BSTJ 50: 3. March 1971: Channel Spacing and Necessary Bandwidth in FDM-FM Systems. (Lundquist, Leif)

4.7 MB·English

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Channel Spacing and Necessary
Bandwidth in FDM-FM Systeme

Ry LEIP LINDQUIST
‘Memento Sptmbe 3 80)

We ezomine th eft of hay vt fering om adjacent sharmet
Inteferenon ste on ice the ese Jor Aeent ease of fering and
risus rains of Bini The wt are opaed t fapizat
lors aod av empl fornia eat anna spacing ating ond
Caine ane erence tes. We eames ootng
the opacity f Sypicel rata chanel

[Necioeary Bun oe Hewes ty the ternational Teeraman-
hicaiane Thon 2." bandit sufieest to ensure se transis
Hon of incormatin the rts cz with Lae ent pina fe che
fystam crapinged 22! Rago eka) geegumente ase el a

Sevessery basen is a woe ie suthoriaed «Isa ab leset qual
Tithe neeseary banewidss, Kf te wate tw cacti atk Wes
firher bud pully ge ard che ep are smelly nat eliwee 2
Grerlay Poe neuiy igre thin ie seviehtorwa’ avd agvisaer may
So aeiga shannsls: Venatici an ABT igaeat egal ine. om
fared within pus Frome

Th FAL syecenm buwravr te rast is not a9 lace, A WL signal
tinortivlly hue indice boast sas easing wil eae ee
ign Cn holler hand ting £3 FM sigcle next co ene oe
Tiles Foeqieey hash al ot hana sing Raewn we eanse ata
“The piven) sty o ealealating che vomceary: bane for
signals fs so vse Car's rll whieh aaten thal

=e n
S70 imams avermerremreroa, sot, MANUS 1872

Bi i the nesessary bandwidth,
Jrbsthe tap wnallating frsucy sd
Jpn the pee Fequeny devin

‘This hae Deon a very good measure to uc for necesnry benvith und
change sesigumesta, Ae the radio apeeimoa gus more aml mere ean
tsted, howave, sore of ie linizatons are beriasing te ehow uo, One
iifewty ie thst i een nob relate the necasary harewicth to che
fystem performance, Dbvious'y ae the paeeband i more and more
Testrita station will nerve, xl Ui ol welled By the val
Tevtieting the Baundiidth aeons Usb chuaele ray Be pl eae
together ott epscing rhonid be a fubalien of persaiaible rival
Intesieesee, whi is ot 2eected sito,

Hare me analyre this problin for PDMI-FW eystema, nding the
faterteonee eta ution of che apceing ap baaeand frequexey,
Zoe iregueey doviabum, ard RE telestiviy, ‘Te wade intertranee
fginse bene inching quite, we uo were ere! oer by A. Ani and
MM. Liou erlang baadlinting to distortion? They heve given an
mpiniral Joe tor secesasry handel: wich we ose ‘0 haosing
‘las hed

‘We i fie inverfernes by xumerina) eoaveltion of TOP specs,
fac Toce at she oe of llring smo vonelsle Taal “ham bos &
cheorcreel and prustiesl pins of view. the teri Fke che most
‘mnportan itr, We therfore conecasrate an the eflece of the receiver
$Eer. Ceing the Saua-Livs inion, ww compre wi iter aa
vides end dt avount clined iterereaee mice se 9 fon
ff laeding "The end rome ar erpssiea Zorn. for ezine] eben

In ahis paper wr tlle ant many <fenen: gulag raion
(S/3), and to Jowen the rosfusion Teas mersise them nekt ume,
‘Thnre exe twa scares uti, ialepesten’ of ean other: (2) Auser
distortion, Hero eal! hunvniting nose, which xe zee W hen
taccng «bout « $)N ue to baninstings aze) (8) adweunt ease
terrence ite. There it ceo a bascband sunulto-nterference
fate rolnted to an RP cattiertointsforenee avo. We hue (hl ik
{Hil be clear from the contest nish tao me ae talking chou,

‘Recent Af nd Ton aeives at the following empvical frmule
relating bandiinitng shwrtioy bn smn saviation a Eien hand wide

nexnisoneme[ SJ}: ome [B] a
vss tnvtaNEE Rus sa

whine

By isthe ter bondi

S.#8) inthe B/W in the top bacehard channel dus to beating,

ji in che top batsband fequensy, acd
{ithe ete deviation.

