OBJECTIVES 1. GENERAL. Printed in U.S.A. Page 1. SECTION Issue 1, January AT&TXe Standard PAGE CONTENTS GENERAL...

Transcription

1 BELL SYSTEM AT&TXe Stndrd PRACTCES SECTO sse 1, Jnry 1976 RADO EGEERG MCROWAVE RADO C/l OBJECTVES 11-GHZ SYSTEMS COTETS PAGE GEERAL GHZ RADO SYSTEMS of both received signls. t cn be ssed tht systes hich hve chrcteristics siilr to those given in Tble A ill hve siilr spectrl densities, ith the reslting C/ objectives nd interference spectr siilr to those shon in this section BASEBAD TERFERECE SPECTRA.. 2 C/l OBJECTVES GEERAL 1.1 This section contins the crrier-to-interference (C/1) objectives for 11-GH Microve Rdio Systes. Also inclded re the bsebnd interference spectr fro hich the C/ objectives re derived. 1.2 Whenever this section is reissed, the reson for reisse ill be listed in this prgrph. 1.3 The C/ objectives re clclted for the TL-2 nd T-1 systes; hoever, the objectives cn be sed for other rdio systes hich hve chrcteristics siilr to those specified in this section. 1.4 Refer to Section for instrctions regrding the interprettion of the dt contined in this section nd for the reltionship beteen the bsebnd interference spectr nd the tblted C/ objectives GHZ RADO SYSTEMS 2.1 The chrcteristics of the TL-2 nd the T-1 rdio systes ere sed in the clcltion of the 11-GH C/ objectives. These chrcteristics re shon in Tble A. All of the preters re sed to clclte the bsebnd interference spectr 2.o2 The TL2 nd T-1 systes considered here re identified by their circit lodings; for exple, T-1(12) designtes T-1 syste ith 12-circit loding, nd T-1 (TV) designtes T-1 syste crrying television video signl, ith or ithot diplexed dio. Additionlly, the 6-chnnel lodings re differentited ccording to the to types of ltiplex in coon se; ths, TL2(U6) nd TL2(L6) designte, respectively, TL-2 syste crrying U6 ltiplex nd one crrying L6 ltiplex. All other voice-circit lodings re ssed to be U6 derived circits. Finlly, T-1(18*) designtes n 18-circit T-1 syste hving redced devition. 2.3 All clcltions ere perfored ssing CCR pre-ephsis. Althogh the clcltions re reltively insensitive to the type of pre-ephsis sed, this ssption does fcilitte coordintion ith other crriers nd llos ore niversl pproch to verifiction otside the Bell Syste. 2.4 The chrcteristics of syste crrying TV is oitted fro Tble A becse the spectr of TV signl does not lend itself to clcltion, nd the preters sed to describe essge service re not sitble for describing TV signls. Conseqently, the esred spectr of n FM signl odlted by the Girl in Str Ht color pictre is sed. The lo-index FM signl ses 226L pre-ephsis nd contins silted diplexed-dio signl t 6.2 MH djsted to 12 db reltive to the O-dBV TLP. OTCE ot for se or disclosre otside the Bell Syste except nder ritten greeent Printed in U.S.A. Pge 1

