CHNG 4: O KIM MNG CP NG1. Mng vin thng gm thnh phn?A. H thng chuyn mch, h thng truyn dn, h thng ngoi vi.2. Mng cp thu bao gm?A. Mng cp ng thu bao, mng cp quang thu bao.3. Mng cp ng thu bao s dng ?A. Kt ni t nt chuyn mch/ im truy nhp n nh thu bao.4. Mng cp ng thu bao gm cc thnh phn?A. Gi phi dy chnh (MDF), mng sng cp, phin ni dy, t cp, hp cp, cp, h thng cng b.5. Mng cp quang thu bao s dng?A. Kt ni t nt chuyn mch/im truy cp n nh thu bao.6. Mng cp quang thu bao gm cc thnh phn?A. Gi phi dy cp quang (ODF), mng sng quang, t cp, n v mng quang (ONU) v h thng cng b.7. MDF l g?A. Gi phi dy chnh ca mng cp ng thu bao.(phn bit vi ODF ca mng quang).8. Mng cp quang trung k chia lm my cp?A. 2 cp mng trung k cp I v mng trung k cp II.9. Mng cp quang trung k cp I s dng?A. Thuc mng vin thng ng trc quc gia, quc t c s dng kt ni trung k gia cc tng i trung tm-chuyn tip, chuyn tip-chuyn tip, chuyn tip-cng, cng-cng.10. Mng cp quang trung k cp II s dng?A. Thuc mng vin thng ni tnh, thnh ph, c s dng kt ni trung k gia cc tng i trung tm-trung tm, trung tm- tng i chuyn tip ni ht, trung tm-v tinh/im truy nhp.11. H thng h tr, bo v mng ngoi vi gm?A. H thng hm h, cng cp, ct b tng cp, trang thit b chng st cho mng cp ng v cp quang.12. Vng phc v ca mt tuyn cp chnh phn thnh?A. 3 dng: vng phc v trc tip, vng phc v qua 1 cp phi cp, vng phc v qua hai cp phi cp.13. c im ca vng phc v trc tip?A. Thu bao c kt ni trc tip vi nt chuyn mch qua mt cp chnh.14. c im ca vng phc v qua 1 cp phi cp?A. Thu bao c kt ni vi nt chuyn mch qua mt cp phi v mt cp chnh.15. c im ca vng phc v 2 cp phi cp?A. Thu bao c kt ni vi nt chuyn mch qua 1 cp chnh v 1 cp phi.16. Mng cp ng thu bao c my cch phi cp?A. 3 cch: phi cp trc tip, phi cp 1 cp, phi cp hai cp.17. c im ca phi cp trc tip ?A. Thu bao c ni vi nt chuyn mch ch qua mt hp cp.18. Khong cch thc hin phi cp trc tip?A. Thc hin phi ngay khu cc t tng i v nhng khu vc c mt dn c cao cch tng i khong 500m.19. c im ca phi cp 1 cp?A. Thu bao c ni vi nt chuyn mch ch qua mt hp cp v mt t cp.20. Phi cp 1 cp c s dng ?A. Phi ti cc khu vc th n nh c mt in thoi cao, vng phc v ca tng i n nh v l ni c nhu cu cao v dch v Internet bng thng.21. c im ca phi cp 2 cp?A. Thu bao c ni vi MDF qua mt t cp cp I, mt t cp cp n v mt hp cp chnh.22. Phi cp 2 cp s dng ?A. Phi i vi vng dn c ang pht trin hoc vng ngoi thnh, khu vc nng thn.23. Mng xng cp l?A. u ni t cp chnh ra cc t cp hay hp cp.24. Mc ch ca mng sng cp?A. R nhnh cp chnh sang cc tuyn khc nhau vi nhu cu dung lng cp cn dng trn cc tuyn cp thp hn, khng c dng t cp r nhnh cp.25. c im ca ca mng sng cp?A. Phi chu c ngp nc lu ngy.26. Dung lng ca t cp cp I?A. T 200 i n 600 i.27. c im yu cu khi t t cp?A. S dng ti u dung lng cng b, thun tin cho vic thi cng cp phi, bo dng, x l thay th cp, khng t t cp gn t phn phi in lc28. c im ca mng cp chnh?A. Phi c ngm ha ti cc trung tm tnh, thnh ph, huyn, th trn29. c im ca mng cp phi?A. Ti cc trung tm tnh,thnh ph phi thc hin trit vic ngm ha mng cp phi.30. Khong cch gia