Điều chế TTL và ứng dụng trong thông tin quang

May phat xung eo nhiem vu tao tin hieu so mSu cho qua trinh truyen din qua cap sgfi quang, trong truang hgp c6 tin hieu thong tin so thuc cau noi jumper U4-U6 dugc tach ra va tin hieu t

BAO CAO TOM TAT D E TAI N C K H CAP DHQG

1-Ten de tai; Dieu che TTL va ung dung trong thong tin quang

Mas6QT-99-05

2- Chu tri de tai: PGS.TS Vu nhu Cuong

3- Cac can bp phoi hap

Thac Sy Truofng vu B^ng Giang

C\x nhan Chir diic Trinh

- NCV Pham thi Tuyet

- Mot so sinh vien khoa CN DT-VT

4- Tom tat ket qua nghien curu

Tim hieu ve dudng truyen thong tin quang

Tim hieu ve dieu che TTL, ling dung phat va thu tin hieu quang da du'Oc dieu

che hkng phuong phap dieu che noi

Che tao bo phat va thu tin hieu quang

5- Cac ket qua dat dupe

Tong quan thong tin quang- Giao trinh TTQ

- Thiet ke lap rap mot so phan tii cho he thong truyen dSn tin hieu thong tin quang

Xay dung cac bai thuc tap TTQ ve cac van d6 tren

Dao tao 4 cii nhan CN DT-VT ve thong tin quang hoc

6- Tinh hinh kinh phi de tai

Da dupe chi dung nhu du toan

Ha ngi ngay 20 thdng 5 nam 2003

Chii tri de tai

PGS.TS Vu nhu Cuong

Xac nhan ciia co quan chii irVjk^

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GS.ISKH: t^/%^4i€^€^t ^iyncl ^^nwf

truan

Xac nhan ciia hoa hoc tu nhien

^^ Mu.Suu'^S MAW

O A l H O C O i / ' • • ^ t A HA N O i

TRUNG TAM ' ONG TIN THU ViEN

\^ ^~'-BAO CAO TONG KET

DE TAI CAP DAI HOC QUOC GIA

''Dieu che TTL vd ung dung trong Thong tin quang

K' Giai thieu ve de tai

I- Ten de tai:

"Dieu che TTL va img dung trong Thong tin quang"

Ma so QT 99-05

II- Chu tri de tai: POSTS Vu nhu Cuang

Luc luong tham gia d6 tai: Cac can bo phoi hop

- Thac Sy Truong vu Bang Giang

Cu nhan Chu due Trinh

- NCV Pham thi Tuyet

- Mot so sinh vien khoa CN DT-VT

III- Thai gian thuc hien: 24 thang 1999-2000

I V - Xuat xii ciia de tai

Do nhu cau thong tin doi hoi truyen dung luong ngay cang 16n, toe do truyen ngay eang nhanh den muc eae he thong truyen din truyen thong : eap doi xiing , eap dong true, song vi ba, thong tin ve tinh kh6ng the dap ling duae Dam duong nhiem

vu nay ehi eo the la he thong thong tin quang hoc vai song mang tan so Idn 10^-10^ Hz

va toe do eao c6 the nang dan len tir Mbit/s-Gbit/s va den Tbit/s.Cho den nay thong tin quang da trai qua bon the he The he thii tu dang duoc thuong mai hoa, duoc dac trung bing cong nghe ghep kenh quang DWDM eo su dung khuyech dai quang sgi pha tap Erbium Toe do truyen din eo the dat tai hang tram Gbit/s The he thii nam dang trong thu nghiem vdi day hua hen The he nay la the he giai quyet van de tan sic ciia sai quang duae dae trung bing cong nghe truyen din Soliton Co the noi he thong

TTQ CO nhung uu viet khong the thay the v6 toe do truy6n din, vt dung luong eung

nhu chat luong thong tin

Thong tin quang nhap vao Viet nam vao dau nhung nam 90 cua the ky 20 Nam 1991 Bo mon Quang va Quang pho khoa Vat Ly truang DHTH cu nay la truang DHKHTN bat dau nghien euu ma ehuyen de TTQ.' Nam 1996 Khoa CNDT - VT truang DHKHTN ra dai , tiep tue nghien euu dao tao cac cir nhan DT - VT \'ai cac khoa luan ve TTQ, xay dung cac thi nghiem, thuc hanh ve TTQ cho SV va hoc vien eao hoc Viee nim bit cong nghe mai, dao tao cac ehuyen gia ve llnh vue nay la mot doi hoi cap thiet Do chinh la ly do hinh rhanh de tai nay vao nam 1998