2 SECTO TABLE A 11-GH RADO SYSTEM CHARACTERSTCS RADO SYSTEM TYPE CHAEL CAPACTY (CKTS) TOP BOTTOM TOTAL RMS PER CKT BASEBAD BASEBAD FREQUECY ( dbo) FREQUECY FREQUECY DEVATO DEVATO (MH ) (MH) (kh) (kh) FREQUECY PRE- STABLTY EMPHASS (%) TYPE TL-2(U6) CCR TL-2(L6) 6 2,788, CCR TL-2(12) CCR T-1(12) CCR T-1(18) CCR T-1(18*) CCR T-1(24) CCR ote: T-1(18* ) hs redced devition for interconnecting T-1 nd TH The <Girl in Str Ht color pictre s chosen s n verge, rther thn orst-cse, signl on the bsis of spectr shpe nd pek devition. The se of different TV signl old l)rodce different poer density spectr nd, conseqently, different C/ objectives. 3. BASEBAD TERFERECE SPECTRA 3.1 Bsebnd interference spectr fro ll cobintions of 11-GH systes re presented in Fig. 1 throgh 28. The odd-nbered figres present the interference spectr fro the collective TL2 systes into individl TL2 nd T-1 systes, nd the e~,en-nbered figres present the interference spectr fro the collective T-1 systes into individl TL-2 nd T-1 systes. Frther, Fig. 1 throgh 14 re for cochnnel interference, nd Fig. 15 throgh 28 re for interference fro n djcent (2-MH y) chnnel. Bsebnd spectr for interference into TV re not given becse only single video chnnels re involved, nd the interference t prticlr freqency in video chnnel is of little significnce. For convenience, the interference spectr re clclted for norlied interference signls (the interfering signl is ssed eql in strength to the desired signl). This is eqivlent to hving ero RF sppression (C/ =) nd provides sefl strting point for C/ objective clcltions. 3.2 Ech interference spectr crve s clclted for the orst-cse freqency seprtion lloed by the freqency stbility of both crriers. For cochnnel essge service, orst-cse freqency seprtion occrs hen the freqency difference is eql to the top bsebnd freqency of the desired signl; for other freqency differences, the interference decreses. f the xi freqency seprtion is less thn the top bsebnd freqency, s is the cse ith systes hving ore stble crriers nd greter essge cpcities, the crves reflect the interference t xi lloble seprtion. Mxi freqency seprtion is deterined fro the freqency tolernce vles in Tble A. Ths, for TL-2/TT-l cobintion, the xi freqency seprtion is 5.72 MH (11 GH X GH X.2%). For sch cobintion nd ith the desired syste being T-1(18), the orst-cse sidebnd interference occrs t 5.72 MH, hich is ithin the MH top bsebnd freqency. Mxi freqency seprtion for TL-2/TL-2 cobintion is 11 MH nd.44 MH for T-1/T-l cobintion. For the TL-2/TL-2 cobintion, the xi top bsebnd freqency ith 12-chnnel loding is MH. Hence, the clcltions re perfored Pge 2

3 1SS 1, SECTO t tht seprtion. For interference fro syste crrying TV service, xi interference occrs t freqency seprtion tht is less thn the top bsebnd freqency nd is dependent on the poer distribtion of the interfering TV signl t specific instnt. (See 2.5.) 3.o3 n the cochnnel bsebnd interference spectr, the continos, or sidebnd, interference is the reslt of the interction of the desired crrier nd the interfering sidebnds nd the interction of the desired sidebnds nd the interfering crrier. When the totl instbility of the to systes kes possible freqency difference in the to crriers tht exceeds the botto bsebnd freqency of the desired syste, crrier bet y occr in tht bsebnd. This does not en tht crrier bets re not possible ith ore stble systes nd/or higher botto bsebnd freqencies. Hoever, the ssption is de tht the probbility of inbnd bets on sch rotes is negligibly sll, nd ths the crrier bet is not sed s bsis for coordintion. 3.o4 On the bsebnd interference spectr plots, crrier bets re grphiclly represented by verticl spike. The spikes re plced t the highest bsebnd freqency lloed by the noinl freqency instbilities of the to systes, or t the top bsebnd freqency if the totl instbility is greter thn the top bsebnd freqency, (The xi interference increses ith freqency seprtion p to seprtion eql to the top bsebnd freqency; hoever, the xi interference does not necessrily fll t the top bsebnd freqency. n prctice, the crrier bet for ost systes ill not be pre tone bt ill contin soe jitter. For this reson, the interference level of the spike incldes 1-dB brble fctor redction. For systes tht cn not inherently jstify this redction, it is ssed tht n intentionl brble hs been introdced throgh the se of crrier spreding circit. See Section for the ppliction of this fctor. 3.o5 n the djcent-chnnel (2-MH spcing) interference spectr, the interference is de lost entirely to sidebnd overlp. And since the overlp occrs fro the higher-order sidebnds here the poer levels re loer, the interference is loer; this is reflected in the bsebnd interference spectr. Like the cochnnel interference, the dj scent-chnnel interference is deterined for orst-cse freqency seprtion sing the freqency tolernce vles fro Tble A. Unlike the cochnnel cses, orst-cse djcent chnnel seprtion is the ini freqency seprtion. Ths, orst-cse seprtion for djcent chnnel opertion of T-1/TL-2 cobintion is MH (2-5.72). Siilrly, for T-1/T-l nd TL-2/TL-2 cobintions, the orst-cse seprtions re, respectively, MH nd 9. MH. 3.6 n the cochnnel spectr for interference fro syste crrying TV service, crrier bets re not present becse the TV-FM spectr does not contin crrier. The interference is csed by interction beteen the TV sidebnds nd the crrier nd sidebnds of the desired syste; except for systes ith L6 ltiplex, the interference fro TV service syste is greter thn tht fro essge-service syste becse TV-FM sidebnd energy is greter ner the crrier freqency. 4. c/1 OBJECTVES 4.o1 Tbles B nd C contin the ini C/ objectives necessry to eet the bsebnd noise objectives. For high noise, lo stbility syste (forerly tered short hl) sch s TL-2, the noise objective is 14 dbrnco per exposre in 4-kH chnnel for both crrier bet nd continos interference. For lo noise, high stbility syste sch s T-1, the crrier bet objective is 17 dbrnco per exposre for crrier bet nd 4 dbrnco per exposre for continos interference. ote tht becse T-1 hs the noise perfornce per hop nd high stbility coon to systes in the long hl netork nd y be sed in the long hl netork, the syste reqires the se protection fro interference s does long hl rdio syste. The entries in Tbles B nd C express in db the totl isoltion (the rtio of the desired signl to the interfering signl t the inpt of the desired receiver) necessry to chieve the noise objective. Section describes ore flly the se of these objective tbles s ell s djstents hich cn be de for specific sittions. 4.2 Tble B contins the objectives for cochnnel opertion. When crrier bets re possible, the tble trix eleent contins three entries. The top nd iddle enteries re, respectively, the reqired isoltion (1) hen both crriers re nodlted nd (2) hen both re odlted; the botto entry is the reqired isoltion hen no crrier bet is present nd is bsed on continos Pge 3