hai t cp lin k trn mt tuyn cp hoc gia cc t cp ca hai tuyn cp khc nhau khong?A. 200m-300m (ngn hn vi ni cso mt in thoi c bit cao).31. Dung lng ca hp cp ca mng cp phi?A. T 10 i n 50 i.32. T cp cp II c dung lng?A. 100 n 200 i.33. Cp vo nh thu bao?A. on cp ni t hp cp vo nh thu bao.34. Cp vo nh thu bao c lp t theo phng thc?A. Treo hoc i ngm.35. c im ca cp vo nh thu bao?A. Dung lng ca cp t 1 n 2 i, li cp c xon i v bn vi nhau tho TCN 68-153:1998, khng di qu 300m trong th.36. Cp vng l?A. Cp ni gia hai t cp cp I ca hai cp chnh trong vng phc v ca 1 tng i ni ht, hoc gia hai t cp cp II trong vng phc v ca 1 cp chnh.37. Cp vng c s dng vi mc ch?A. p ng nhu cu t chc thng tin t xut do thiu cp pht trin thu bao, thiu s cc b hoc cn pht trin dch v thu knh ringdo dng ht dung lng hoc cht lng xu cn chuyn tuyn.38. ng knh si ng ca cp vng?A. Bng ng knh si ng ca cp chnh trong trng hp cp vng ni gia hai t cp cp I v bng ng knh cp phi trong trng hp cp vng ni gia hai t cp cp II.40. i vi vng mt dn c cao bn knh phc v ca mng cp tnh t trung tm chuyn mch n hp cp kt cui vi c dy 0,4mm l?A. Khng qu 3km.41. i vi vng mt dn c cao bn knh phc v ca mng cp tnh t trung tm chuyn mch n hp cp kt cui vi c dy 0,5mm l?A. Khng qu 4km.42. i vi vng mt dn c cao suy hao ng dy t gi MDF n hp cp kt cui?A. Khng qu 7dB.43. i vi vng mt dn c cao in tr mch vng ca 1 i cp t MDF n hp cp?A. Khng qu 1000 .44. i vi vng nng thn mt dn s thp, bn knh phc v ca mng cp tnh t trung tm chuyn mch n hp cp kt cui?A. C th ln hn 4km.45. i vi vng nng thn mt dn s thp, suy hao ng dy thu bao?A. Khng vt qu 10dB.46. i vi vng nng thn mt dn s thp in tr mch vng ng dy thu bao?A. Khng qu 1200 .47. C th m rng vng phc v ca cp ng bng cch?A. S dng cp ng c ng knh 0,65mm hoc 0,9mm.48. Mc tiu lu di vi mng ngoi vi ca 1 bu in tnh, thnh ph?A. t c 90% thu bao nm trong bn knh phc v5M.116. Trong xDSL hai dy khng b ngn mch thi cn m bo?A. T s dy Tip/Ring>5M.117. Cc lp cn o khi o kim cc tham s lp 2 ca xDSL?A. Kim tra lp ATM (ATM DLAM), lp PPP, lp IP- tc truyn d liu.118. Khi kim tra lp ATM (ATM DLAM), cn kim tra?A. + ATM segment + ATM end-to-end + Qut tm vcc.119. Khi kim tra lp PPP cn kim tra?A. + Xc nh my ch PPPoA/PPPoE + Kim tra kh nng xc thc.120. Tc ti d liu trung bnh ni mng ca xDSL?A. Pd > 0,8 Vdmax v Pu > 0,8 Vumax.121. Tc ti d liu trung bnh ngoi mng ca xDSL?A. Pd > 0,6 Vdmax v Pu > 0,6 Vumax.122. o cc tn hiu lp di v kh nng kt ni lp IP cn kim tra?A. Kim tra cht lng cp ng, pht hin li cp - Kim tra cht lng tn hiu xDSL - Kim tra kt ni cho ATM - Kim tra kt qu xc thc.123. u im khi o cc tn hiu lp di v kh nng kt ni lp IP?A. C th o c tn hiu c cc lp di - D dng pht hin ra li khc phc - t ph thuc vo cc yu t nm ngoi cht lng mng.124.Cch xc nh v tr li cp bng my o phn hi min thi gian trong xDSL (Time Domain Reflectometer : TDR) ?A. Pht ra mt xung v o thi gian n phn hi ri xc nh khong cch da trn tc lan truyn ca xung.125. Nhng nguyn nhn gy ra s phn hi trong xDSL?A. H mch - Ngn mch - Cu r (R nhnh) - Cun cm (load coil).

126. Nhc im khi s dng my o phn hi min thi gian trong xDSL?A. + Gi thnh t + Ch o phn on t khch hng ti BRAS + C th kt qu cha thuy phc c khch hng nu khng o lp ng dng.127. kh dng ca mng l?A. L t l thi gian trong mng sn sng cung cp dch v cho khch hng.128. Kim tra t l lu lng s dng trung bnh)A. T s gia lu lng s dng trung bnh trong khong thi gian 7 ngy lin tip vi tc truyn d liu nh danh ca ng truyn ti hng kt ni . (yu cu 70%).129. Thi gian khc phc mt kt ni l?A. Thi gian t lc doanh nghip cung cp dch v nhn c thng bo mt kt ni cho n khi khc phc c kt ni. (yu cu: t nht 90% s ln khc phc trong thi gian quy nh).130. Yu cu t ra trong khc phc mt kt ni m bo yu cu?A. Trong ni thnh, ni th 36h; trong th trn 48h; lng x 72h;

CHNG 6. O KIM TR MNG CP QUANG131. Mng cp quang hin nay gm nhng loi ?A. Mng cp quang thu bao v mng cp quang trung k (cp I v II).132. Mng cp quang thu bao gm?A. Mng cp quang t nt chuyn mch/im truy nhp n cc nh thu bao, cp quang s dng trn mng thu bao quang cc th loi c bit133. Mng cp quang thu bao loi 1 thng thng cso bao nhiu si?A. 144 si.134. Mng cp quang trung k cp I c t chc theo ?A. Dng ring 2 si hoc 4 si.135. Tc truyn dn ca mng ring phi m bo tho mn nhu cu v lu lng?A. t nht l 7 nm.136. Cp quang s dng trn mng trung k cp I s dng loi cp c dung lng?A. T 16-24 si.137.Mng cp quang trung k cp II (c th s dng kt hp vi cp I) c t chc theo?A. Mng ring (2 si hoc 4 si) cc trm trung tm - trung tm, trung tm - chuyn tip.138. Tc truyn dn ca mng ring phi m bo tho mn nhu cu v lu lng?A. t nht l 5 nm.139. Cc th loi c bit c th s dng cp c dung lng?A. 144 si140. Cc th loi 1 c th s dng loi cp quang c dung lng?A. 96 si.141. Cc th loi II v cc th x c th s dng loi cp quang dung lng?A. 48 si142. Cp quang s dng trn mng trung k l loi?A. Cp quang n mt.143. Cp quang s dng trn mng thu bao quang c th dng loi?A. n mt hc a mt.144. Mng cp quang l mng cp c tnh t?A. Gi phi dy ODF n ODF gia hai thit b u cui quang.145. Cc thnh phn trong mng cp quang bao gm:A. Gi phi y, mng sng, h thng cng b, ct treo cp146. Trong qu trnh o kim tra nh k hoc khc phc s c cn phi:A. Tch cc i cp phi o ra khi g ODF c hai u.147. Tc truyn dn trong o kim mng cp quang cn m bo:

148. Tiu chun ca phn giao din in i vi u ra lung 2048 Kb/s:

149. Suy hao phn x nh nht ti u vo 2048 kb/s:

150. c tnh ca tn hiu in lung 34Mb/s:

151. Suy hao phn x nh nht ti u vo 34Mb/s:.152. c tnh ca tn hiu in lung 140Mb/s:

153. c tnh ca tn hiu in lung 155Mb/s:

154. Cc thit b u cui quang phi c kh nng xc nh v bo cc s c:A. S c v ngun nui TBDC BER>10-3 v BER>10-6 mt tn hiu u thu quang mt tn hiu ng b.155. Yu cu kh nng xc nh v bo cc s c c th b qua khi:A. BER>10-3 ch th khi mt tn hiu thu, mt tn hiu ng b.156. Gii hn ca cc tham s li bit:

157. Ch tiu suy hao v bng tn i vi khong lp dng si quang a mode:

158. c tnh truyn dn i vi si quang n mode:

159. H s tn sc i vi si quang n mode:

160. OPM (Opticall Power Metter) l mt dng c o:A. Cm tay c dng o cng sut pht quang rt thng dng trong k thut vin thng.161. My o cng sut OPM cho php giao tip vi my tnh qua cng:A. RS232 hoc USB.162. Cc php o dng my o cng sut quang OPM:A. o suy hao tuyn quang - o suy hao tuyn quang WDM.163. Thit b o OTDR (Optical Time Domain Reflectometer) do to ra:A. Banosky v Jnen a ra ln u tin vo nm 1976.164. Chc nng ca thit b o OTDR:A. o suy hao ca tuyn, s phn b suy hao, chiu di thc ca tuyn, v tr mi hn, v tr t si, connector...( ch cn tin hnh o mt u si m khng cn phi ct si).165. Suy hao truyn si quang c tnh:A. P(x) = Po exp (-2x) (W) hay P(x) = Po.10(-/10.x)P(x) l cng sut quang c ly x(m)Po l cng sut quang u si l suy hao trung bnh trn mi mt si quang, c n v l Neper/m.166. H s phn x trong si quang c tnh nh sau:A. R=(n1- n0)2/(n1+ n0)2. (R xp x 4% hay 14dB).167. Cng sut tn x c dng tng qut:A. Ps(t)=S.s.v..P0.exp(-2vt)168. H s tn x ngc S cu si a mode chit sut phn bc (SI):A. S=3/2.(n12-n22)/4.n12169. H s tn x ngc S cu si a mode chit sut gim dn (GI):A. (n12-n22)/4.n12170. H s tn x ngc S cu si n mode (SM):A. S=0,038(/n1.2.p)2 (2p l ng knh ng mode)171. Nguyn l hot ng ca thit b o OTDR :A. Da trn vic pht vo si quang cc xung quang ri thu nhn cc xung phn x phn tch v nh gi cc c tnh truyn dn ca si quang.

