Thit b viba s RMD 904 - Nhm 5 K thut viba s N05

Thit b viba s RMD 904 - Nhm 5 K thut viba s N05

TRNG I HC CNG NGH THNG TIN & TRUYN THNGKHOA CNG NGH IN T & TRUYN THNG----------

BO CO MN K THUT VIBA S ti: Thit b viba s RMD 904Ging vin: Phm Vn NgcLp: K thut viba s N05 Nhm thc hin: 1. Trn Vn Bn2. Phm Hng Hin3. Dip Thu Huyn4. L Xun Ha5. Nguyn Mnh Linh6. ng Thanh Lun

Thi Nguyn, thng 10 nm 20121

MC LC

1. Gii thiu chung RMD 90432. Ch tiu k thut ca h thng RMD 90443. iu ch trong thit b vi ba s RMD 90454. My pht RMD 90464.1. Khi x l bng tn c s pht TxBaseband74.1.1. Khi bng tn c s pht chnh74.1.2. Khi bng tn c s ph pht84.1.3. B khuch i logarit v mch cnh bo94.1.4. B cp ngun mt chiu104.2. Khi kch thch114.2.1. Khi iu ch OQPSK114.2.2. B tng hp tn s124.3. Khi khuch i cng sut134.4. Khi hin th145. My thu RMD 904145.1. Khi bin i h tn155.1.1. B bin i h tn v tuyn155.1.2. B tng hp tn s165.2. Khi trung tn thu165.3. Khi bng tn c s thu175.3.1. Khi x l bng tn c s chnh175.3.2. Khi bng tn c s ph195.3.3. Khi cp ngun196. ng dng:19

THIT B VIBA S RMD 904

1. Gii thiu chung RMD 904Hng AWA sn xut cc h thng viba s lm vic cc bng tn 900MHz, 1500MHz v 1800MHz. Cc thit b v tuyn viba s ca hng ny s dng phng thc iu ch pha vung gc QPSK. H thng cho php truyn dn cc lung 2Mb/s, 22Mb/s v 42Mb/s s dng m ng HDB3 mc cng sut +37dBm (5Wat).Cu trc Modul ca thit b cho php d dng bo qun v sa cha.Cc thit b viba s ny c th c s dng t chc cc tuyn n hay nhiu trm cho thng tin ng trc hoc ng nhnh. C th t chc chng theo cu hnh truyn dn khng d phng vi mt my pht v my thu tng pha. Cng c th t chc chng dng truyn dn c d phng t c tin cy cao hn. Tn ti ccphng thc d phng sau y thit b: D phng m, d phng nng, phn tp tn s,phn tp khng gian. trm c d phng khi xy ra s c th my thu v my pht d phng c chuyn mch bo v (Protecttion Switch) chuyn vo ch cngtc.Thit b viba s RMD-904 c sn xut bi AWA s dng trong cc h thng viba s lm vic cc bng tn hp t 820 MHz - 960 MHz. RMD 904 l thit b viba s u tin c a vo lp t khai thc trn mng truyn dn viba s nc ta. Hin nay th hu ht cc tnh, huyn trong c nc u ang s dng, khai thc thit b ny.

Hnh 1: S khi thit b thu pht RMD 9042. Ch tiu k thut ca h thng RMD 904 Dung lng: 60 knh thoi (22Mb/s). Bng tn v tuyn: 820 MHz960 MHz. Cng sut ra ch u anten: +37 dBm. Ngng thu: -90 dBm. iu ch tn hiu s: OQPSK. u vo s liu: HDB3 2,048 Mbit/s, 75 khng cn bng. iu ch knh nghip v: FM. Di tn knh nghip v: 15kHz. p tuyn tn s knh nghip v 3002200 Hz : +2dB 3 dB. Mc vo knh nghip v (600): 0dBm. Mc ra knh nghip v (600): 0dBm. T s tn hiu / tp m: >40dB (dBm op/chng). Tn s tone gi: 2,0 kHz. iu ch knh gim st: FM. Di tn knh gim st: 5 kHz/tone. p tuyn tn s knh gim st 2,7 kHz5,0 kHz : + 2 dB 3dB. Mc vo knh gim st (600):-10dBm. Mc ra knh gim st (600):-10dBm. Ngun cung cp: in p mt chiu DC : -24 V hoc -48 V. Cng sut tiu th ton b trn mt my u cui: Vi cng sut ra 5W: 63W. Vi cng sut ra 1W: 43W. H thng vi ba c cc phng php d phng: D phng m (warm standby). D phng nng (hot standby). Phn tp tn s (frequency diverity). Phn tp khng gian (space diversity). thchinbov,trm viba c d phng clpb chuynmchbov (protection switch). Thit b thu pht lm vic vi phi l cp ng trc trkhng 50. Ty theo iu kin thc t yu cu, thit b viba lm vic vi anten parabol ng knh: 0,9m; 1,2m; 1,8m; 2,4m.3. iu ch trong thit b vi ba s RMD 904My thu pht viba s s dng kiu iu ch s OQPSK iu ch pha 4 trng thi m ha trc tip (Offset Quadrature Phase Shif Keying).B iu ch OQPSK c gi l iu ch pha cu phng. Mi mt lung s liu c x l bng mch iu khin, hn ch mc v i qua b lc thng thp. Hai lung s liu ny c a vo hai b trn cn bng vi tn s sng mang trung tn IF 220MHz iu ch 2PSK ca hai nhnh, c a vo b cng kt hp hai tn hiu ca hai b trn s to c ra tn hiu OQPSK. Tn hiu sng mang tn s 220MHz c ly t b dao ng thch anh 73,333MHz v c nhn ba (bi tn bc 3).B chuyn i m t n cc sang lng cc (m NRZ) vi bin 0,7V do haiDoide trong mch 9V4 (9V3) vi c hai lung s hiu A v lung s hiu B. Sau cc lung s ny i qua mng RC gim chm cc sn xung sao cho t s y c th iu chnh tht bng nhau u ra ca b bin i m.Hai tn hiu sng mang 220MHz c cn bng bng cch iu chnh mc 1 chiu (DC) trong 2 b trn c s dng iu chnh b trong b khuch i 9N2 v 9N3. Tc l ln lt iu chnh cc chit p 9R57 v 9R58. ng thi mt trong hai tn hiu sng mang 220MHz c a qua b lch pha 90 sau mi c a vo b iu ch pha: 2PSK. Tn hiu ra ca mi b iu khin 2PSK c tn s 220MHz v pha lch nhau 90 ri tip tc a qua b tng hp (trn hai sng mang c iu ch ny vi nhau). u ra ca n s thu c tn hiu sng mang IF 220MHz v c iu ch pha cu phng OQPSK a qua b khuch i tuyn tnh tn hiu sng mang ny c khuch i v bin in p a sang b trn nng tn.4. My pht RMD 904

Hnh 2:S khi my pht RMD 904My pht RMD 904 gm cc khi chnh: Khi x l bng tn c s pht TxBB (Transmitter Base Band). Khi kch thch (Exciter). Khi khuch i cng sut pht PA: Power Amplifier. Khi hin th my pht Tx Dislay.Cc ch tiu k thut ca my pht RMD 904: Cng sut ra: +37dBm. Tr khng ra: 50. n nh tn s: +15ppm. Bc nhy tn s: 100KHz. Nhiu pht ra: