Điện tử học văn thế minh, 179 trang

"Cuon sach duqc xuat bi'm khuon kh6 Chuang trlnh Dao t #Bp bien cua hai bac 2p+ I > # U dien the hieu dung J 0) 10000 H.32 Ph/in tiell phd Clla m¢t fin hieu hillh l'IIOl1g dOl R2 du~ + - ) - ' +O)OV R3 8000 xllng va I>" ta co: d(2 4000 fo 6000 2000 > plot(U,fO=10000); Tren hlnh 32 ta hru y ding bien dQ cua cac dinh ti It? vai JIn va dQ rQng cua chung tang len to tang (vI i"'j' = Q/'o tang len j() tang) Bien dQ cua dinh dau " I'a cO'tlen hili 166) b~c 4A J2.I n 1I V() "" 0•09 V I'a gta , tf! h"It;U dI:Ing cua , f>IEU CAN GHI NHO • BO LQC DUNG BO KHUECH O{U TiNH TO AN Khi thuc hi~n me)t s6 b() h.lC ta phai Hnh den cac d 19C thOng th:fp d~ khlr lu6n ell thUnh phan hlnh sin noi tren DO chinh la truang h9P eua tin hi¢u lay tu may thu bang FM (di~u tan), tin hi¢u thuang Cht:td mQt th~lllh phtln co tan s6 19 kHz can thiet cha vi¢e rna haa tin hi~u fun I~p th~ (stereo) Ch(rng minh r5.ng b9 19c tren hlnh ve sau day la m(>t bQ 19C thong thap errt m¢t tan s6 Hay xac dinh !fin s6 bi khu va duang ti¢m c~n tan s6 cao (co th~ Slr dyng mQt philn m~m t1nh toan hlnh tMc d~ t1nh ham truY~l1 va ve bieu d6 BODE cua m'.lch) 010 C InF, xac dinh gia trj R d~ co th~ khlr dugc tan s6 19kHz Hay xac djnh bang d6 thi dili thong l'.Ii -3dB xu Hay xac djnh R2 va R wong (rng voi tan s6 d(lc tnmg la 300Hz d6i voi dc gin tr! C = 47nF, Q = ~ (b(> 19C thong th:fp la b(>l9C ki~u BESSEL) Rl c a R12 r~, 12C I I2c 16C/3 R/2 I 6CI5 4* Be} IQc v~n nang b~c Xet b919C nhu tren hlnh ve duoi day: 1) Hay Xilc djnh quan h¢ gifra t:s' t:J ' t:2 va 1:::3' 2) Lam the naa d~ thlfC hi¢n dugc b9 19C thong thap, bQ 19c thong cao, bQ 19C thong dui, b9 19C ch£n dui b5.ng mach tren Neu y nghia cua k 3) Hay bi~u di~n chuc nang cua m vi philn va b9 t6ng C C - t> I-e 00 R r_ _ .0 I R + KDTI3 6* 89 IQc thong thap b~c cae b¢ lqc thong thap b~e vOi h;'lTn truy~n ehuful hoa la liB (jro ) x co the duqe phan Io~i I+J(j-x theo gia tri ella Q nhu sau: • BQ IQe BU1TERWORTH : Bi~u h¢ s6 khueeh d~i eua m~eh da.i thong rat toe; • BQ lQe BESSEL: Di;ie tuyen pha eua b¢ IQe dili thong rat tuyen tfnh (tn~ nh6m Ia h&og so) ; • BQ IQe TCHEBYTCHEEF: Co sl! dao d¢ng vOi bien d¢ £ eua h¢ so khueeh d~i dili thong va co sl! suy gdlm h¢ so khueeh d~i rat nhanh 1) Hay xae dinh gia tr! eua Q eho b¢ IQe BESSEL va BUTTERWORTH tu vi¢e nghien coo cae ham truy~n t~i Ifill e~ x = va Q ella