Sherwood MICRO/CPU 100 User manual

Ðeârtr fomêr:
Yaar,She"lyL'CIc<l llílcR}/cPu t?a Tuner.reþrësents a stftte."al,úe4rt leteî ìn compt*èr lerknolaEy'
apptied lar the fírst time to a hìgh-fidelity r:omp<tnent, The contl¡inutiott af features and perfrsrmuice
rhis tuner pravides vvailt! be impaxíble to abtoin using conwntìonul technaloay, ond we at Sherwood
a¡e confident thdt these unparoltelerl technolagÍml otíwnces will pr<tvide yàu with tîr¿ny .¡ears ûf
penonal plausure and enjoyment,
Thank ynu for choasfng therwoad!
Sin¡:erely.
Shrluw<xtã I'i lectr/J ¡tics I"abüatttries, l¡tc,
Contents
Frnnt Panel Feaülres,
lnstallation .
Tunar tonrTectíon
Tuner Rrcepticrr .
Trrner Operation ,
Additisnal Feâtur,us .
Block Diogram
Specifications
TyBical Perfarmance Curves .
Cornmon I rrstal lation Problums
Notes
l,Vårrünlv I nf ormatíon
Station Log
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22
wARhl*Nc: rO PRËVËNT f tñE OR SHOGK HA?ARA, DO NOT gXpOSE
TT{IS TUFJER TO RAII\I OR MOI$TUNE
-2-

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ffts ens}pred:stsr,r.qnty'.sald m¡pt he :.fil]ñd is$t.:ralTd; r#t$raêd iu Strsr¿Íüsd;withîfi. ,I.ü.:dayçsfær
,rççfrfjrt 9f vg¡;riltu¡gr ro tu-ÍfrJf.l*areantf r,çqglr,emçpts, lhç cnr¡acr nrsdpt:sÍ{d:$rial Fqmber.øn
;h rç,.Þ{rçd :fru¡l:'tfp hqclc i{âhÊt::ol :W$i. t¡t¡¡t
üAv€ -T'gfJ'$ S¡4,!;R$i'ff ES8IFI*FROSF
ñ€sÚ" ffiIN6 lÄfAH,frAf{TY $€Baú'tcË.
:ts$ìr¡!Êd trÉJ:rrid,Ê ¡íffrmätürn
;DËFbflrrfê{ü.. :FI(âTA ùp'êcfftt
,ûg"fr:çSFondßncs.
#F,ÞArE oË F¡¡Fêt{d#E:. L$i Rtü$ I RGg .tïÉlFN
i* availabln rilni rçgt¡çr-t fiom $hçfrimod'r TerçÌffifsal
thb ;êXstt: llrÞ$ç,1ì fid ,Êår.idl rrrfirrþcr qf' .fgüf tu¡lef :in
IL- -fl;

