4图图4.5.2 ,和和M之间关系之间关系vqfk1
5、)(322/2/222/2/2212)(1)()(vvkkvvkkkkvdqqvdqqfqqEssqffNfvfP0,12)()(2 sLLqqffNvffPN12)(233tAtm0sin)(tAdttdm00cos)(sfTA/00max/sfA2022220222max822fffASss342022220222max822fffASssvM2)1(20222220222232)1(821ffvMffvMSssLsqfffMNNS203228)1(33536sk*Sampling2 level quantizations(t)skekrkskdelayrksk*(a)Encoder (b
6、)Decoderdelay37(a)Encoder(b)DecoderIntegratorSampling&decisions(t)e(t)d(t)s(t)Integratord(t)Low-passT(t)s(t)Output binarywaveform38Output binarywaveformIntegratord(t)Low-passs(t)(b)Decoder3940(a)Basic quantization noise(b)Overload quantization noise noise41sfTk/4243()1/2,f ee 321)()(2222deedeefeteEs
7、sffffP0,3)(2sLLqffffPN3)(244tAts0sin)(00()/cosds tdtAt0A/sTf max0/sAf2022220222maxmax822fffASssLsLssqfffffffNS2032220222max8338p 经常不断地学习,你就什么都知道。你知道得越多,你就越有力量p Study Constantly,And You Will Know Everything.The More You Know,The More Powerful You Will Be写在最后感谢聆听不足之处请大家批评指导Please Criticize And Guide The Shortcomings结束语讲师：XXXXXX XX年XX月XX日