172. Mt thit b o OTDR thng c cc thnh phn c bn nh : A.Mt ngun sng Laer Diode, mt b to xung pht, mt Coupler quang, mt b tch sng Photo Diode, mt b bin i tng t/s, mt mn hin th v mt b vi x l.173. Chc nng ca Laser Diode : A. L ngun pht ra cc xung nh sng n nh pht vo si quang.174. Cc bc sng c s dng trong cc php o OTDR thng l:A. 850, 1300 nm cho si a mode v 1310, 1550nm cho si n mode.175. B to xung pht c nhim v:A. To ra cc xung in iu khin Laser diode pht ra mt xung hay mt chui xung ri rc.176. Coupler quang c nhim v:A. Truyn a ra nh sng t Laser Diode vo si quang v truyn a nh sng phn x t si quang vo Photodiode.177. Photo Diode (APD) l:A. B bin i quang/in, c nhim v bin i nh sng phn x n Photo Diode thnh tn hiu in.178. B khuch i (K):A. Tn hiu in c to ra bi Photodiode c cng rt yu, v vy c tn hiu cng sut mnh a sang b vi s l, tn hiu ny c khuch i nh b khuch i.179. Chc nng vi x l v mn hin th: A. Tn hiu phn x, sau khi c bin i A/D c a n b vi s l phn tch di s h tr ca phn mm chuyn dng.180. Nu tn hiu tn x ngc c khuch i tuyn tnh th ng biu din trn mn hnh l:A. ng cong gim dn theo quy lut hm s m. 181. Nu dng b khuch i logarit th ng biu din trn mn hnh l:A. ng thng c h s gc m. 182. Tnh suy hao ton tuyn:A. Da vo chnh lch ca cng sut tn x ngc u v cui si.183. Suy hao mi hn v khp ni c xc nh:A. Bi chnh lch cng sut tn x ngc trc v sau im ni.184. Mn hnh s quan st thy xung phn x khi:A. Khi truyn qua mi hn nng chy.185. Xc nh v tr t si quang bng my o OTDR da vo:A. Khong cch hin th trn mn hnh tnh t sn sau ca xung nh sng u si n sn trc ca xung nh sng phn x cui si.186. Xc nh v tr hn nhm si quang bng my o OTDR da vo (Khng th xc nh c v tr hn nhm khi trn tuyn c nhiu mi hn):A. Dng my o OTDR u vo mt u si, u cn li c ngm vo cht lng c chit sut tng ng vi chit sut li si sau quan st mn hnh hin th, nu cui si khng c phn x th si hn ng, nu c phn x th si hn nhm.187. Thi gian 1 xung nh sng truyn t u si n cui si ri phn x v u si l:A. t = 2.L/v . Trong : L l chiu di si v=C/n1: l vn tc nh sng truyn trong si.188. Mun o si cng di th:A. Tn s pht xung cng thp, thng thng tn s xung trong khong t 1 - 2KHz. 189. phn gii hay kh nng phn gii my o (Resolution) l:A. Khong cch ti thiu gia 2 chng ngi gn nhau m my o cn phn bit c.190. phn gii ph thuc vo:A. B rng ca xung nh sng v rng 191. C ly truyn tng ng b rng ca mt xung nh sng l:A. l=(1/2).v.T vi T l rng xung ,T cng nh th phn gii cng cao v ngc li.192. C ly ti a m my o OTDR c th o c ph thuc vo:A. Di ng ca my v suy hao trung bnh ca si quang.193. Di ng n hng SWDR (Single Way Dinamic Range) ca mt my OTDR l:A. Mc suy hao ln nht ca si quang m khi o c th quan st c t u n cui si194. Di ng ca cc my o OTDR hin nay vo khong:A. 20 - 35dB.195. Lin h gia di ng v phn gii ca mt my o OTDR:A. Xung cng rng th cng sut quang phng vo si cng ln nn di ng cng cao nhng phn gii cng km v ngc li.196. Vng cht (Dead Zone) l:A. Vng cht cp n khong cch trn mt du vt si quang sau phn x Fresnel trong mc phn x li cao hn mc tn x. Thi gian m la v phc hi nhy tn x gi l vng cht.197. Suy hao ti vng cht l:A. Khong cch sau khi c mt s phn x Fresnel cho n khi mc tn x c th c pht hin.CHNG 3. O TRT BIT198. Rung pha l:A. Nhng bin i pha ln hn hoc bng 10Hz gi l rung pha (Jitter).199. Tri pha l:A. Nhng bin i pha nh hn hoc bng 10Hz gi l tri pha (wander)200. Bin cu jitter c o bng khong n v:A. UI ( rng ca 1 bit).201. UI khng ph thuc vo:A. Dng tn hiu s, tc bit.202. Sai s thi gian hay sai khong thi gian (TIE):A. Sai s ny tch ly khi mt ngun tn s c s dng nh mt ng h.203. Tn s ti thi im bt k t:A. ft=f0+t204. Sai S Khong Thi Gian (TIE) c nh ngha l:A. lch pha gia tn hiu c o vi tn hiu ng h tham chiu (chun).205. Nguyn nhn gy ra hin tng trt bit:A. Do cc phn t nh thi, s thay i thi gian tr truyn dn, giao thoa gia cc k t, hiu chnh, hot ng ca b ti to xung ng h, mng PDH/SDH (nh x, con tr).206. c im ca jitter do cc phn t nh thi gy ra:A. Bin v tn s tng i thp tc l wander.207. Jitter do chn do:A. Do tnh khng l tng ca b lc thng thp, s dch chuyn in p khng bao gi c lm phng mt cch hon ho.208. nh hng ca jitter (trt bit) vi tn hiu s:A. Tng xc sut li a vo trong tn hiu s, trt khng iu khin c vo tn hiu s (hin tng trn hoc cn b nh).209. i vi cc dch v thoi, slip (trt) ny c th l nguyn nhn gy ra:A. Nhng ting ng nh c th nghe thy.210. Trong truyn fax ch 1 slip gy nn:A. Nhiu hoc mt i 8 dng trong bn fax.211. nh hng ca jitter v wander trong mng SDH:A. Nu jitter ca ti thng tin qu ln, n c th lm trn hoc cn cc b m FIFO.212. Tiu chun rung pha i vi giao din PDH.. 213. Nh gi tr bng.