Frsnt Panel Feafirres
F igure I
-.4-

1. pfigGRAM svlllTCHÊSt permit programrning into memory ûl up to 4s sets of statiçn identification uharacters
for reado$t on the Alpha Numeric LEF Display' {Page 8'}
n" SIGÍìIÅL STRET\IûTH M€TEfi: lndicares th* relativä signal strqnglh of the selected FM ltation. tPage 7.1
3. MULTIfATH MGTEF: lndinater ths âmount sf srrdesirable, reflected signal being received älong $J¡th the main
trånsmitter $ignnl fcr best antenna orientatlon' (Page ?")
4. MEMOñy ûl{llTCHEsl 4 touch s\rilch conrrok rhat ofter con$ßnient stûrage of 4 f¡vorite ttðt¡onå fqr instant
tuning" {Page 9.}
5. ILLUMIilATËÛ TUNING STÅLË.
û, ANALOÍ¡ nlAL Fü¡NTEÊ: Miniature LEt* arranged in a lirre below the tuning scãle to indicate the movemeÌìl
of a conventional di¡l Fointer. (Page 8'I
7. ALPHA l\tUMEElc tllspt-Ay: 4.character LEÞ readuut used with the Prngram switches {or up to 48 sets of
user-programmable letlerlnumbsr conblnations' (Fage 8')
t. DlGlîAL TREOUENCY DlsptAy: Large LES di:play that indicates the exûcÎ frequency of the ståtion
selecTed. (Page B.!
s. Auîû.ÎcAl¡ swlTcHESl nighl {and Le{t} rouch switches thät scån up {a¡r¡d clownl the FM band to the next
lrrcadcasting $tat¡on or $1ërço broadcasting station' (Page 9']
10. ûOCIR Pl\NEL: For convenient acce$s 1o variour contrtl functiqns.
11. OUTFUT LËvËL coNTHOL: Volume control for matchÎng the tuner output level to thãr tf other ¡ignal
çrurce$ in your tystem. (Page 6-l
12. ruuïlftû LEVEL CCNTBOL: Adjusts the thrsshold åt which intefstatìon noise and very weak 5tôt¡ons âre
mu'ted when tuñing belween desired sTãtions, tPaqe 1Û')
13. MUTING $wlTcli: Defeats the mfi¡ng of very weak stationr {ancl interstation noise} permitling fecept¡on st
any signal ,strong enough to be detectd by thn 11169¡' (page 10')
14. SELËcrlvlTy $wlrsH; 2 seÊarate lF systems províde both a "Normâl" bandwidth for superb selectivitY and a
"Wirie" bandwidlh for exceptionãl stereo fideliry^ {Fage 1CI-}
15.AuTt $TEÊ80 FILTER $UllTCH: 0ffers maximum noise reducti¡:¡rr on noisy stereö bfÕãdcarts with a
rninirnum of lost of high frequencY re$fionie. {Page l0'}
16- IVIOOE $l,lJlTCH: Provides for rhe selection o{ either Stereo or Mono modn of opÊråt¡Ön'
1?. OEEMpHllsl$ stlrtTcHl $elects proper deemphasis {equalization} {or either normal FM transmi$ion or t5¡rsec
specially encoded broadcasts. (Page 10.)
1g" îuNlfic CÕNTñOL: tqerates an electronic deteclion r¡rcuit that provides smoath acro¡s-the'dial tuning
w¡thóut the error and mechanical limitations associated with conventional tlywheel tystems. tFage 8,)
19, MAIN POWER $T¡¡ITÛH.
*5-

lVlren installing the M|{IRûICPU tuncr,llte fcllowirrg
sjtuati¡:rns rhCIr¡ld b¿ avt¡ided that could possibly
damagr: ttle tuner:
r Stacking cornpünents which limits venlílation:
. Plaees with pt:or ve ntihtiun;
r Places expnsed, fi: direct tunliglrt, cluse {o lteatirtg
unitc or ¡lher sar¡rcer of heat;
r Exces$ivel-v huruid or dusty luualions;
r Sloping locali<xs cr t[r sc subject tc¡ r'ibration.
IMPüR1'ÂNT: Á,llow a( leâst Lwu inches of space
behind your tunùr for adequate ventil¿lion as wcll as
catrlíng c<]nvenience. ì\cvcr plac* the utì¡t netr
lnstallatíon
Tuner Çsnnecfton
rodiators or in front cf hcaling vents. Ëxcessivs helt
tcnds tc¡ shorlen the life a[ Úte intçilìal r:ompunents.
(Thi¡ ia aR inrportanl facl to rcmeinlrc¡ irt c*ring f'rrr
cll the clümeilts of yr¡ur ltigh-fìdclity õysleln,
includirrg ¡ecurd¡r and tapcs.)
VERTICAL MûIINTINû: ,{lthough ycur Sherwoad
MICRCIiCPU loû is derigned lo be placed in a
horiz¡nt¿l posilio¡1, it .may lie nlounled vertically
(wiilr fh* face plate up). ln this Ìypc of ir¡slallation,
úo not u$€ thc encloeure. Thc tunel may be
suppcrted complctely by jt¡ cscutchccl:t itt ¿l {:u$l*m
irrstaltatÌon; howcv$r" this type of *tçport is not
adeqtrale tu wi(hstand thippin$
The MICR0/CPU tuner $f:fers fwô ltlâilì auditt
qrutputs: F¡XUD and VARIABLË. The fixed ouTput
ol'fers a ncminal ùutput level that is governrd by tlte
tuner and nevet varies, Fur tnpe recording directly
from the tuner r.rr feeding Ít 3tcrßo sy$tËtn that
requires a nonvlrying signal *tlurce, this pair of
ùulputs would be selectcd" The Varilble (tutput isi
adjustulrtc with â front panel volume ootrtrol lrrcated
behind the d<lor psflel, and ir usually the chüice I'ctr
rnost ster€ü uyutem* si¡tcc it p*rmits adiusling thr:
tr¡nsÍ Ëütput to match that üf nthcr srrurce.s (tape,
phono, ütc.). "llhis will rlso aid taping, exlernal
pracessing or nfhst cüffpenents in yrrur aystcrn ilrat
måy require aúju*tment if a sigrr*l level r¡nries
bctwe€n sÐufce$.
lJsing the ¡ruir l:f'cttblcs pru:i'ided, connctt lhe tulrer
ùr¡tput Ûf yout choice 1o fltc tune¡ {crr aux'J inpnts Ûn
yonr uorttrol amplifier.
CÛMFO,$ITE ÛUTPUT: This jack is providcd cn lhe
back psnel fur usE i¡t conjunction with ilI¡:ådi-lptÈr
{when approvetl by thc UCC} tó praducc 4 discreet
channels lrom an FIü sc¡urçe, In the sven{ that tltü
Fcderal Cammuni¡:atiorts Cori!¡il¡si$n aPFrove$ å
standard mgthsd crf 4+harurel translnissiono $ller-
woorl will then nffet an FM 4{l*rxtcl adapter l'or uss
with this jack.
-s-