4 SECTO TABLE B TERFERECE OBJECTVES (C/1) 11-GH BAD COCHAEL AALOG SYSTEMS. TERFERG CARRER TL-2 TL-2 TL.2 T-1 T.1 T-1 T.1 TL.2 T-1 (U6) (L6) (12) (12) (18) (18 ) (24) (TV) (TV) TL-2 (U6) TL-2 (L6) TL-2 (12) K E K o K.7 U2 o T.1 (12) T.1 (18) T.1 (18 ) T.1 (24) TL-2 (TV) T.1 (TV) ~,Yot( : C/l vles for interference into TL-2 systes bsed on 14 dbrnco per exposre noise contribtion. C/1 vles for interference into T-1 systes bsed on 4 dbrnco per exposre for crrier-sidebnd nd 17 dbrnco for crrier-bet. TL-2 Trnsitter Type (L!6) _ Voice Circit Loding or TV Signl 78 _ C/ ith both crriers nodlted (db) 73 C/ ith both crriers odlted (db) 58 _ C/ ith crrier-sidebnd interference (db) Pge 4

5 1SS 1, SECTO interference only. Both crrier bet entries sse sfficient crrier jitter to llo the se of the brble fctor entioned in 3.4. Therefore, if both crriers re inherently very pre nd if neither re odlted by crrier spreding circits, both crrier-bet objectives st be incresed by 1 db. 4.o3 The differences beeen the nodlted nd the odlted crrier-bet interference for the vrios interfering/desired-crrier cobintions rnge fro s little s 1 db to s ch s 17 db, s is indicted by the corresponding C/ entries in Tble B. When the difference is insignificnt (2 db or less), it is prcticl to se the nodlted C/ objective. Hoever, hen the difference is greter, n objective hlf-y beteen the to entries is recoended. This is becse the nodlted-crrier objective is ore stringent thn is slly necessry, nd the se of the odlted-crrier objective reqires fll odltion on the interfering crrier. 4.o4 An exception to the hlf-y recoendtion is n interference sittion in hich L6 ltiplex is sed. Where the desired syste ses L6 ltiplex, the iddle entry (odlted crrier bet) shold be incresed by 2. db nd sed s the crrier-bet objective. When the interfering syste ses L6 ltiplex, the top entry (nodlted crrier bet) shold be decresed by 2. db. When both systes se L6 ltiplex, the iddle entry pls 2. db shold be sed. (L6 is the desired syste.) 4.o5 Tble C contins the objectives for djcent-chnnel opertion (2-MH seprtion). Since crrier bets re not predicted by the chrcteristics of the systes considered here, Tble C does not contin ny sch objectives. Also, since the bsic clcltions sed to derive these objectives yield nrelisticlly lo vles for soe dj scent-chnnel cses, Tble C incldes dditionl vles hich hve been djsted for eqipent considertions sch s AGC cptre or threshold degrdtion. The C/ vle of 4 db is necessry to prevent AGC cptre of n interfering signl by TL-2 syste in deep fde. The C/ objective of 56 db is sed to prevent the phenoenon of threshold degrdtion on T-1 syste in deep fde. An interfering syste 2 MH y fro T-1 chnnel reqires the threshold degrdtion objective to be the fde rgin (ssed to be 5 db) pls 6 db. f loer or higher fde rgin is expected on prticlr hop of T-1, this nber y be djsted. f the fde rgin ere 45 db, the C/ vle old be = 51 db. The nber y be djsted donrd to the clclted C/ vle (botto figre in Tble C) if the fde rgin is sfficiently lo. This threshold degrdtion nber y be frther redced by 1 db if 2-MH filter (142A) is sed on the desired T-1 chnnel. The filter sfficiently ttentes FM nlog essge or TV interference 2 MH y. The 1-dB redction y not be sed if the interfering signl ses digitl odltion. The 2-MH clclted C/ vles (rther thn the threshold degrdtion vles) y be sed to evlte interference beteen T-1 chnnels on the se hop. 4.6 For 4-MH seprtion, the C/ objective is 2 db for ny interfering syste into ny desired syste except TV. An interfering syste into TV t 4-MH seprtion reqires C/ objective of 35 db. These re lso eqipent (not directly clclted interference) relted nbers. JVote: For ost recent chnges to C/ vles conslt Long Lines Hedqrters Freqency Coordintion Grop. Pge 5

6 1 SECTO TABLE C TERFERECE OBJECTVES (C/1) 11-GH BAD 2-MH SEPARATO AALOG SYSTEMS TERFERG CARRER TL-2 TL-2 TL-2 T-1 T-1 T-1 T-1 TL-2 T-1 (U6) (L6) (12) (12) (18) (18 ) (24) (TV) (TV) TL-2 (U6) 4/37 4/35 4/36 4/16 4/14 4/21 4/33 4/37 4/11 TL-2 (L6) 4/34 4/3 4/36 4/14 4/23 4/19 4/35 4/37 4/9 TL-2 (12) / /3 T-1 (12) 56/47 56/44 56/45 56/23 56/37 56/32 56/39 56/41 56/2 T-1 [18) /45 56/46 56/ /4 T-1 (18*) /45 56/47 56/ /4 T-1 (24) TL-2 (TV) 4/23 4/22 4/36 4/2 4/21 4/2 4/33 4/35 4/35 T-1 (TV) 56/2 56/2 56/2 56/2 56/2 56/2 56/2 56/35 56/2 ote: C/ vles for interference into TL-2 systes bsed on 14 dbrnco per exposre noise contribtion. C/ vles for interference into T-1 systes bsed on 4 dbrnco per exposre noise contribtion. +-Trnsitter Type Voice Circit Loding or TV Signl 4/16 C/ for 2-MH seprtion 1. ToP Figre Adjsted for eqipent liittion (db): AGC c~ptre for-interference-into TL-2 Threshold degrdtion for interference into T- 2. Botto Figre Copted C/ nber (db) 3. Single Figre Copted C/ nber (db) Pge 6

7 1SS 1, SECTO , U. 1- Z n i < , 3.5 4, BASEBAD FREQECY - MHZ Fig. l Bsebnd Spectr Cochnnel nterference Fro TL-2 nto TL-2(U6) Pge 7