214. Nh cc gi tr UI ca tng lung PDH lm cc bi ton:.Hay UI=1/tc bit (nh i n v sang bit/s)215. C th tnh chu k khung bng cch ly

216. Tiu chun rung pha v tri pha vi giao din SDH:

217. Yu cu tr khng vo ca my o:A. 75 khng cn bng cho tc 2048kbit/s v 120 cho tc 64kbit/s v 2048kbit/s.218. Mt my phn tch jitter c bn gm:A. Mt b bin i mu/ng h (Pattern/clock converter), b to ng h chun (Internal reference clock generator), b o pha (Phase meter hay Phase detecter), cc b lc trng lng (Weighting filters) v b o gi tr nh (Peak value detecter).219. B to jitter gm:A. Mt ngun ng h, mt ngun jitter v mt b to mu.220. Hai phng php o dung sai jitter : A. Bt u li (onset of error) v pht BER (Ber penalty).221. Quy trnh kim tra bng phng php bt u li nh sau:A. 1. Tng bin jitter ti mt tn s cho trc cho n khi li c ghi nhn. 2.Gim jitter cho n khi khng c ES trong vng 30 giy. 3. Tng dn bin jitter ln cho n khi c 2 ES c ghi nhn trong vng 30 giy. 4. Bin jitter ny chnh l dung sai jitter ti tn s thc hin o. 5. Lp li cc bc 1-3 i vi cc tn s cn li.222. Phng php bt u li c th kim tra:A. Phn ln cc thit b mng, n kim tra c cht lng hot ng ca b m ln mch ti to ng h bn trong phn t mng.223. Phng php pht BER kim tra:A. Cc trm lp giao tip quang. Phng php ny ch kim tra c cht lng ca mch ti to ng h bn trong thit b.224. Quy trnh kim tra bng phng php phtaj BER nh sau :1. Khi khng c jitter u vo, tng dn suy hao quang cho n BER = 10 102. Gim suy hao i ldB.3. Tng dn bin jitter ti mt tn s cho trc cho n khi BER t li gi tr ban u (BER = 10'10).4. Bin jitter ny chnh l dung sai jitter ti tn s thc hin o.5. Lp li bc trn cho tt c cc tn s cn li (trong di tn theo khuyn ngh G.968 ITU).225. y l m hnh o thit b g:

A. o dung sai jitter ca thit b u cui ng dy.226. y l m hnh o thit b g:

A. o dung sai pha ghp knh.227. y l m hnh o thit b g:

A. o dung sai b tch knh.228. y l m hnh o thit b g:

A. M hnh o jitter ni ti/ ng ra.229. y l m hnh o thit b g:

A. . o jitter ni ti ca mt trm lp 34 Mb/s.230. y l m hnh o thit b g:

A. o jitter nh x.231. y l m hnh o thit b g:

A. o jitter con tr tng hp.232. Khi o jitter con tr th thit b o phi c kh nng to ra cc chui con tr:A. n, chum v lien tc.233. Cc chui kim tra con tr c my loi:A. Hai loi: n/chum v u n/chu k.234. Cc chui con tr kim tra gm my giai on:A. 3 giai on: khi ng, lm ngui, o.