FM ANTE¡ìIÎI{A: The'dipole' ânt€nna provided with
your tufiÈr should be adequate for local FM
feceptio¡r. Cornect this anlenn¿ to thç t\ryo terrnjnalr
marked '3û01;'on the back of llre tuncr per Figure 2.
Attrc.l the antçnu¿'s 'ârms' horieoltalìy tú ír
nnn-ffetallic surf¿c* such as a window, ¡ wall, or the
re¡rr surfâce *f a cabinet nr shelf-ïvhichever pusitir:n
¡endsrs lhs best ovsrall r{ception, In generaf, the
illtën:lâ ìs bcst posilionetl when it is as high as
possible aborc lloor level and its itxns årc
peryendicr"rlar to the source ¡lf trangmisícn. l.[Çr.vever,
in some strong signal ltcalitics, plâeem*nf under a rug
0r mrpet msy provc âcccptâble.
lf you are louated a $ol*ideri¡ble ¡listancc lrom the
FM t¡r¡nsn¡itl.er$, Ân oul.d<rnr þM antenna {availabìe
lrtrnr your Sherç'aad Dr:aler or TV parts dìstributur)
mny be rer¡rrirecl ta rcdr¡cc i:a*kground rroisc. ûrding,
<lr inte rferencc. Thc followirrg nutes slrould be helpfirl
frrr rny antÈrìna i¡lstallafiun:
l. lt i* alway's advisåble tÕ kcep the ¿r¡tenna
cahle as shorÌ as pcrrsiLile.
2. Try and keep tlrs anlð¡tra a:; far away as
prârticül fiorn the ftreËt fo avoid igni tiern
noise from iu¡tûmobiler and ¡Íher vchicles-
3. Sincc antcnnns sre directionll, its heighl and
dircction should be adjusted while actuatly
receiving a làvornbl¿ Flvl station.
Tuner ñeceptisn
t'ttoon DtFoLt Foñ
LOCrt iÊc€¡tlor
4. Avoid placing the antenna lcad.in c¿ble nesr
the electrical power lìne that eÍters your
lrome .
lfhen using a 75 ohm antenná sysrem, itr enaxial
cable shr:uld be connected as flollows: The *uter hraid
shicld (ground] should b* held in place wirh Íhe mptal
br¿cket per Figrrre 2 (which xko estatlishes a grr"runrJ
c(lrìfler:l.ìön lor the shicldi and lhe lnner conductor
rvirc shoulcl be c¡¡nnected rn the lenr¡i¡¡al marked
*75r}.',
SIGNAL gTR[-.N{;TH snd MULlìl}'.4Tll MËT.FIRS: A
ilûst ¡mf:ottrût l-åútor af}:cting FM signal qualit-y is
multipath rccepìion. This is ca*sed by rignal
refleçrions from hr¡ildings, hillr. et{.}., ilul rcactr the
tune t's âtìtsnn¡r lafr:r ir¡ tinrç than the ndginal signal.
Parficularly with lîItl stereo, multipath ç{n caïse
sever* disf¡:rlirrn a¡rtl lrrss (}t channel separation- TÛ
help combaf ttre eflecr¡ of' rnultiparh. the MICRü/
CPIJ 100 ernplnys a Multipath metër*it visuat readrlut
of thË sf rcrrgth uf unwanletl, r*flc*rsd signals-
Bocause antenna orientation is a big taclr:r in
minimizing mrlt¡p¿th receptiûn. a dircctiunal ãntê:trlâ
equipped wi¡h a rûtor to "'¿i¡fr" tl¡e ûntðnûå lor
miuinrlrrn mullipal,h warrld be desirable. Since lhe
Sigtal litr*ngth mc{cr irnlicstes the relative strenglh
of the incomilrg signal in its entirery. tiy chucking fhe
twü mëlÈrs t"or both minimum multipath and e:rough
Fþure 3
*]-
tc ttlrFtct

