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8/7/2019 ngan_hang_cau_hoi_ve_tinh_0015

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TRNG I HC K THUT CNG NGHIPKHOA IN T

B mn: in t Vin thng

NGN HNG CU HI THI KT THC HC PHN

HC PHN: THNG TIN V TINH(3 TN CH)

DNG CHO O TO BC I HC THEO HC CH TN CHCHUYN NGNH IN T VIN THNG

THI NGUYN 7/2007


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TRNG I HCK THUT CNG NGHIP

Khoa in tB mn: in t vin thng

CNG HO X HI CH NGHA VIT NAMc lp T do Hnh phc

Thi Nguyn, ngy 31 thng 7 nm 2007

NGN HNG CU HI THITHNG TIN V TINH

S dng cho h i hc theo cc chuyn ngnh: in t vin thng.

1. NI DUNG NH GI THI KT THC HC PHN

- Sinh vin cn nm bt c cc khi nim c bn trong hc phn nh c im,bng tn s dng, cu hnh h thng. Tm hiu v v tinh, trm mt t cng vi

cc k thut trong thng tin v tinh. Tnh ton suy hao, cc tham s cho ngtruyn dn v thit k tuyn truyn dn trong thng tin v tinh. Tm hiu hthng thn tin v tinh VSAT cng nh tnh hnh thng tin v tinh ca nc ta vkhu vc.

2. PHNG PHP NH GI

Thi kt thc hc phn l thi vit vi thi lng 90 pht, chm im theo thangim 10.

3. NGUYN TC T HP THI

- Mi thi c 3 cu hi.

- Mi thi c t hp t 2 cu hi l thuyt (phn 4.1; 4.2) v 1 cu hi bi tp(phn 4.3).

4. NGN HNG CU HI

4.1. CU HI LOI 1 (3 IM)

1. Trnh by cc c im ca thng tin v tinh?

2. Hy gii thch ca s sng l g? Nu cc bng tn thng c s dngtrong thng tin v tinh?

3. Trnh by cc bin php c th s dng tng bng tn trong thng tin vtinh?

4. Trnh by cu hnh ca mt h thng thng tin v tinh?

5. Trnh by nhng hiu bit ca mnh v mt v tinh thng tin?

6. Trnh by cu hnh ca mt v tinh thng tin? Nu chc nng c bn ca n?

7. Phn tch chc nng, nhim v ca b pht p v tinh?

8. B pht p tuyn tnh l g? Hy phn tch nguyn l lm vic ca n?9. B pht p bo ho l g? Hy phn tch nguyn l lm vic ca n?

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10.iu ch tng h l g? Trnh by cc bin php lm gim iu ch tngh.

4.2. CU HI LOI 2 (3,5 IM)

1. Trnh by nhng hiu bit ca mnh v mt trm mt t?

2. Cu hnh in hnh ca mt trm mt t gm nhng phn no? V v nucc chc nng chnh ca n?

3. B khuych i tp m thp (LNA) l g? Cc yu cu k thut ca n? Cnhng loi LNA no thng c s dng trm mt t?

4. Ti sao li phi bm v tinh? C nhng phng php bm no; nguyn lbm ca phng php ?

5. C my loi a truy nhp thng c dng trong thng tin v tinh? K tnv trnh by nguyn tc a truy nhp ?

6. Th no l a truy nhp ngu nhin? So snh cc gia cc giao thcALOHA, ALOHA bc b chn lc v S ALOHA?

7. Trnh by cc ngun tp m (v nguyn nhn) nh hng n tuyn lin lctrong TTVT?

8. Nu cc bc tnh ton suy hao do ma trn tuyn truyn dn trong thng tinv tinh?

9. Trnh by cu hnh ca mt h thng TTVT VSAT, chc nng v nhim vca tng phn trong n?

10.Em c nhng hiu bit g v mt trm VSAT?

4.3. CU HI LOI 3 (3,5 IM)

1. Tnh t s C/N0 v v th mc cng sut ca tuyn ln khi khng c mavi gi thit TM khng nm trung tm vng ph sng ca v tinh vi ccs liu sau:

S liu ca TM S liu ca v tinhCng sut my pht PTX = 100 (w) Gc na bc sng 3dB = 2 (0)Suy hao Fido LFTX =0,5 (dB) Suy hao Fido LFTX =1 (dB)Tn s tuyn ln f U = 14 (GHz) Hiu sut anten = 0,55ng knh anten D = 4 (m) H s tp m F = 3 (dB)Hiu sut anten = 0,6 Nhit tp m Fido TF = 290 (0K)Gc lch hng pht T = 0,1 (0) Nhit tp m Anten TA = 290 (

0K)Gc lch hng pht R = 0,1 (0)

S liu chung: - Khong cch ng truyn: d = 40.000 (km).

- Suy hao kh quyn: LAG = 0,3 (dB).

- Suy hao do ma bng tn Ku: Lrain = 13 (dB).

