I HC QUC GIA TP.HCM

TRNG I HC BCH KHOA

Khoa in in t

..0O0..

Mn: THNG TIN SI QUANG

Bi tp: 1, 2 v 3

Ging vin: TS. Phm Quang Thi

Nhm: Nguyn Xu Lin v L Quang Tn

Lp: Cao hc Vin thng 2013

TP. H Ch Minh, 10 - 2014

Bi tp 1: LED system, change bit rate from 100 Mbps to 300 Mbps. Maximum allowed BER 10-9. Find the

maximum bit rate.

S mch:

- Bit rate at 100 Mbps:

- Bit rate at 140.49Mbps:

- Bit rate at 300 Mbps:

Kt lun: Sau khi thay i tc bit vi cc gi tr khc nhau nm trong khong t 100 Mbps n 300

Mbps, kt qu t c l khi truyn vi t l bit l 140.49 Mbps cho tc li bit (BER) gn thp nht

l 0.999857 x 10-9 sp x vi BER cho php ti a l 1 x 10-9. Ngoi ra cng cho thy rng khi truyn tc

bit cng cao th BER cng tng.

Bi tp 2: LD system, change bit rate from 1 Gbps to 20 Gbps. Maximum allowed BER 10-9. Find the

maximum bit rate.

S mch:

- Bit rate at 1Gps:

- Bit rate at 5.753Gbps

- Bit rate at 20 Gbps:

Kt lun: Sau khi thay i tc bit vi cc gi tr khc nhau nm trong khong t 1 Gbps n 20 Gbps,

kt qu t c l khi truyn vi tc bit l 5.753Gbps cho t l li bit (BER) gn thp nht l

0.996257 x 10-9 sp x vi BER cho php ti a l 1 x 10-9. Ngoi ra cng cho thy rng khi truyn tc

bit cng cao th BER cng tng.

Bi tp 3: For the LD system. Set:

- Bit rate: 1Gbps - Bit sequence length: 16 bit - Laser bias current to 20 mA

Obeserve the received signal. Explain the results.

S mch:

Kt qu m phng:

Nhn xt: khi cho di chui bit l 16 bit/s, ph tn hiu dnh chm nhau, t l li bit t cao nht.

Nhn xt: khi dng bias (20mA) thp hn dng ngng 33.457 mA, Laser khng pht sng. Tn hiu pha

thu hu nh l khng c tn hiu. Ph tn hiu b ko dn ra.