The signal wes areumed to be 2 precmpbasized bendimised euueres
sigue], aud the Auer were anmed to be aqzare Hite witb covert
delag. fp oan tye ieepito on che twoneary bandwith ct em
PDM-PM sina’ boonies eyinioe G2] reaten performance to Aer
aide a ignotivn of “asin whive ie caaelly al "azcessare
antics” i arto

‘aw sppiealeystam a reasons S/N ask le 70 R. Ta wractice,
howaves, fae bandicth of the filter kas to be “anor, 1 i difeat
te achieve a rellcheteved dey shanauteede over tie whule te
band ina praotieal itn. Therver, sande eacrespoadine bo DD
AP is man lite, Born tape Tae ee AMIR ae the neieo
fs a9 UD sronser bouse Ue delay canna! be equalised ell enangh
‘Rnmnaatoa of peeen: peal flrs chav ths ip lm reconable
smumprion. Ae the mata of tae ar. changes. syn Vw yw
"levease the teaser bandh to Laat eorreaponding fo 70 4B.

Tasesing 99 eB into tae forma fer By bel

By = BI), — & Cy

‘We ssl fia he base base saterecenee from naar easel
fe a faaecion of aging Tove nN eseave tat “he to eaanne's
fre identioa ead Tene sth bal vited ganic igaalaexmalatine
Truftckeanel tlker Toy wl “hat the chases ace faz ero
that ake Sestarder cider da mot wrlap. Te worst interference
sll he in the tap velse channel we rer! In corto the slgzal-
Tien ference vat in abet ohasne! dae fo too ad)aeene cheaele,
ranean sath sige

uy aula have shown 42° folowing forouln for Ube bese
hue doe aa avallinoe"sing ea

8 = 0 + 800 rc
where

Wi) = Bsn at — 6
we voaban, #VANESUREEMSTOAL FOMESAL, MARCAE ETL

an

Ee the I wae eatin
Fel,

ui te diem fsqueney Tes earn,

aud, are thu plioes due tu elution of tke wanted sad wa
‘wanted signals raportivey, and

<¢ Hea minder ange uiferely disnuted rom 040 2

of ye ct an ytd Hg,

Aquetisn (5) b xe sppoeximetion for null of te cute gear
txpressice derived by ¥-K, Probic sil LT, Enlee'@ and sre mot
{ndepealent but eve unocrrlatd beonnve the peated value of exp (a!
is equal to 0, Purthornare Ue lime aveege nf exp (ut) ale O er

a 0. he iqaoritertnce tn ma ha Fone hy Bing
Ue eato of the events of dy al
and are apeuived tae Tnkegeels of peramchesizod aussi
varinles. "They ve enied speoine aul The sane mesma
Aviat, The apetouns nie
sane PER,
®, lawohore ©

the baseband fequenes,
4. is tho top baeebaad trenumnry,
1 the Berson bared frequency,
Pre (isthe precraphuss fuaetien, snd
"i tho rine frequeney devition,

AF there's sw RE Bherng the spectrom of y, Spm Ms fo
actly by computing the specimen of x err of per 8472 plese
modulates by fy dol. Thi ia similar cp Jodie dhe RE pecteuca
ff ono ehnal, gy end ote ential gvuasaus aud gan tuo
{gioscicn with ties rhe ower In the stm sbecteal shape. The spet-
Th fe eh = tt be rarer a ates 9” FOneeruive
onli aed fe ea

eae 7
the spectum of ¢ ia!

