Cho mnh hi v tn s ca vibaTn s thu v pht ca viba cch nhau bao nhiu. Ti sao nh phi cch nhau nh th.Thanks all tr li t m cu hi ny khng d v n lin quan n nhiu th. Vn tt th nh sau:

1. Khong cch gia tn s thu v pht ca vi ba cn phi ln tn hiu pht vng li ng-ten thu cng trm nh, trnh gy nhiu pht-thu (xuyn nhiu u gn);2. Trong mt bng tn c quy nh, mt di c dnh cho pht i vi nhiu lung vi ba v mt di c dnh cho thu vi cc lung , cc lung c phn b v tn s v phn cc theo cc phng n tn s CCP (Co-Channel Plan) hay ICP (Interleaved Channel Plan) c quy nh theo cc khuyn ngh ca CCIR (y ban t vn quc t v v tuyn) nay lITU-R(Phn ban v tuyn thuc Lin minh vin thng quc t). Cc bng tn ny rng/hp ty theo di bng tn s cng tc trong di sng vi ba mt t v c xem xt k lng phn chia mt cch thch hp nhm t hiu qu s dng tn s tt nht. Chi tit xin xem cc reports hoc cc khuyn ngh ca CCIR/ITU-R. Khong cch gia di pht v thu trong mt bng tn cng phi bo m nhiu pht-thu nh. Gi s mt bng no dnh cho N lung vi ba, khong cch gia cc lung (khong cch gia cc sng mang pht ca 2 lung cn k) l W, khong cch tn s phng v xuyn nhiu pht-thu l W1 th khong cch gia tn s thu/pht ca cng mt lung ti thiu s l N.W+W1.y con s c th y: (Mnh va hi 1 chuyn gia viba)Khong cch thu pht cch nhau: 266 MHzCn cc knh ln cn cch nhau 28MHzChuyn gia no m gii th h MTA?

Vi li, ci khong cch knh 28 MHz y l chun ni chung dnh cho cc tuyn vi ba 3x45 MHz (R = 135 Mbps) s dng iu ch 64-QAMvi roll-off factor (RF) tiu chun l 0.35 rt thng dng M. Vi h Chu u, truyn E4 vi 64-QAMvRF= 0.35 th khong cch ny l 29.65 MHz. Khong cch gia cc knh ln cn X khng c nh vi cc h thng khc nhau. X ch yu ph thuc vo: a) Tc lung cn truyn; b) Kiu iu ch; c) H sRF...

My phn tch ph thi gian thc(20/05/2013 10:50:33 SA)Nu nh bn ang lm vic trong lnh vc nghin cu mi trng v tr, quc phng hay h thng lin lc khng dy, bn s gp phi cc thch thc nh: Mi trng ph tr nn cht tri vi nhiu lin kt ti mt im, pht sinh ra nhiu hin tng gy nhiu. H thng Rada v cc h thng tn hiu thng mi cng ngy cng pht trin.Vn v chi ph cng ang l bi ton kh bn phi thit k ra nhng thit b cng ngh cao vi mt mc gi bng hoc thp hn mc trc y.My phn tch ph thi gian thc PXA kt hp cng ngh phn tch tn hiu vi cng ngh phn tch thi gian thc

Gi tr ca cng ngh thi gian thcCc tn hiu ngy cng tr nn phc tp v kh nm bt, k thut phn tch ph thi gian thc tr nn v cng hu dng. My phn tch ph thi gian thc PXA ca Aglent s gip bn tm ra p n cho cc bi ton . y l thit b u tin trn th trng mang li kh nng phn tch thi gian thc, vic nng cp cng d dng khng cn phi thay mi phn cng hay yu cu ti hiu chun. My phn tch ph PXA mang li nhy cao, bng thng phn tch, di tn rng v kh nng gy nhiu; gip bn tm ra v o c cc tn hiu kh nm bt m bn cha th lm c iu trc y. Pht hin c cc tn hiu ngn n 5.0 ns, o c ti mc 3.57 s vi 100% kh nng gy nhiu v bin chnh xc cao. D tm vi bng thng thi gian thc 160 MHz vi di tn ln ti 50 GHzGii quyt bi ton khng cn cc thit b chuyn dng: cc my PXA c th c nng cp ln vi kh nng phn tch thi gian thc.

Kh nng quan st nhng tn hiu rt nh vi bng thng ln hn v di ng ln ti 75Db.V cui cng, bn c th kt hp my phn tch ph thi gian thc PXA vi phn mm 89600 VSA ca Agilent to ra mi gii php trong vic phn tch cc tn hiu phc tp mang cc c trng ring.My phn tch ph

1. Tn thit b:My phn tch ph (Series Spectrum Analyzer)2. K m hiu:Model R31313. Hng sn xut/nc sn xut:Advantest - Japan4. nh chp ton cnh thit b, m t thit b

M t thit b: My c s dng phn tch ph ca tn hiu.5. Thng s k thut ch yuMy phn tch ph R3131 c cc thng s k thut nh sau: phn gii : n 1HzTn s Span: Zero, 50kHz, 3GHz.Di tn: 9kHz 3GHz (-3dB)Nhit lm vic: 00C +500CHin th: 5 inches LCD mn hnh tinh th lngCh hin th: Dng sng trn mn hnhGhi nh d liu: Lu tr thng tin vo b nh ca my, c **a mm ph tr bn ngoi. Cng RS 232 cho kt ni vi my tnh v my in6. Cc thng s sn phm m thit b o c hoc ch to, tnh ton c, nhy, phn gii

7. Mt s kt qu in hnh (cc s , biu , gin , th, ph, giao din lm vic in hnh)

8. Yu cu c bn i vi mu o, i tng kho st (kch thc, trng thi mu, cc x l c bit):Tn s ca tn hiu cn phn tch nm trong khong t 9kHz n 3GHz.9. Lnh vc p dng v gii hn lm vic ca thit b:Phn tch ph ca cc dng tn hiu.

Ngun :Phn tch ph ca tn hiuhttp://svptit.vn/@forum/khu-vuc-dien-tu-vien-thong/99507-phan-tich-pho-cua-tin-hieu.ptit#ixzz2Ua15OYbPDin n Sinh Vin Hc Vin Cng Ngh Bu Chnh Vin Thng H Ni.Follow us:svptit.vn on Facebook