8 SECTO v <? BASEBAO FREQUECY - MHZ Fig. 2 Bsebnd Spectr Cochnnel nterference Fr T-1 nto TL-2(U6) Pge 8 1,

9 1SS 1, SECTO %1 A L 1- Z : n 1.5, , BASEBAO FREQUECY - MHZ Fig. 3-Bsebnd Spectr-Cochnnel nterference Fro 11-2 nto TL-2(L6) Pge 9

10 SECTO ! v. L- Z (n L BASEBAD FREQECY - MHZ Fig. 4-Bsebnd Spectr Cchnnel nterference Fro T-1 nto TL-2(L6) Pge 1

11 1SS 1, SECTO : 11 KEY. TL-2 (U6) 5 TL-2 (L6) _ TL-2 (121 1 TL-2 (TV) TL -2 (U6, L6, 12) [UMOO]i (12) [MOD] # o d : cc r A BASEBAD FREQECY - MHZ Fig. 5 Bsebnd Spectr Cchnnei nterference Fro TL-2 nto TL-2(12) Pge 11

12 i SECTO s 1 KEY: T-1 (12) T- (EOO) 5 T- (18H) _ : T-1(24) ~ T-1 (ALL) ~ 1 - T- (TV) ~ P -, g 8 A,1 n 75 /. i L+HAAEk 6 55 L 1 k ( A ! 1 1 T [ i 1 [ 1 1?$ ) 45 ~ BASEBAD FREQUECY - MHZ Fig. 6-Bsebnd Spectr-Cochnnei interference Fro T-l into TL-2(12) Pge 12

13 1ss 1, SECTO KEY: TL-2 (U6) 5 TL-2(L6) _ 1 TL-2 (12) TL-2 (TV) TL-2 (U6, L6, 12). UMOO] TL-2 (U6) [MOD] 95 - i 1 TL-2 (L6) [MOO], h 9 85 ti t / /~ ~ \, \ 8 / i \ 75 - A d 7 / 65 6 P r BASEBAD FREQUECY - MHZ Fig. 7 Bsebnd SBectr Cochnnei nterference Fro TL-2 nt T-1.. ( 12}

14 i SECTO T-1(18) _ 1 T-1(24) _ 95 T- 1( TV) _ X- Y id 7 65 r BASEBAD FREQUECY - MHZ Fig. 8 Bsebnd Spectr Cochnnel nterference Fro T-1 nto T-1 ( 12) Pge 14

15 1SS 1, SECTO t O 95 9 E L 1-85 Z 4 LJ n 75 n 7 L s 65 E BASE13AD FREQUECY - MHZ Fig. 9 Bsebnd Spectr Cchnnel nterference Fro TL-2 nto T-1 ( 18) Pge 15

16 SECTO n 95 v :. 9 E + 85 U 8 75 o 7 ; s =, -o e 9 1 BASEBAD FREQECY - MHZ Fig. 1-Bsebnd Spectr Cochnnel nterference Fro T-1 nto T-1 (18) Pge 16 b

17 , 1SS 1, SECTO o 15 l 95 : 2W. k 85 ~ o ~ i d %65 E o BASEBAD FREQUECY - MHZ Fig. 1l Bsebnd Spectr Cochnnel nterference Fro TL-? nto T-1 ( 18 ) Pge 17

18 SECTO , o 1 id v. + W < o d ; E BASEBAD FREQUECY - MHZ Fig. 12 Bsebnd Spectr Cochnnel interference Fro T-1 nto T-1(1 8 ) * Pge 18 r

19 1SS 1, SECTO KEY: TL -2 (6, L6, 121 [MOO1,TL-2 (12) [McQ 4 TL-2 (6) 15 - g 1 o TL-2(6) [MOO] TL-2(L6) [MOD], L TL-2(L6) = TL-2 (12) TL-2 (TV) : : 1, ; 9 + A. + & 85 \ _ 5! 8 \ >. : 75 L? //- : 7 ; 65 X. / / E 6 55 / BASEBAD FREQECY - MHZ Fig. 1&Bsebnd Spectr Cochnnel nterference Fro TL-2 nto T-1 (24) Pge 19

20 SECTO KEY: T-1 (lzoo) o 1.. L T-1(18) _ T (EOOM) _ T-1 [24) _ T- (TV) ~. E c1 < o 8! 75 7 hi ; < , 1; ~, BASEBAO FREQUECY - MHZ Fig. 14 Bsebnd Spectr Cochnnel nterference Fro T-1 nto T-1 (24) Pge 2 i

