數(shù)字通信原理實(shí)驗(yàn)報(bào)告

1、數(shù)字通信原理實(shí)驗(yàn)報(bào)告學(xué)院:班級(jí):姓名:學(xué)號(hào):指導(dǎo)老師:日期:xx學(xué)院xxxxxxxxxxxxxxxxxx2017.7.10一. 目錄一. 目錄2二. 實(shí)驗(yàn)?zāi)康募霸?1. 方波信號(hào)32. fm、pm角度調(diào)制3三. 實(shí)驗(yàn)過(guò)程41鋸齒波信號(hào)42. fm/pm角度調(diào)制5a . fm頻率調(diào)制5b .pm相位調(diào)制8c.貝塞爾函數(shù)敲寫(xiě)代碼如下： 83. 取樣及取樣定理9四. 實(shí)驗(yàn)結(jié)果131. 鋸齒波信號(hào)的時(shí)域圖132. 鋸齒波信號(hào)的頻域圖133. 頻帶頻率調(diào)制后調(diào)制信號(hào)的頻域圖144. 頻帶頻率調(diào)制后調(diào)制信號(hào)的時(shí)域圖145. 頻帶相位調(diào)制信號(hào)的吋域圖156. 頻帶相位調(diào)制信號(hào)的頻域圖157連續(xù)、離散正弦波

2、及脈沖信號(hào)波形的示波器顯示圖16&連續(xù)、離散鋸齒波及采樣脈沖信號(hào)波形的示波器顯示圖169. 離散鋸齒波信號(hào)頻譜顯示圖1610. 0到4階的貝塞爾函數(shù)圖像：17五. 實(shí)驗(yàn)總結(jié)18二. 實(shí)驗(yàn)?zāi)康募霸韺?shí)驗(yàn)?zāi)康模和ㄟ^(guò)在matlab上做一些仿真實(shí)驗(yàn)使得自己能夠更好的了解數(shù)字通信原理這一課程。實(shí) 驗(yàn)結(jié)朿后能夠更加地熟練使用matlabo 實(shí)驗(yàn)原理：1. 方波信號(hào)周期信號(hào)是指每隔固定的時(shí)間間隔，周而攵始重現(xiàn)的信號(hào)，可表示為：x(t)=x(t+nt). 鋸齒波信號(hào)由重復(fù)序列模塊產(chǎn)生。該模塊輸出一個(gè)預(yù)先確定波形的標(biāo)量信號(hào)，使用模塊的吋 間值和輸出值這兩個(gè)參數(shù)值，更可以得到任意的鋸齒波波形。2. fm、

3、pm角度調(diào)制fm頻率調(diào)制：頻率頻帶調(diào)制器的載波(一般是正弦波)的頻率與輸入信號(hào)的幅度成正 比。頻帶頻率調(diào)制器對(duì)輸入的實(shí)信號(hào)實(shí)施頻率調(diào)制，產(chǎn)生抽樣形式的調(diào)制信號(hào)。假設(shè)輸入的 實(shí)信號(hào)實(shí)施頻率調(diào)制，產(chǎn)生抽樣形式的調(diào)制信號(hào)。fm從輸入的基帶平率調(diào)制信號(hào)中解調(diào)出 原始的信息序列。頻帶頻率解調(diào)器的輸入信號(hào)是抽樣形式的標(biāo)量信號(hào)，輸入信號(hào)是1維的標(biāo) 量信號(hào)。基帶頻率解調(diào)器使用了低通濾波器，這個(gè)低通濾波器由參數(shù)lowpass filter nu merator 和 lowpass f ilterde nomin at or 確定。pm相位調(diào)制：頻帶相位解調(diào)器對(duì)輸入的頻帶相位調(diào)制信號(hào)中解調(diào)出原始的信息序列。 它的