alte)

wot Rania + Es suresa] 9
‘When RE stern i pple, vo lange gasssinn another tbe
Ihave to be used (udu Sy. The oat eeemnom way isto runvulve the
HE spectra? ‘Tbe origial RT petra cam be tour using equation
(8) snostituting vy fos 8. 'Me RP selectivity fe thea apoio to Ue te
‘omtiea poeta, Thae ltrs may be brvulva; leansmitier ltrs in
th cine ands resizer iter in the wasted chaarel. Finay the
filtered eoeetss re convolved co get the pele af

"Thief the appreveh Laken this papas, We found she RF setre
hy ang equation 18) aisige the Peck Fourier Traratorm algrian in
pvfornving the conveluijns: The epestr wer ileal iy sure or
EX with che vce RW levadwlh eaosen to eos specified areount
fF henclimitin nolo, Bysntiow (2) var used to detewine Lie nove
Sey inmtwith ene te ltrs wee asstmet to buve inte Iss ot
Tide ita hendidch, Se tte FIC ova with samples of spacey he
feqaze flare renin’ che seples outside the pashene, ‘The inl
orvolution was pero nomeric ly on the aetmaing Samples we
fer the interferer ine fs te tom abuse, wrt sho signal semple at
Thal trequerey ss exided y the interfesener us yet the azealee
interfere rai.

We uo 4 samples nthe astound ord 15 teens nthe series jn
fenvation (8). All eels Rere normalized tw je an we found che
Sivualetosiserteeato cali > “inetion 9: ebonbel soneing forests
(and for savinvsmnstnt ¢2bsatansng ier 0] Yaeiops combi
iene of Stes, ffs nas asvmnes to be DL lil is 8 Teesonab ep
wrosimatier oft wlipen Ine “ee preezphiia Was that reous-
nese fy fe CCT

beh

o

a Ree
We Pave anipszad intenforenee nue fm hve adjacat chur,
fam rach sie of the wanted haariel sanction of eons
‘ecatign, and bending senior, We ete aur eases of
share! elactivity’ ne ters Ircweniier ters only, reeicer "te

fini, ane both trsmstiter va yoriver Ther Alle weelte are aot

invade Lala apes Ooraaee a ey Tage amount aE ce ee gen
fated, We will sow sess of thr spins. resale ars epply the
esl a type) tadia clay systems
‘Tie eampuier oranse were written to compote the top chine
interference acee ua Zution 0! inereasiny evannel apacing ane for
varios w/fy ann (S/N) due to bendlimiting, The progr are spevil
Yoreione of general programm shih computes the KE gpeetza of two
EDM-EM systems, npplise Ploring, perforea the canvolstion, and
slits tho epecton. Wo the Trequeaey ifn "Pie yi che completo
bbuscband inorconee spoatun, and, to eave computer tino, the =
finns wore crane! tn monte only top banal aoe,

Tae output of the peugene was the sign toda ratio
the top ‘nseband fregusney due 70 terrence “rom be aujecaut
‘xoncls nsmalied to an RP veo of €-aB, Figure 1 shows tis for
the rane ho Lanett A analy of curves, each Zar diferent
aff ie shown, For eae oeae of filtering and 9 eyed! wnaunt ot
‘aol irgdstoehinn ela onevas hav been ganazacee, Fron: te
curves ether ainven aPowing Ihe channel anecing ae fanaian of evi
‘tion er count bagchard sgasi-to-intentenenoe 2p eam be g6n-
ewe and Pig. 2 shoe the fos tee eae at no Btesing

a The Bet of Pre
‘The maxims amount of urine possible s wbea both trans
‘nd reteive flere aze wted abd this aaturay will genszate telnet

i: ES

Mig 1-Signa-e-Noie aio a «faci of ecu! ancl, No Stn
ghetol atthe ly kb

ig, 2-Cownnct Spring we «fin of dviton No hors

snout af iterorenes, Wea ho shannel sparing oxeeds cho fey
Tomes these wil he xo iutesfem ao noige because tl» beer
fll si ronuve The tae of te san soeetrm an Uv reser
filles the set