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2. Tnh t s C/N0 v v th mc cng sut ca tuyn xung khi khng cma vi gi thit TM nm bin ca vng ph sng ca v tinh vi cc sliu sau:

S liu ca TM S liu ca v tinhSuy hao Fido LFTX =0,5 (dB) Cng sut my pht PTX = 12 (w)

ng knh anten D = 4 (m) Tn s tuyn xung fD =11 (GHz)Hiu sut anten = 0,6 Gc na bc sng 3dB = 2 (0)H s tp m F = 2,2 (dB) Suy hao Fido LFTX =1 (dB)Gc lch hng thu R= 0,1 (0) Hiu sut anten = 0,55Nhit tp m Fido TF = 290 (0K)Nhit tp m Anten TG = 45 (0K)

Tsky = 20 (0K)

Tm = 275 (0K)S liu chung: - Khong cch ng truyn: d = 37.000 (km).


- Suy hao do ma bng tn Ku: Lrain = 7 (dB).

3. Tnh t s C/N0 v v th mc cng sut ca tuyn ln khi c ma vi githit TM khng nm trung tm vng ph sng ca v tinh vi cc s liusau:

S liu ca TM S liu ca v tinh

Cng sut my pht PTX = 120 (w) Gc na bc sng 3dB = 2 (0

)Suy hao Fido LFTX =0,5 (dB) Suy hao Fido LFTX =1 (dB)Tn s tuyn ln fU =14,2 (GHz) Hiu sut anten = 0,5ng knh anten D = 5 (m) H s tp m F = 3,5 (dB)Hiu sut anten = 0,6 Nhit tp m Fido TF = 290 (0K)Gc lch hng pht T = 0,1 (0) Nhit tp m Anten TA = 290 (

0K)Gc lch hng thu R= 0,1 (0)

S liu chung: - Khong cch ng truyn: d = 38.000 (km).


- Suy hao do ma bng tn Ku: Lrain = 13,5 (dB).

4. Tnh thi gian lin lc ti a vi gc ngng ca trm mt t l: 200,qu o ca v tinh l qu o trn c cao l: h = 2km. V tinh quay tTy sang ng v c hai cng trn mt phng xch o. (v s v giithch).

Cho cc gi tr: R = 6400 km; = 3,986.105 km3/s2

5. Tnh thi gian lin lc ti a vi gc ngng ca trm mt t l: 150

, quo ca v tinh l qu o trn c cao l: h = 1.500.000m. V tinh quay

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t Ty sang ng v c hai cng trn mt phng xch o. (v s v giithch).


6. Tnh gc ngng ti thiu ca mt trm mt t sao cho thi gian lin lc tia l: tmax 20 pht, qu o ca v tinh l qu o trn c cao l: h =

2.000.000m. V tinh quay t Ty sang ng v c hai cng trn mt phngxch o. (v s v gii thch).


7. Tnh EIRP cn thit lin lc vi 1 v tinh bay cao 1800000m di thngtn ti thiu l 5MHz, C/N t nht l 10dB, gc ngng 250 hoc cao hn,G/T=7dB, f=4800MHz. (Tnh khi c hiu ng Doppler v khi khng c hiung Doppler)?

8. Tnh G/T ca ES bit EIRP ca v tinh GEO l 14dB, truyn dng bit vi tc

256kbps, s dng phng php iu ch QPSK. Yu cu u ra ca phnt tuyn tnh l C/N 10dB. Tn s cng tc l f = 4020MHz.

- Nu mun BER khng i khi dng phng thc iu ch 256QAM thG/T l bao nhiu??

9. Tnh EIRP ti thiu (2 trng hp khng tnh v tnh n hiu ng Doppler)ca VT qu o trn cao 1850km trn cng mt phng vi ES, c gc ngng 160, G/T ca ES l -25dB, tc truyn 9kbps BPSK yu cu C/N tithiu 10dB, tn s cng tc l f=2,3GHz.

10.Cho cc s liu sau:

Cho cc s liu sau n v chun Gi trC/NG/TTc truyn VPhng thc iu ch 1Phng thc iu ch 2Tn s cng tc rng bng tnKhong cch ng truyn

dBdBkb/sBPSK256QAMMHzHzKm

1217256

25611000

36.000

1. Tnh cng sut bc x ng hng tng ng.2. Nu mun BER khng i khi dng phng thc iu ch 2 th EIRP l

bao nhiu?

11.Cho cc s liu sau:

Cho cc s liu sau n v chun Gi trC/N

EIRPTc truyn V

dB

dBb/s

10

14512000

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Phng thc iu ch 1

Phng thc iu ch 2

Tn s cng tc

Khong cch

QPSK

256QAM

MHz

km

4

256

4204

37.000

1. Tnh nhy thu.

2. Nu mun BER khng i khi dng phng thc iu ch 2 th G/T l

bao nhiu?

THNG QUA B MNTRNG B MN

THNG QUA HI NGKHOA HC GIO DC KHOA IN T

CH TCH

TS. Nguyn Thanh H TS. Nguyn Hu Cng

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