4、輸入信號(hào)和輸出信號(hào)都是實(shí)數(shù)形式的抽樣信號(hào)，頻帶相位解調(diào)中的壓控振蕩器的靈敏度 由參數(shù)vco gain確定。貝塞爾函數(shù)：調(diào)頻信號(hào)的頻譜中包含有多個(gè)分量，因?yàn)槔碚撋险{(diào)頻信號(hào)的頻帶寬度為無(wú) 線寬，但是，實(shí)際上頻譜的分布認(rèn)識(shí)相對(duì)集中的。只要適當(dāng)?shù)倪x擇n值，當(dāng)邊帶頻率分量小 到一定程度時(shí)便可以忽略不計(jì)。3. 取樣及取樣定律在數(shù)字通信系統(tǒng)屮傳輸模擬信號(hào)，首先要完成模數(shù)變換。發(fā)送端現(xiàn)將模擬信號(hào)取樣， 使其成為一系列離散的取樣值，然后再將取樣值量化為有限的量化值，并經(jīng)編碼變化成數(shù)字 信號(hào)用數(shù)字通信方式傳輸。在接收端，則把接收到的數(shù)字信號(hào)恢復(fù)成模擬信號(hào)。顯然，采樣 頻率越高，量化級(jí)越多，越能表現(xiàn)信號(hào)的細(xì)節(jié)，代價(jià)

5、是模數(shù)轉(zhuǎn)化變得越復(fù)雜。傳輸代價(jià)就越 大。取樣定律告訴我們：如果對(duì)某一帶寬有限的時(shí)間連續(xù)信號(hào)進(jìn)行采樣，且采樣速率達(dá)到兩 倍以上的最高工作頻率，那么根據(jù)這些抽樣值就能還原出原始的信號(hào)。三. 實(shí)驗(yàn)過(guò)程1 鋸齒波信號(hào)首先搭建如圖所示的電路，然后再調(diào)試信號(hào)repeating sequencezero-orderzero-orderholdhold block parameters: repeating sequeneer«p«atins table (sask) (link)output a r«p«ating s«qu«nc« of

6、 nusbtrs specified in a table of tis*-valut pairs values of tise should b« sonotonically inertasinf.partx«t«rstize values:output values:qkctnctlm«lpapplyk block parameters: zero-order holdr -ztro-order holdzero-order hold.sazplt tist j： for inherited):x). 1? x block parameters: s

7、pectrum scopespectrus scop«and display tht periodofraz of each input siml based inputs to the block should use th« buffering option.scop. propertits | display properties | kxis propertits | line 4 | faractttri! buffer input3uff«r size: |1293uffer overlap: |64! specify ff7 itnfthfft le

8、nrth: |256£usbr of spectral average!： |2apply2. fm/pm角度調(diào)制首先先搭建如圖所示的電路，并且調(diào)試各個(gè)電路參數(shù) afm頻率調(diào)制modulator passbandsiffnal generatoroutput various ravt forxi:y(t> acp»tbvtfors(frto t)araxeters<avt fors:ti®* (t): |ui7iibulation t:s«asplitud:ffrtqutncr：units: | hertzp interpret vector

9、 parastttrs as adi applyblock parameters: fm modulator passbandfm modulator passband sask) (linkmodulate the input signal usin* th« fr«qu«ncy sodulation s«thod. tht input sirnal suit b« a sa=pl«-bas«d scalar tht output is 1d scalar parumterscarrier frtautncy (hx):p

10、h“("d：|o-modulation constant 'h«rtz ptr volt):sg： tis« (s):syabol interval use inf for analof eod>:巳 block parameters: zero-order hold? xz«ro-ordtr holdztro-ordtr hold.sazpl« t£z« (-1 for £nh«rit«d' :|2vtqk | cuc.l |加 ply| block parameters

11、: spectrum scopesp«ctrus scopecooputt and display the ptriodotras of «ach input :.non-frast bas«d inputs to tht block should use tht bufftrinc option.scope proptrtiesj | displty properties | axis propertits | lint )| para=«t«rsr/ bufftr inputbuffer six: |1024buffer overlap:

12、|256f/ specify fft l«n<thfft l«nrth: 11024xuabtr of spectral av«ra(«s: |10| ctnc.l | h.lp | &pply |b .pm相位調(diào)制block parameters: pm modulator passband( x* mcdulator passband (aask) (link) iodulatt th« input iifnal us:nc th« phai« s&dulation stthod. the inpu