V- Muc tieu ciia de tai bao gom:

1 Tim hieu viee ung dung dieu che TTL trong TTQ vi he thong truyen din TTQ

la he truyen din so

2 Thifi't ke lip rap cac mach thu phat tin hieu quang dieu che TTL

3 Xay dung mot so bai thuc tap vi TTQ

4 Dao tao cac cu nhSn DT-VT lam khoa luan ve TTQ

B Cac Mt qua daf dirge

1- T6ng quan th6ng tin quang- Giao trinh TTQ Phu luc 1

2- Thifi't ke lip rap mot so phin tu cho ht ihong truyen din tin hieu th6ng tin

quang, Va xSy dung cac bai thuc tap TTQ ve cac van de trSn Phu luc 2

He th6'ng thong tin sgi quang TTL/EFO la mot cong cu tuyet hao de de phat tin hieu so TTL dieu che cuong do anh sang phai tu nguong quang( la died phat quang

LED hoac diod laser LD ) Sa 66 khoi cua he thong phat va thu tin hieu TTL dugc m6

ta or hinh sau

Hinh 1 Sa 66 khoi cua he thong thu phat so quang TTL lOMbit/s

Nguon quang dugc gin vao diu noi FC de ghep noi vai sgi quang Ve phia diu thu sgi quang dugc noi vai dau do quang thong qua diu n6i FC Diu do quang chira m6t Ph6 to di 6t PIN ( hoac APD ) Dong dien ra cua diu do quang dugc

khuye'ch dai bing mot bg khuyecli dai ehuyen ticp cung cap m6t dien ap a loi ra Sau

do la m6t b6 khuye'ch dai dai rgng va mot mach nguon TTL tuang thich Di thuc hidn

kiem tra tren cac mach, khoi mach con ehira eon chtJa mot may phat xungthay doi duae tin s6

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Hinh 3 Sado nguyen ly may phat xung quang 10Mbps

L May phat:

So 66 nguyen ly cua may phat xung quang duoc trinh bay tren hinh 3 May

phat (transmitter) bao gom may phat xung TIL va bo dit^u che dong bom cho laser diode

a May phat xung TTL tan so bien doi:

May phat xung TTL (TTL Generator) tan so bien doi c6 dai tan so c6 the thay

d6i tir 500kHz den 5MHz hoac tu IMHz den lOMHz Trong ca dai tan so, ti Ic giua d6 rong va do r5ng xung ia 1:1 va khong thay d6i vdi bien do 5V May phat xung dira

tren ca so* vi mach 74HC14 May phat xung eo nhiem vu tao tin hieu so mSu cho qua

trinh truyen din qua cap sgfi quang, trong truang hgp c6 tin hieu thong tin so thuc cau noi (jumper) U4-U6 dugc tach ra va tin hieu thong tin dugc dua thang vao bo dieu che

laser vh dugc kiem tra tai didm TPl I-Rnh 4 cho thay dang tin hieu loi ra ciia may

phat xung TTL (a) va dang tin hieu thu dugc sau khi qua he truyen dfm quang (b) tai toe do 5Mbps (tin hieu dugc do qua day do suy hao 10 Ian)

b Bo dieu che dong bom cho laser diode:

Bp dieu che dong bo'ni olio laser diode sir dung vi mach 74HC00 cung cap dong bam cho laser diode LD gom dong tin hieu ac tren nen mot chicu dc c6 the thay doi bien do bing bien tra R2 • Dong bam cho laser diode dugc kiem ua tai diem TF^2

th6n« qua sut the tren dien tra tai laser R^ (10 Q) Hinh 5 lh6 hicn ii'n hieu bom vao

laser gom dong dc va ac

Laser diode a day la module laser don mot phat a buoc song 1310nm c6 ddu noi connector FC Module phat dugc noi vdi module thu photodiodc c6 dau noi

connector FC thong qua adaptor quang va day nhay sgi quang (Fiber)