CHNG 2. O LI BIT235. Li bit l: A. L s thu sai bit do qu trnh truyn dn tn hiu s trong mng s gy ra.236. T l li bit(BER: Bit Error Rate): A. L t s gia s bit b li trn tng s bit pht i.237. Li khi (EB: Error Block): A. L li mt hay nhiu bit trong mt khi bit.238. Thi gian kh dng: A. L thi gian trong h thng c coi l c kh nng thc hin cc chc nng quy nh.239. Thi gian khng kh dng: A. L thi gian trong h thng c coi l khng c kh nng lm vic.240. Giy b li (ES: Errored Second): A. Mt giy trong khong thi gian kh dng c t l li bit nm trong khong t 0 n 10-3.241. Giy b li nghim trng(SES: Severely Errored Second): A. Mt giy trong khong thi gian kh dng c t l li bit ln hn 10-3 hoc c tn hiu ch th cnh bo AIS.242. Giy b li theo khi (BES: Block Errored Second): A. Trong khong thi gian mt giy c t nht mt khi b li.243. Giy b li nghim trng theo khi (SBES: Severely Block Errored Second): A.Trong khong thi gian mt giy c nhiu hn 30% khi b li hoc c t nht mt ch th cnh bo AIS244. Li khi nn (BBE: Background Block Error): A. Mt khi b li khng thuc trong giy li nghim trng.245. T l li khi nn (BBER: Background Block Error Rate): A. L t s gia li khi nn v tng s khi o c trong khong thi gian kh dng.246. di ca tuyn truyn dn chun gi nh tc 64kbps:A. 27500km vi thi gian o cc thng s li l mt thng.247. 64kbps

248. 3 cp :ni ht, trung bnh, cao (64kbps)

249. (64kbps)

250. Theo khuyn ngh G921 a ra m hnh on s vi cc di thc t tuyn gi nh (2048kbps):A. l 50 hoc 280 km.251. (2048 kbps)

252. Giy b li:

253. Pht suy gim cht lng:

254. Giy b li nghim trng (SES):A. T l phn trm giy b li nghim trng quy chun v u ni ti tc 64kb/s c th c tnh t php o ti tc bit cn o nh sau:SES= Y% + Z%Y: l phn giy b li nghim trng ti tc bit cn oZ: Phn giy khng b li nghim trng nhng cha mt hoc nhiu s mt ng b ti tc bit cn o255.

256. Cc bt bnh thng vi cc lung s PDH:a1: Mt tn hiu ng b khung b lia2: Mt khi b li (EB) c ch th bi m pht hin li (EDC)d1: Mt khung (LOF)d2: Tn hiu ch th cnh bo (AIS)d3: Mt ng b khung.257. Giy b li nghim trng i vi lung PDH:

258.

259. Cc bt thng i vi lung SDH:A. a1: Mt khi b li qua kim tra ca m pht hin li (EDC).260. Cc sai hng dn n SES:

261. Cc thng s v tiu chun o lung SDH:A. ES: Mt giy b li quan st c khi trong mt giy t nht c mt bt bnh thng a1 hoc mt sai hng trong bng trn.SES: Mt giy b li nghim trng quan st c khi trong mt giy t nht c x khi b li hoc mt sai hng trong bng trn.BBE: Mt li khi nn quan st c khi mt bt bnh thng a1 xy ra trong mt khi nhng khng thuc giy b li nghim trng.262. Nhng ngun gy li bn trong h thng:A. Tnh khng n nh ca ng h nhp;ng h nhp b tri;Tnh khng n nh do s lo ha ca cc linh kin;S cn bng khng ng i vi suy hao ng dy ph thuc vo tn s (chng hn trong mt b ti to);263. Mt s nguyn nhn bn ngoi gy ra nhiu:A. Xuyn m (t cc ng dy bn cnh);Trt (tch ly) trong khi truyn dn;Nhiu in t (cc my mc, st,...);Bin ng in p ngun cung cp (chng hn do cc t st gy ra);Nhiu xung (bin nh 5 - 20 mV) ;Nhng bin ng c kh, cc mi tip xc km;S suy gim cc c tnh ca phng tin truyn dn;S c ton b h thng do ng dy b t.264. Cc yu t in hnh nh hng n cht lng truyn dn:

265. Nguyn nhn ca li cm:A. Mt cm li c th do hin tng pha-inh ca sng mang trong truyn dn v tuyn gy ra hoc do nhiu in t ngn (nh chuyn mch) gy ra.266. Nu xy ra mt s dch pha gia cc dng chui bit thu c v tham chiu th my o s cho kt qu:A. S cc li bit o c s l v hn.267. Tiu chun cht lng hin nay l i vi cc kt ni 2 Mbit/s:A. T l li bit nh hn 10-6.268. Phng php o li bit?. 269. FAS l:A. Tn hiu ng chnh khung.270. M ho cc bit SA:

271. Khi o kim tnh nng ca mng SDH cn o kim nhng g:A. Thit b cng, trin khai cc bin th nh x, phn knh v nh x ca cc giao din ni cho hot ng.272. My o li thng s dng trong h thng SDH l:A. ANT-20.273. S sau o thng s g ca SDH:

A. S phn tch nh x (C12,C3,C4).274. My phn tch ANT-20 thc hin cc php o:A. My phn tch s dng s so snh chui bit o o li bit trong phn t tin chui bit gi ngu nhin (PRBS) v nh gi nhng di chuyn ca con tr ca TU-12 v AU-4.275. Cu trc ca 1 khung SMT-1 gm bao nhiu lung 2Mbit/s:A. STM-1 cha 63 cng-ten-n, mi cng-ten-n mang mt tn hiu 2 Mbit/s.276. S sau l s :

A. Kim tra cc giao din cng 2 Mbit/s cso i ni ng hay khng.277. S sau l s :

A. Php o s dng tn hiu c cu trc.

278. S sau l s :

A. o kim hot ng chuyn mch cc dch v phn b279. S sau l s :

A. Php o trn cc b ghp knh xen r.280. Ngoi ra khi o li bit trn h thng SDH cn o cc thng s : o li bit DCC/ECC; o tr; chuyn mch bo v t ng; o hot ng ca con tr.281. DCC/ECC l:A. Knh thng tin s liu/Knh thng tin gn lin.