b¢ IQe TCHEBYTCHEEF tuong ling vai s == IdB 2) Ve cae bi6u eho h¢ s6 khueeh d~i va eho pha (tuyen tfnh) tuong ling Tai nguai rat nh~y vai d¢ tuyen tfnh eua pha m¢t tIn hi¢u am ph(re t~p, cae Io~i b¢ IQe nao co th~ duqc sii dl;ll1g eho tin hi¢u am XlSt bQ IQe nhu hinh ve tren, cae b¢ khueeh d~i tfnh toan duqe eoi la If tubng va lam vi¢e ehe d¢ tuyen tmh a) Hay tfnh ti s6 eua cae di¢n the phue: j lli b) Hay xae djnh ham truy~n ella b¢ IQe duai d1;lng tcing quat duqe djnh nghla diU t) va suy cae bi~u tMe eho Go' roO' a va h¢ s6 ehQn Iqc Q 3) BO IQe Heh qrc dung tl:1 chuyen m~eh AB r _ _ _ _ .- - - - - , (I) (2) 7** Vi dl} va cac b9 IQc tich cvc t) Bi~u di8n t6ng quat eua ham truyen eua mpiot(20*log10(subs(R= 1,C=1,p=I*10A x,abs )VsNe)) ),x=-2,,2), _ G(dB) -1 dP 1,5 0,5 x - - - - - - - - - - - log (x) -0,5 - -30 -I,5 40 - 50 2,5 De' kill' 1(111 sf;' 19 kH:, Irfll aolhi fa co X= log 10 -().4 lai hi' \'0 killl{il'h dlli It) -3dB, I/(c Iii rid! lirOng lirO dell 7.6kH: Ball){' thOng 11)(;'p h(je Dtfil'oi h¢ /9C: • BUTTEIiWOf{[}{ , IiIlinil Plla ([Iii 11(> Ire TCIfEBITCIIEPF khong ('() a(! ltIyfil tinh dd! fhong dil ciw, B6/oe TCIfEBtTCItEFF 1'1 fill khall!! a/We 1(IIg dung trollg ki fhudt rilll thallh, Vi dl,1 n/c ht? tich CI!C 1) r==~===, Khi dll! chi hi "lilY db! it nM/a tall cqn thi so' hrplg ell/fa 1'2 p/uii Mllg 0, til 1(/ eo Q = • BESSEL h' Ii f(/ng I'i~c xiiI' dfllh £fJphu thlloe vao S(I Ilw)' dlff (hili eua rosrpkhf x = J j, ;::,-Alg ( (Q(x x) 1) Q r , ) " (l+x~) ~;' fa thu dUf/e: GlI/al Kill Gmax IdB thl III IGol, thbng deii viti f(in sotrung tall/fo, III'" it) ? ~Jt' ~r =2.tildo, x_l"'±2a Cae ughieru co.y IIgh/a hac nol Ilinla: ±u+ (1 I'ut Ii , d" elui[l nll(1II aUf/c 1.1> 0) CLIa phuong lrinh 6wo flf - - ")UJ., 6wo '" ,~,' ",uwo WI Q w() '" ,.~ , 2a) B9 khuedl dui tinh /oiin / dtlf/C 1161 1I/1/! mqt h6 khu(;c'h aai auo viti hi( ,\6' khu{ii.'h dlli ill -/ wIIi/m viijc lrong chi !::B = 0, tuyen linh nell !'A =- r, Dtnh fu(jt 11111 ap d/fng tlli B cho ta: t6n fa! fhi giii Irt lem nllllt eua hi: ,\0' khU!);'h alii !'A 'Cw V.w= 7?+J 1_ : 2Ql =-JOJog ( -f () = / tM mau J(/ ('ua hilu tMc hlnhd nillJ[ vii 1+ va G"lE hi t(li 1'2 X mach itic fa hq x x :r "'-" + Q Q D/plwlo tllY/1I tfnh Illi /on (,\in dieln fa can Q = • TC}{EBITCHEFF: Neil Tql Ddi thon:; 1(1; -3d8, 1/((' /a lai ViJj kiwi Me tai lfin cqll di/1/1 0: Algx '" x - -f I), ~' ,(-1t «p