2 May rhu :

Sa do nguyen ly cua may thu (Receiver) xung quang trinh buy tren hinh 6

Module tliu su dung a day c6 tien khuech dai ehuyen tra khang gdn ben trong

(in-situ) boat dong vdi bang thong tdi da 150MHz, do nhay thu -37dBm Tin hieu tliu

Hinh 4: Tin hieu loi ra ciia may phat

xung TTL (a) va tin hieu thu dugc sau

khi qua he truyen ddn quang (b) vdi toe

do 5Mbps

Hinh 5: Tin hieu bo"m vao laser: I^^=40mA, I,,-20mA , '

dugc tu PIN photodiode sau khi qua bo tien khuech dai (c6 the kiem ira lai diem 'IIM )

di vao mach sua dang xung tren ca sd IC MC 10116 Dang tin hieu bi meo tren dirdng truyen dugc phue hoi dan sau khi di qua cac tiing ciia IC sua dang Tin hieu nay c6 the kiem ira d diem kiem tra TP4 Sau do, tin hieu dugc di qua phan khuech dai cong suat

(buffer) tren ca sd transistor 2N2905 va cudi cluing duae sua dang lai Ian nun bdi IC

74HC14 Cac tfn hieu TTL loi ra cd pha trung va ngugc pha vdi tin hieu loi vao dugc dua ra qua cong PI va P2 Hinh 7 bieu dien cac tin hieu loi ra nay d tdc do 10Mbps

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Hinh 6: Sa do nguyen ly cua may thu xung quang

Nlid CO b6 tien khuech dai do nhay eao va do khuech dai 16*n cung nhu cac bg phan sira dang tin hieu dan dfin nen t^n sd tin hieu Idi vao may phat cd the thay doi trong mdt dai rdng (500kHz -^ 5MHz) ma ti le do rgng va do rdng xung viln dugc dam

bao a loi ra may thu Hinh 9 la dang tin hieu TIL d dau ra may phat xung va tin hieu

thu dugc d dau ra cua may thu quang vdi tan sd 500kHz He thdng thu phat quang cung cd the hoat dong d tiin sd thap ( dai KHz)

Hinh 7: Tin hieu d hai loi ra ciia may thu 4dc do 10Mbps

3 .Vlay do cong suat quang:

May do cong suat quang loi ra ciia LED laser diode cho phep do cong sua't anh sang d budc song i300nm vdi hai dai do 0->lm\V va 1-rlOmVV (do chmh xac

±5%) May do sir dung ddu do PLN photodiode InGAsP cd connector quang FC va adaptor quang ihuan tien cho viec do cong suat loi ra ciia module phat quang hoc, Ket

qua do dirge hien thi tren man tinh ihi Idng May do cong suat quang dugc nudi b^ng

nguon pin 9V thuan tien cho viec do dac km dong

4 Bg suy hao quang:

Bg suy hao quang su dung sgi quang dan mode 9/125um cd gan connector

quang FC va adaptor quang thuan lien cho viec su dung trong mang thong tin quang

Do suy hao cd dinh hi lOdB cho budc song 1300nm (cd the thay ddi do suy hao khi

c&n tliiet)

5 Cac ung dung dao tao vc thong tin quang ciia he thi nghiem he thdng tin quang sgi sd hoa 10Mbps:

a) Giiip hoc vien nhan biei cac linh kien , thiet bi ca ban trong he thdng thong tin quang ( may phai quang (E/0), may thu quang (0/E) module ihu phai quang, may

do cong suat quang, bg suy hao quang, )

b) Do dac trung cong sual quang Idi ra phu ihugc dong kicli ciia module phat quang d che do kich b;ing dong xung Do cong suai quang Idi ra ciia module phat d bucic song 1300nm

c) Tim hie'u ve may phat xung TTL trong mot dai tan sd rgng (500kHz tdi lOMHz) lim hieu ve nguyen ly dieu bieii theo cudng do cho laser diode

d) Tim hiCu ve qua trinh thu tin hieu sd TTL qua sgi quang: khuech dai iin hieu, sua dang tin hieu khuech dai cong suat, de khoi phuc dang tin hieu

e) 'nuc hanh thiet ke dudng truydn sgi quang dan gian, tinh toan do suy hao ciia dudng truyen do du trff cong suat,