signal $trèngth for noise-free stôrso, you hav¿
n$limizÊd rÈccption for any sel*cted statiofl. lf Ìhe
tlipole suppli*d or a directional äñfenlìÍl tl"irhout å
rotor is adequate., vary tlr* âflÌcnnâ direc:lion until the
tiest c¡verall avs¡age nl' signirl strength and low
rnultipath lor fnrrorite itlâtions it obtained.
The htlCRO/CFU l0û'l computcr lms s ttiiling
åçcurâcy uf great^er than .0Û24flat thcrefcrrx, tlrc tuner
har no need f'nr ¿ conventicnal "center-tunê" fiìetcÍ
or an oscillosrope 1t indic*te ¡rccurûte trrning. Ás
ncnlioncd, lhc fu¡o mctcrs are provided to aid i¡l
flroper üntqnnä crirntation, and should nat be trcâÎcd
írs "motiimum deflecdon" or'ocenter-luning'''
indicator¡.
Tuner tperation
Once {he cüllnecti$ns oullinrcl in the previous
recfiuns have bec¡l llrade, your MICRü/CPIJ t0û
lun€r is cnmpletely opemtiunal. Althorrgh thc
MíCRO/CFU 100 is nût dilfìcull ({} (}pûrâtð, careful
study of this section al' the opcraf or'$ ma*ual will
allow you 1o l"ully enjoy its many ver:latìk tþaturcs.
M.AHUÅL TUNIN{i; Your MtCRO1ilFU lt}t lurter
rn*y be rtlårìuálly lunccl hy turniúg thr 'furlirrg
(irntrol tr'¡ th* desired station. 1'hc l)þitat Freqrrency
Di:play give* the sxa¡rl. firquency in nregrhertz
(LlHz). The Ånalog llial Pointer ìndicstcs rel¡tivc
pnsitiun on ü convåntional FM rlial scnle, when
atlemptirrg to bcate a particular stâtion, Õrrcr: yorr
have tuned Lo tlre desired sl¿tiou, thç¡e is no nced fo
'firrc tunc' :¡s thc MtCR{)/ç"It l0ü's compr¡t*r will
'lr¡ck in'nn the tlesirett s{ation.
STATII'N CÂ.LL I-ETTER PT(0üR.ÀtitMfN*: To
progrä¡It the e¿ll l*tlsr* ln¡ a parlicular $tilti(r$,
*trrtutlly lunô trl thilt sl.al"iou. T* i:ritiate tl¡c
progrâ¡¡tÌfli¡rg ${t{{.encè! lrtuch the,{tplia rwitch
I$sated ón lhr front p",rnel" tly turning the "l"unirrg
Cuntrol slightiy. tfic lettcr "¿1," rvill âppeñr in the first
ptsilion nf the Alpha Numeric tlirplay, Rctate the
'l'uning C¡r¡rtrol until the desired û.häracter tppenrr in
lhe Alpha Nunreri: llis¡rla¡r. Tor¡ch the $tr:rc switsh
f.o re l¿jn lhe rdrarac{¡r. 'l'he letter "4" wili uppear in
each silçcessivq pç$iri*n t¡f' thê .Àlph* Irluru*ric
llispluy, whcn thc prcvious charfictðr iç ¡torcrl. Ror¡te
the îuning Cnnirol ¿s de**ribed above I'or sach
posilion $f the Alphâ Nr.¡¡¡rcric fli*plry. .4,1't*r str:ring
rhe fnrrrll¡ chôrauler, Lhs r:*nrputer aulomatically
switches your MICnOICPti 100 to its n*rnral
operating mr:de.
HûTI: Whcn first aperrting yt¡ur MIfRO/CPU
lilll, nrakc sure lhilt all thc flip srvitches lre in the
'up' (normal) pr:sition. Thcsc switcheri ¿rc Lrcaled
behind the door on ,ttle f'rnnt pancl, ftr open lhe
duor. press inrva¡ql al ilre bçtturn edge . The ldddon
l¿tch uill relc¿*c ar¡d the daor rvill np*rl. To
engäge the l¿tch" sinrply closc rhe dc¡or.
Also" û¡âkc sLlre f hat The Fre<¡uclruy switch,
Itcared o$ ths back panel. ir in th* correst
p(¡sil¡ùn. For use hr lhe tJ.$i., the *witch m¡rs[ be
in the tjdd pr:rit.ion rincc ull U.S. fM stari¡:nÍ ars
asrigned odd numbered liequencies by thc Federal
Ccrnrnüniùatio ns C ummissinn- ln o f her r:ouu lries,
chcck with your lcrcal bro¿clcr¡sl^ers ro derernline if
they are bro*dcasting trn tdd clr evrn numhe red
frequcncies.
-8-