CHNG 1. TNG QUAN V MNG VIN THNG V CC PHP O TRONG VIN THNG282. Mng vin thng l:A. Mng thc hin truyn a thng tin t u pht ti u thu nhm cung cp cc dch v vin thng cho khch hng.283. Mng vin thng bao gm cc thnh phn chnh: A. Thit b chuyn mch, thit b truyn dn, mi trng truyn v thit b u cui.284. Chc nng ca thit b u cui:A. Gip cho vic giao tip gia mng v con ngi hoc my, bao gm c cc my tnh. Thit b u cui chuyn thng tin thnh cc tn hiu in v trao i cc tn hiu iu khin vi mng.285. Chc nng ca cc thit b chuyn mch l:A. Thit lp cc ng truyn.286. Chc nng chnh ca tng i:A. Xc nh thu bao - Kt ni vi thu bao b gi - Phc hi (gii phong cuc gi) h thng khi cuc gi kt thc.- Tnh cc cuc gi.287. Nhim v ca tng i:A. Bo hiu, X l thng tin bo hiu v iu khin thao tc chuyn mch, Tnh cc.288. Chc nng ca bo hiu:A. L nhim v trao i vi cc thit b bn ngoi tng i gm cc mch in v cc ng dy thu bao, cc trung k u ni n thu bao hay n tng i khc.289. Chc nng ca x l thng tin bo hiu v iu khin thao tc chuyn mch: A. Thit b iu khin chuyn mch s nhn thng tin bo hiu t ng dy thu bao v trung kB. X l cc thng tin bo hiu v a cc thng tin iu khin cp tn hiu n ng dy thu bao, trung k v cc thit b ngoi vi khc iu khin thc hin cng vic chuyn mch, thng bo u ni, gim st v gii phng kt ni.C. C A v B 290. Chc nng ca thit b truyn dn:A. Thit b truyn dn c s dng ni cc thit b u cui hay gia cc tng i vi nhau v truyn cc tn hiu mt cch nhanh chng v chnh xc.291. Phn loi thit b truyn dn:A. Thit b truyn thu bao (ni thit b u cui vi mt tng i ni ht) v thit b truyn dn chuyn tip (ni gia cc tng i).