"hen ony canst ili en ised share i) Inno nterforece
swan the ebenoel spaving twos Lap iter buriaicl ps the top
Paatbane froqscucr, Fo love eae oyaving there ti. he beat
proses fling lachasc

"The reesives Ele wil nave nny ofthe adie haul suegy
sl in pantivilar the eater, For lew-index system, ie nae. por
lurk pat af fae convolu-ov i Hiv Teatiag af one entrier sth she
silebnl ofthe ote. 2 Lae ural! rive ie nemaved, the iter

Terexee power wil le iced hy o fclac of 2. For higa-inuas yen,
{Er atunlun is more remplieatel trea Cr sidemnde ear quite
far ue Iie cari fceueney ex! Uwe sa"er el a very anal
‘Figure 8 dows the chan) -oaring ae & Luxetion of chitin foe
the conn of ao Eleeg, truce” Bae only rover fillers only
sin] ol rants nid, nevivs iene. Tay Bere are cum sult
thet Oe S/N sve "0 bending e 70 <B. ‘The #gualtucin ef ronee
retige ne tl ave AA wie sila un RR tein of ~a0 db eucrepeorle

tr haeei sganite-inbe ence retin of 70 uo 80 <P,
Arne ean ott ther Is com etfcet of bu iting, The trailor
‘ey ele ge the had Pant and the eeeiver Jn aes es of he
rec mouusvnny cacao souatta Sant Loh

ig. Feet Whig. — plc, — uma sony =
retail hry, and i gol’ Ga or ofa Fe

inte-lreven ovjntion and the comchination of both of couen pru-
vider she bet protection

‘Tn tara of ebannal spising oF increased expt the eft of Mere
{8 cnly reodorate, Un le LR eure at o/f, Ou hy relative change
of aff 60/5 ~ 7 wer, The cures aro wameriint deoeplive how
fer beat i ye look at Fig 2, om inerone nf 0.2 f, 1B af wichoxt
‘ging fs nsw suletentiek reduction woe, even HT 6 ignore
‘tho eo! vesinivy i Sh anrvee acd amare tht hy ere evenly spaced,

30 Raining Ditton Versus Adjacent Chonoed Piderference

Tr ont radio relay nystnca the lull 0 she Altering is ut the
eveivar and ve shell tntefoce eonoentvate om hie cage, Figures 4 7
thaw te lneebane #gialtorncerferanee neo fo agaal-te-aoiso ch
to hanalisiting eqal to 79,80, 0, nue 100 €B veapeotively. We eo
that ging from 10 aD to 109 dB de wot change the euzwos by very
rrnch. J a praehoa, sytem: the TU dls curve (Fig, might be of
fveatetintarert beeacoe thi ie aenaunlic limit oF se Deo
hates, ae we mimfioned in Seetion IL, Glters eennut be designed
“which we te Landi: comesponding to 70 gl without goreuting
IMldbiona) noise one t0 delay detorin, Lorna oxe tne “0 go to
aml varespovaing eT. To leignizg 8 aptem,thecefore,
‘the curves in Pig 8 orl bo 0 pen ieee! Tie ine Aa Ue
co

Fig, Resoe ler only Siennsise fm Banding = 0

ste of the <r: changes, Horever, we might approneh the eurves
Bes

144 Channel Spacing Korma
rom the ourvoa of Fi. 6, have davived he folowing empties!

‘emia

Vig | scvr Bir ely, anomie tn ending = 9 AB
S78 tauaeas siernacwonnteat rommest, Manco

obit nied

ig. @-Remive Slee

Signal nae Dati ~ 99 JB.

a= a4(s 4 00a (PS) + Lhe hon (SE a

19)

‘This formu uot well God ty che eurvs jn nll he dotailybersoe

the curves aro aotwell babovod, Yor the purposs of davign howovar
Deliavo tht the foraul i adequate. Yor very Uetuiod soudy, the b

Fig T_Ressser filer uly. Sigulc-sie fom bending = 10

et