0 Tliuc hanh truyen din qua cap sgi quang cac loai tin hieu sd lieu, tin hieu thoai duae ma hoa PCM, Manchester,

2 Bg bien dieu PCM va thuc hanh ma hoa Manchester:

B6 bien dieu PCM va thuc hanh ma hoa Manchester ket hgp vdi thiet bi thi nghidm thdng tin quang sgi sd hoa tdc do 10Mbps (lam thiet bi dau cudi quang) dtrgc trinh bay trSn hinh 12

Hlah 12: Bg bien dieu PCM va thuc hanh ma hoa Manchester ket hgp

vdi thiet bi thi nghiem thdng tin quang sgi sd hoa tdc do 10Mbps

a) He thdng di^u che PCM:

Ky thuat didu che PCMjhuc hien qua trinh ehuyen doi tin hieu thoai tuong tu thanh luong PCM sd tdc do 64 Kb/s la mot ky thuat dugc su dung kha pho bien trong Iinh vue truyen thong hien nay Trong he thdng dieu che PCM, chiing tdi da su dung vi mach MC 3057 Day la chip codec dugc su dung rong rai trong cong nghiep thdng tin lien lac He thdng cd the' chia thanh cac khoi chinh nhu tren hinh 13

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Hinh 13: Sadd khoi cua bg bien dieu PCM va thuc hanh ma hoa Manchester

1 Khdi tao xung nhip (TIMING):

Xung nhip cung c^'p cho he thdng gom: xung nhip chu (Master clock), xung

nhip tao khung (TX frame): tdn sd 8 KHz, xung nhip bit (bit clock): tiin so 64 KHz

Cac xung nhip dugc tao ra tu khoi tao xung nhip dung thach anh va su dung mach CD

4040 de thuc hien chia tan sd cung cS'p cho he thdng

2 Khoi dieu che PCM (COMPANDED PCM):

Viec dieu che PCM dugc thirc hien nhd su dung vi mach CODECMC 3057 vi mach nay thuc hien dieu che PCM theo luat A, hoat dong vdi cac nguon xung nhip dugc cung cap bdi klidi tao xung nhip cua he thdng Tin hieu dua vao de thuc hien

dieu che cd thi la tin hieu hinh sin diing de khao sat, hay tin hieu thoai dua vao loi vao

Mic in Cac tin hieu nay cd bien do khoang IV- SV^^^va dugc Igc trude bang mach Igc chdng chdng pho cd dai thdng 300 - 3400Hz Cac tin hieu Analog tren sau khi dugc dieu che de tao thanh luong PCM 64Kb/s dugc truyen tren mdi trudng truyen la mot sgi cap quang dan mode vdi thiet bi d^u cudi quang la thiet bi thi nghiem thong tin

quang sgi so hoa tdc dd 10Mbps

Tai nai thu tin hieu thu se'dugc dua den khdi PLL de tach xung nhip dong ho (khoi nay su dung vi mach CD4046) va sau do xung nhip dugc su dung de thuc hien lay mc\u tin hieu thu, tao lai tin hieu PCM phat Luong PCM sau khi tao lai dugc dua den Codec va Codec se thuc hien viec giai dieu che de thu lai tin hieu thoai ban dau Trong he thdng nay Codec hoat dong d che do dong bg, cac xung nhip RX frame va

RX bit clock dugc cung cap bdi xung nhip tach ra tij" lu6ng PCM nhan dugc

I _

Hinh 14: Sa do nguyen iy bg bien dieu PCM va mii hoa Manchester

3 Khdi ma hoa va giai ma Manchester (MANCHESTERCODING and DECODING):

Di tang dd tin cay, tinh hieu qua va kha nang dinh thai khi truyen du lieu sd la

thudng six dung loai ma dudng(line coding) la ma Manchester Trong he ihdng nay,

viec thuc hien ma hoa Manchester luong data PCM 64 Kb/s dugc thuc hien dc dang nhd sir dung vi mach 74LS86 ket hgp vdi xung nhip bit 256Kb/s Tin hieu sau khi

dugc ma hoa Manchester cung se dugc truyen tren moi trudng truyen la sai quang dan

mode vdi thiet bi dau cudi quang la thiet bi thf nghiem thdng tin quang sgi sd hoa tdc

do iOMbps Tai nai thu ta cung tien hanh tach xung nhip va lay m5u de tai tao ludng PCM ban dau tir luong PCM dugc ma hoa Manchester

Hinh 14 trinh bay sa dd mach dien cua he thdng Mot sd ket qua thu dugc cua he thdng dugc irinh bay tren cac hinh 15a 15b, 15c, 15d Cac hinh nay cho tliay dang tin hieu sin ifin md phdng tin hieu thoai, tin hieu sin tiin dugc dieu che PCM tin hieu PCM trude va sau khi truyen qua cap quang, tin hieu PCM dirge ma hoa Manchester

va tin hieu sin tan thu dugc sau klii dieu che PCM va truyen qua cap sgi quang vdi Ihiet bi dfiu cudi la thiet bi thi nghiem thdng tin quang sgi sd hoa tdc do 10 Mbps Cac tin hieu nay dugc do tai cac diem do khac nhau cua bg ma hoa, thuc hanh bien dieu

Ket qua thu dugc tir he thdng phii hgp vdi cac chufin yeu cau doi vdi he tiuyen d3n PCM va quang

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Hinh 15: a) Tin hieu sin tiin ban dau (tren) va tin hieu sau khi diroc dicu che PCM (dudi)

b) Tin hieu PCM tructe (tren) va sau (dudi) khi liuyeu qua cap quanii,

c) Ludng tin hieu PCM dugc ma hoa Manchester trir()c (tren; \a sau (duiu) kh

truyen qua cap quang

d) Tin hieu sin tan ban dau (tren) va tin hieu ihu duoc sau khi giai dieu che PCM cd su dung mdi trudng truyen diln quang (dudi)

3 Cac urng dung dao tao ve thong tin quang ciia he thi nghiem do thdng sd linh

kien quang dien tiir, thuc hanh bien dieu:

1 Giup hoc vien thuc hanh cac phep do (ghep noi vi tinh) cac dac trung ca ban cua LED, laser diode va module phat (juang hoc nhu:

a) Do dac trung cong suat quang loi ra - dong bam dc (P-I) d nhiet dd phdng va tai cac nhiet dd khac nhau, xem chi tiet ti^g ph^n cua dd thi

b) Do dac trung dong - the (I-V)

c) Do phan bd trudng xa (phan bd khong gian ciia chiim tia laser) (P-A) d cac hudng khac nhau ciia mat phang ehuyen tiep p-n cua LED, LD so vdi dfiu thu photodiode

2 Giiip hoc vien tim hieu qua trinh bien dieu va ma hoa tin hieu thoai vdi mdi trudng truyen dan la cap dien va cap quang:

a) Thuc hanh bien dieu PCM tin hieu thoai va giai bien dieu PCM cho mot kenh thoai khi sir dung mdi trudng truyen dan la cap dien va cap quang, so sanh cac ket qua thu dugc

b) Thuc hanh ma hoa Manchester tin hieu PCM va giai ma hoa khi sir dung mdi trudtig truyen din la cap dien va cap quang, so sanh cac ket qua thu dugc

c) Thuc hanh'bien dieu, ma hoa vdi tin hieu sin tan mau va vdi tm hieu thoai thuc tu Micro

IIL Kha nang mo rgng thiet ke he thf nghiem co sd ve thong tin quang sgi sd hoa tdc do IOMbps va do thong sdcac linh kien quang dien tu:

- Thiet bi thi nghiem thong tin quang sgi sd hoa tdc do IOMbps cd ihi thiet ke

cho module thu phat quang hoc da mot hoat dong d budc song 850nm (che tao module

thu quang cd ti6n khuech dai ben trong) di cd the thuc hanh do tan sac sgi quang

- Thiet bi do cac thdng sd linh kien quang dien tu cd ihi thiet ke vdi card bien

ddi AD/DA tdc do eao (12-bit) cho phep do phan giai do eao han, tang cudng them cac tien ich khi do cac dac trung linh kien va tang them do thuan Igi cho ngudi sir dung

- Cd the md rgng thiet ke thiet bi thuc hanh bien dieu va ma hoa di thuc hien

di6u che va ghep kenh doi vdi nhieu ludng PCM vdi cac loai ma dudng khac nhau: HDB Biphase v.v

13