21 1SS 1, SECTO : E 45 L 1-4 c1 35 < 3 25 J 2 2 E , BASEBAD FREQUECY - MHZ Fig. 15 Bsebnd Spectr Adicent Chnnel nterference Fro TL-2 nto TL-2(U6) Pge 21

22 SECTO c1 5 c1 45 L k < Y Z BASEBAO FREOUECY - MHZ Fig. 16-Bsebnd Spectr Adicent Chnnel nterference Fro T-1 nto TL-2(U6) Pge 22,

23 .. 1SS 1, SECTO i-l 55 n 3 e 45. e 1-4 : 35 : 3 c1 % 25 J 2 K , BASEBAD FREQUECY - MHZ Fig. 17 Bsebnd Spectr Adicent Chnnel interference Fro TL-2 nto TL-2(L6) Pge 23

24 SECTO : 35 n : 3 v ~ 25 A? 2 15 LO 1 n 5 Y > E -5 -lo BASEBAD FREQUECY - MHZ Fig. 18 Bsebnd Spectr Adicent Chnnel nterference Fro T-1 nto TL-2(L6) Pge 24

25 \ 1SS 1, SECTO * 6 g : ~ 45 L E / g 35 : 3 E 25 ; ; 2 : 15 TL-2(L61 _ TL-2 (121 1 TL-2 (TV) BASEBAO FREQEcY - MHZ 5 6 Fig. 19 Bsebnd Spectr-Adicent Chnnel nterference Fro TL-2 nto TL-2( 12)

26 SECTO s 7 65 v. ẉ /1 -+=A+H n 35 3 n 25 2 / / T 1(12) KEY s / T-1(18) _ T-l (leoo*l _ T-1(24) _ 1 T- (TV) _ E 5 o BASEBAD FREQUECY - MHZ Fig. 2-Bsebnd Spectr Adicent Chnnel nterference Fro T-1 nto TL-2( 12). Pge 26

27 1SS 1, SECTO v 6 g 55 n TL-2(L6) TL-2 (12) TL-2 (TV) A / 1 5 o BASEBAD FREOUECY - MHZ Fig. 21 Bsebnd Spectr Adicent Chnnel nterference Fro TL-2 nto T-1(12)

28 SECTO v o 1 cc L 1- Z? : < BASEBAO FREQUECY - MHZ Fig. 22 Bsebnd Spectr Adicent Chnnel nterference Fro T-1 nto T-1 (12) Pge 28

29 . \ 1SS 1, SECTO : R ; 3 25 : 2 ; ! BASEBAO FREQUECY - MHZ Fig. 23-Bsebnd Spectr Adicent Chnnel nterference Fro 11-2 into T-1(18) Pge 29

30 SECTO L 1- Z ~ 1 < BASEBAD FREQUECY - MHZ Fig. 2&Bsebnd Spectr Adicent Chnnel nterference Fro T-1 nto T-1 (18) Pge 3

31 .- > 1SS 1, SECTO c-l o L + n BASEBAO FREQUECY - MHZ Fig. ;S-Bsebnd Spectr Adicent Chnnel nterference Fro TL-2 nto T-1 ( 18 ) Pge 31

32 SECTO v 55 n 1 5 E 45 LL U LO 3 : A, 1X BASEBAD FREQUECY - MHZ Fig. 26-Bsebnd Spectr Adicent Chnnel nterference Fro T-1 nto T-1 (18 ) Pge 32 i

33 1SS 1, SECTO es 75 E 7 : 65, n ; 6 v ~ 55 h. : : 4 ~ 35 Y = 3 flf/ XY 25 TL-2 (12) _ BASEBAD FR&UECY - MHZ Fig. 27 Bsebnd Spectr Adicent Chnnel nterference Fro 11-2 nto T-1 (24)

34 ; SECTO Afl < n : { & 2 T-1 (18) _ 15 T-1 (18)t)_ T-1 (24) 1 T-1 (TV) ~ BASEBAO FREQUECY - MHZ Fig. 28 Bsebnd Spectr Adicent Chnnel nterference Fro T-1 nto T-1 (24) Pge Pges