13、t iifnal suit b« sasplt-bastd scalar. th. output is a 1-d scalar.mascarrier fr«qu«ncy (hz):initial phase (rad):i5modulation constant (radians p«r volt):interval use inf for analot cast):qkqtnctlm<lpapply |c.貝塞爾函數(shù)敲寫(xiě)代碼如下：x-(0:0. 02:14:y0=besseli(0, (i*x),1);z0»real(yo): yl&

14、#171;besseli(1, (i*x),1):zlbreal(yl/i);y2«besseli(2, (i*x), 1):z2»real(y2/-l):y3»besseli(3,(i*x),1)：z3«real(y3/-i): y4=besseli(4,(i*x),1)：z4-real(y4): plot (x, zo, * k*,x, zl, * rf, x, z2,' b' ,x, z3, * m*, x, z4, g )： grid3.取樣及取樣定理模擬信號(hào)仿真電路方框圖如下:corxmnf調(diào)試參數(shù)過(guò)程如下:盤 block pa

15、rameters: sine wave? xsin* <avtouiut a sin« vavt：0(t> - asp<s:n(2<pi»frtq<t-phait) biassir.td«t«rsin<s th« cocputational ttchnxqut used. th p<ras«t<rs in the twotypes art related throufh:sasplts per period 2>pi / (freoutncy saspl* t:se)nusbtr

16、of offset sasplts phait s&zplts per ptriod / i2<pi>us# the lasplebaied lint type if nuserical problesi due to runninf for larc< tims ( ovtrflov in absolute tint) occurparaottrssint type:u“ sizulationg (t>:asblitud:fbd：frtqutncy (xad/sec):|2iphase (rad): |osmp1|ofz interpret vector pa

17、rastters as 1-dqk block parameters: pulse generatorc«n«ratoroutputif t >- phaitdlay _puli« is on y!t) azpl:tud«»ls«y(t) 0ndfalse typ< d«ttrsin«s th« ccsputational t»chnxque us»d.zjzlt：c<-bai<d is yco=ndd for ut< ith a variable ste

18、p lolvtr rhilt sbzpl*bas»d ii rxoce«ndd for us« with fixed step solv«r or <ithin discr«t« portion of a sod«l usini a variabl* st«p iolv«rfulse typ:(t): |ub« sieulatxon t:s« splitud:fhast delay (s»cs):feriod (secs):|57o25pulse width (% of

19、 period): fio4 block parameters: constant? xconstantoutput th« constant fpacified by the e constant %ealu«" paxaz«t«r. ifconstant value' is a vector and interpret vector parar«ters as1-dj £s on, treat the constant value as a 1-d array. otherrist output a matrix

20、 with th« s&ze distnsions as the constant valu pltinj | signal data types |constant valu:|2 0 -3. 3f? interpret vector paraz«t«rs as 1-dsusplt tia:| infholdspeorum scop*rtptatinf table (cask) (link)output a r«p<atin( s*qu«nc« of nusb«rs specified in a tabl&#

21、171; of tizt-valut pairs values of tis« should b« s»noton:call7 incrttsing.pax&£«t»rstis« values:output values:roti yc | £tnc«l |apply bbck parameters: pulse generatcrpultt ctntratoroutput j>u!b«s:if (t >y(t)- elsey(t) ndfhas«d«la

22、y)ii onazplitud*full, type d“rain” th« eosputatiotial txhniw used.tist-based xs r«coaeend«d for uie with a var:abl« it«p sol*巧 vhilt s&2dl<*bai>d ii re:o««nded for use ith a fixed it«p solver or ithin dikx«t< oortion of a od: usinc a variable

23、 step solver.parmmterspu：“ type kffm(t>: |uit siculatioc txz#agplitud:|51period(0.525pu：“ width (0 of d"iod):ph»(>):|3& inttrprtt vector p&xastters as 1-dm<lpapply?x elock parameters: zero-order holdl spectrus scopecosputt and display the ptriodovras of tach input sxrnal.

24、nonfras« baitd inputs to th« block should use th* buff«rinf option.| kxis propertiessopt proptrtits. i display propertiesp&ras«t«rir buffer inputbufftr size: |512buffer overlap: |256p specify fft ltnfthfft lenrth: il2xusber of spectral av«ra(«s: 4okctnctlapply |四. 實(shí)驗(yàn)結(jié)果1鋸齒波信號(hào)的吋域圖雪自asm© a 垢me offset 02 鋸