ch1 - GII THIU V DSP Khi nim H thng x l tn hiu s tng t S...

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Unformatted text preview: GII THIU V DSP Khi nim H thng x l tn hiu s tng t S hnh thnh & pht trin ca DSP s khc nhau gia DSP & P Lnh vc ng dng DSP Thun v Bt li ca DSP ThS. Trn Thanh Tng KHI NIM Tn hiu l biu din vt l ca thng tin Tn hiu c biu din bng hm ton hc Sa(t) = f(t) ia(x,y) = f(x,y) ia(x0 ,y0 ) t x0 ThS. Trn Thanh Tng y0 y x KHI NIM Tn hiu lin tc: bin c lp lin tc Tn hiu tng t: tn hiu lin tc c hm lin tc Tn hiu lng t ha: tn hiu lin tc c hm ri rc xa(t) xa(t) 5V 4V 3V 2V 1V ThS. Trn Thanh Tng t t KHI NIM Tn hiu ri rc: bin c lp rc Tn hiu ly mu: tn hiu ri rc c hm lin tc Tn hiu s: tn hiu ri rc c hm ri rc xs (nTs) xd (nTs) nTs ThS. Trn Thanh Tng nTs H THNG X L TN HIU xa(t) H THNG TNG T ya(t) xd(t) H THNG S yd(t ) xa(t) ADC xd(t) H THNG S yd(t) DAC yd(t) ThS. Trn Thanh Tng X L S TN HIU TNG T xa(t) H thng DSP khc t B x l s t xa(t) Mch lc A/D D/A Mch lc x|a(t) x(n) 101 100 011 010 001 000 101 y(n) My tnh 100 111 010 001 000 ThS. Trn Thanh Tng t t BIN I A/D A/D Tn hiu tng t Ly mu & Gi Lng t & M ha Tn hiu s Tn hiu lin tc Ly mu v gi Tn hiu tng t Tn hiu tng t x(n)=xa(nTs) Gi Mu bc thang Fs = 1/Ts ThS. Trn Thanh Tng LNG T HA & M HA Lng t ha: Mi mu c gn mt gi tr trong tp hp gi tr ri rc (mc lg. t) M ha: Mt gi tr ri rc trn tng ng vi mt t m nh phn m bit Gi tr ri rc thuc khang (Xmin,Xmax) Lng t v m ha u Lng t v m ha u: Mc lg. t cch u v cng chiu di t m Lng t v m ha khng u: Mc lg. t khng cch u v khng cng chiu di t m ThS. Trn Thanh Tng LNG T & M HA IU Bc lg. t ha = X max - X min X max - X min X max - X min = n -1 2m - 1 2m Tn hiu lng t Sai s lg. t ha e(n) = x(n) Tn hiu ri rc trc khi lng t xq(n) - Sai s lg. t trung bnh < e< 2 2 /2 1 e= ede = 0 - / 2 ThS. Trn Thanh Tng LNG T & M HA U 4 3 2 1 Tn hiu tng t 2Ts 3Ts 4Ts 5Ts 1Ts 6Ts 7Ts 8Ts Xmax -1 0 -2 -3 -4 Xmin ThS. Trn Thanh Tng NHIU LNG T Sai s lg. t c gi tr ngu nhin (-/2 , /2 ) nn c gi l nhiu lng t Cng sut trung bnh v hiu dng ca nhiu lg.t e2 = 1 2 e 2 de = 12 - / 2 /2 erms = e 2 = M hnh ha b lng t x(n) B lng t ha e(n) xq (n) 12 T s tn hiu trn nhiu lng t X - X min m SQNR = 20 log10 max 20 log10 (2 ) = 20m log(2) = 6m (dB) ThS. Trn Thanh Tng LNG T & M HA KHNG U Khang cch gia cc mc lg. t khng u Chiu di t m khc nhau Nhiu mc lg. t cho bin d nh & t mc lg. t cho bin ln Bc lng t Mc tn hiu vo Nn tn hiu c bin ln trc khi qua b lg. t v m ha u ThS. Trn Thanh Tng COMPANDING c tuyn vo ra ca b nn law: Hoa k ,Nht Bn A law: Chu u ThS. Trn Thanh Tng BIN I D/A Bin i tn hiu s sang tn hiu tng t Ni suy cc mu tn hiu Ni suy tuyn tnh Ni suy bc hai ........... Tn hiu c bng tn hu hn, s c mt hnh thc ni suy ti u ThS. Trn Thanh Tng ALIASING Alias: hai tn hiu sin ri rc F1 v F2=(F1+kFs) khng th phc hi li tn hiu lin tc ThS. Trn Thanh Tng NH L LY MU Tn s ly mu bao nhiu ? Tn s ly mu (Fs) 2*Tn s cc i (Fmax) Tn hiu tng t xa(t) c th phc hi bng cc dung hm ni suy g(t) g (t ) = sin 2Fmax t 2Fmax t x a (t ) = n = - x(n) g (t - F ) s ThS. Trn Thanh Tng n NH L LY MU Nu Fs = 2Fmax (Tn s Nyquist) x a (t ) = n = - x ( n) sin 2Fmax (t - n / 2 Fmax ) 2Fmax (t - n / 2 Fmax ) ThS. Trn Thanh Tng HNH THNH & PHT TRIN DSP Th h (I) 1979-1985 1979(II) 1985-1988 1985(III) 1988-1992 1988(IV) 1992-1997 1992(v) 1997 c trng ca kin trc tr Kin trc Harvard B nhn bng mch in t Thc hin ng thi, S bus thi, tng, B nh trn chip ng, Php tan s thc trn chip a x l, chuyn x l nh v l, x l m thanh, t tn nng lg. thanh, Tch hp mt cao Chip NECPD772, Intel 2920, NEC Bell Labs DSP1, Texas instruments TMS320C10 TMS320C25, MC56001,DSP16(AT&T) TMS320C30, MC96002,DSP32(AT&T) TMS320C40, 50 TMS320C80 TMS320C6x,Philips TriMedia,Motorola Starcore ThS. Trn Thanh Tng DSP & P DSP x l tn hiu thi gian thc DSP khng OS, Cache, single task DSP c kin trc Harvard DSP thc hin MAC trong 1clock Chng trnh lu trong B nh tc cao' Chng cao' Lp trnh bng hp ng rng Bus nh ROM & RAM trn chip DSP thc hin cc php tnh so thc Khng c ADC & DAC Chun so snh: FIR/IIR, FFT, tch chp, du chm ng snh: chp, ThS. Trn Thanh Tng NG DNG CA DSP X l nh: nhn dng, chnh sa,... o lng & iu khin: phn tch ph, iu khin tc & v tr, ... m thanh:nhn dng m thanh, tng hp m thanh,... Qun s: x l radar, hng dn tn la, truyn tin,... Vin thng: trit ting di, tri ph,... Y hc: chun on bnh nhn, phn tch ECG, lu tr nh X quang,... Khng gian: x l nh khng gian, nn d liu, phn tch cm bin bng u thu khng gian t xa,... ThS. Trn Thanh Tng THUN & BT LI CA DSP Thun li Bt li chnh xc c m bo Cht lng sao chp tt Cht lng khng thay i theo t0 v tui th Mm do cao Mt s thng tin dng s Tc v gi thnh S lng bit c gii hn ThS. Trn Thanh Tng ...
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