292. Thit b truyn dn thu bao c th s dng:A. Cp kim loi hoc radio, cp quang (s dng cho ng thu bao ring v ISDN).293. Thit b truyn dn chuyn tip s dng :A. Cc h thng cp si quang, h thng vi ba, h thng v tinh v.v294. Cu trc mng vin thng ca VNPT hin nay c chia thnh:A. 3 cp: cp quc t, cp quc gia, cp ni tnh/ thnh ph.295. Xt v kha cnh chc nng ca cc h thng thit b trn mng th mng vin thng bao gm: A. Mng chuyn mch, mng truy nhp, mng truyn dn, v cc mng chc nng.296. Mng chuyn mch c my cp (da trn cc cp tng i chuyn mch): A. 4 cp :qu giang quc t, qu giang ng di, ni tnh v ni ht.297. Mng chuyn mch thnh ph H Ch Minh c my cp (da trn cc cp tng i chuyn mch):A. 5 cp :qu giang quc t, qu giang ng di, ni tnh, ni ht, qu giang ni ht.298. Mng ca VNPT c cc trung tm chuyn mch quc t v chuyn mch quc gia :A. H Ni, Nng, Thnh ph H Ch Minh..299. Mng vin thng ca VNPT hin ti c chia thnh my cp:A. 5 cp trong tng lai s c gim t 5 cp xung 4 cp.300. Mng thnh vin ca VNPT iu hnh: A. l VTI, VTN v cc Bu in tnh.301. VTI c ch nng:A. Qun l cc tng i chuyn mch qu giang quc t. 302. VTN c chc nng: A. Qun l cc tng i chuyn mch qu giang ng di ti 3 trung tm H ni, Nng v Tp H Ch Minh. 303. Cc loi tng i c trn mng vin thng Vit Nam: A. A1000E10 ca Alcatel, NEAX 61 ca NEC, AXE10 ca Ercsson, EWSD ca Siemens.304. Cc cng ngh chuyn mch c s dng: A. Chuyn mch knh (PSTN), X.25 relay, ATM (s liu).305. V tr ca mng truy cp:A. Mng nm gia ngi s dng dch v vin thng v im dch v ca mng (tng i).306. Mng truy nhp hin nay gm cc loi:A. Mng cp kim loi, cp chn, cp treo, cp cng - Mng cp quang - Mng v tuyn.- H thng VISAT (Very Small Aperture Terminal).307. Cc h thng thit b truyn dn trn mng vin thng ca VNPT hin nay ch yu s dng loi cng ngh l: A. Cp quang SDH v vi ba PDH.308. Cc thit b ca cp quang SDH c dung lng:A. 155Mb/s, 622Mb/s, 2,5Gb/s,10Gb/s.309. Thit b PDH c ngun gc t cc hng cung cp:A. Siemens, Fujitsu, Alcatel, SIS, SAT, NOKIA, AWA.310. Mng truyn dn c my cp: A. Mng truyn dn lin tnh v mng truyn dn ni tnh.311. Mng truyn dn ng trc quc gia ni gia H Ni v Tp H Ch Minh c chiu di:A. 4000 km, s dng STM -16/ 2F BSHR.312.Vng 1 ca mng truyn dn quc gia:A. H Ni H Tnh (884Km).313. Vng 2 ca mng truyn dn quc gia:A. H Tnh - nng (834Km).314. Vng 3 ca mng truyn dn quc gia:A. Quy Nhn Tp H Ch Minh (1424Km).315. Mng truyn dn lin tnh bng v tuyn dng h thng vi ba SDH:A. (STM-1, dung lng 155Mb/s: tuyn Bi Chy Hn Gai).316. Mng truyn dn lin tnh bng v tuyn dng h thng vi ba PDH A. (dung lng 4Mb/s, 8Mb/s, 34Mb/s, 140Mb/s) trn cc truyn khc.317. Tuyn truyn dn ni tnh s dng:A. 88% s dng h thng vi ba v h thng truyn dn quang.318. Hin nay trn mng vin thng Vit nam s dng c hai loi bo hiu:A. R2 v SS7.319. Bo hiu cho PSTN:A. R2 v SS7.320. Bo hiu i vi mng truyn s liu qua IP:A. H.323.321. Bo hiu i vi ISDN:A. Bo hiu knh D.Q.931.322. Cc ng h ng b ca Vit Nam c b tr nh th no:A. 3 ng h ch PRC ti H Ni, Nng, thnh ph H Ch Minh v mt ng h th cp SSU.323. Mng ng b Vit Nam c my cp:A. 4 cp (cp 0- cp 4).323. c im cu su suy gim v mo dng: A. S suy gim s l hm ca tn s.324. Cc yu t nh hng n cht lng mng vin thng:A. Suy gim v dn n mo dng - lm chm - nhiu. 325. Cc loi nhiu nh hng n cht lng mng vin thng:A. Nhiu nhit - Tp m ni b - Xuyn m - Nhiu xung. 326. Cng thc tnh nhiu nhit:A. N = kTB. Trong B l bng thng c th k hiu B l W.327. Nhiu do hin tng phch sinh ra do:A. Hin tng khng tuyn tnh trong cc thit b pht, thu, h thng truyn ...328. c im ca nhiu xung:A. L loi nhiu khng lin tc, khng quy lut nhiu khi n l nhng t bin bin ln, trong thi gian nh. 329. Nhiu sinh ra do nhiu nguyn nhn:A. t bin in t trng, nh sng, tt bt h thng my ...320. Quy trnh o theo cc giai on: (cu hi cha st lm nhng tm hiu)A. Sn xut Lp t - Khc phc s c, bo dng - Sa cha/Xc nh qui m.321. Yu cu khi o trong sn xut:A. Tc o c ti a ha, so snh nhanh cc gi tr danh nh v gi tr thc t, iu khin t xa, tch hp vo cc h thng o th t ng.322. Yu cu khi o trong lp t:A. Phn tch lc u v phn tch trong thi gian di, Cc php o c thc hin khi thit b khng cung cp dch v, cc qui trnh/tin trnh o c nh trc, lu tr kt qu o, phn tch lu di, d dng s dng, c th mang i c v mnh.

323. Yu cu khi o trong khc phc s c, bo dng:A. Cc php o khi thit b ang cung cp dch v (in-service) hoc khng cung cp dch v (out-ofservice), gim st ng dy v thuc tnh, m phng li v cc cnh bo.324. c im khi o trong sa cha:A. Xc nh v tr s c mc bng mch in, m phng cc iu kin hot ng.MT S NI DUNG CN CH 1. Cc thut ng:

1 lung STM1 c th ghp t: Ghp mt lung nhnh 139,264 Mbit/s; Ghp 3 lung nhnh 34,368 Mbit/s; Ghp 63 lung nhnh 2,048 Mbit/s; Ghp 1 lung nhnh 34,368 Mbit/s v 42 lung nhnh 2,048 Mbit/s; Ghp 2 lung nhnh 34,368 Mbit/s v 21 lung nhnh 2,048 Mbit/