Oncê the $a¡l lelters åre progrÍlmmrd to a parricular
frequency" whsnever you tune ta th¡t frequency, lhe
asso*iated catl letters will äppear in the ÅJpha
Numcris lli*play- lf yr:u rryish to chatge the call
letters, use the previously outlined prccerlure.
If the Alpha switch iu ünintentionally louched
fin:tia!irtg the pragranrrning sequence), the pro-
gramming sequenct may be ca¡.¡celled by touchirrg the
Alplra switch again-
NOTE: The Alpha Ntrmeric Display uf your
MICROICPU lü0 can be programrned rvilh any
four charactêr co:¡rbìnrtion öf letters, numbers,
and purctuatian f'ound on a stantlard typewriier
keyboard, Iiince ,s¡nre stations have less than f'uur
*all le tters, a blank, or $p:rffi, is also pruvided. Dcr
nol progran dl positiorrs af the Àlplra Nurneric
Ði*play rvith blanlcs. Doíng sr: will tessen the
¡lurnbcr of üell letters sêts thst çâ¡r be
programmed into the conìpnter',s nrç¡ntry.
A *r¿xi¡nr¡m of 48 sets r¡f call l*tter* c¿n be
programmed inlo the r;ofnputer's merntrlr, [f you
åttempt to progrem in rncre than 4tl sets. thû word
*FULL"' will appear in the Alpha Nume¡ic Display
far app¡oxinrately two s€cÕnds. Addition*l rels ff¿y
bt programmerl in, i.f unwanted sets arc first rle letrd.
Call lettcr scts måy be dclcted by tuning to flre
starit¡n whose call letters yru wish to delete, touching
the Alpha switeh, and then tuuching the Merrurry
'?" switclï,
MEMOR.Y SWITCII PRüüRÀMMING: Four cf your
fsyorite stations n¿y be instantly tuned by tcuching
the f¡ont panel Memr:ry switches" To store s siatiûn
location in a plrticular Memory, tune to the desired
station, touch the Store switcll, arrd then tüuch the
desired Memory rwitch ("4," "8," "C," or "¡)'?¡.
The *tation cân nÐlv be ilstantly tuned by totclring
the associated ltfernor'y switch. The unique Mernory
þlatch feature nf your MTCRO/CFLI I Cl0 wíll light the
associated Menrory switch ench tirne rlþt stariôn i$
lruted. Thh alerts you tû thu fact that tlrc tunetl
stíttifin is slnred in a parficular tr'femory. Stntions in
the Memory nray be r:hnnged b¡, rrsing thc previously
mtlinsd procedtrre.
AUTÛ SCÂN: Touch switches allow you tc sr:an up
ur dnwr {to the right or to the left of) rhe errtire FM
band. lVhen activated, the coruputer prnceeds in the
direction you choose; ts thtl ne¡(t broâdcâtting
statit¡n" I{' use¿l in conjunclion with the Stereo Onl,v
switch, the computer will select only those st¿tions
broadcasting in ¡tereo. If na statiolr$ are detected,
your h{lCRCI/CPU 100 scans tl¡e entire FM band nnce
¿nd icrminates al the origind fiequency.
SHERVT'OüU
@
HF:000 Coníral Arnplifir:r
*-Õ_
MICRO/CPU l0O FM T$ner

'...-
¡ÎELECTIVITY SIVITCH: Your l\.ilCRCI/üplt t0û
rmploys trvo distjnci ll- syslcnrs. lVlren neighboLirrg
stttinnr oiì thc l'M band ínterlbre with the reccpliorr
r¡f a rtesirecl srã1i(xr. tl¡e Nnr¡a¿l lF systcm, whiuh
pnrvides stt¡retli sblsstiyify, should t¡s med, -fhe lllide
IF,systenr providcs exceplional srÊrer) sepâråti$n ând
lnw distarliorr. The TVide lF syrrre¡n shorrld bç uted
wlæncvcr ncighburing sfat¡ons dc¡ nr¡t interlcre with
lhc rereption uf the desìred llation,
The Nurmal or lVide [F systeru is sclccled by the
front panel Selectivity switch.
lvftlïlFlC: '["h* rlcctrunic nruling circuì! will renrnye
noise nr¡rmally lreard helween stâtion$ nf highly
sensitivc þ'hl turrers- The Sluring l,el'el Control slroukl
bc udjusterl t* rlre point al which lhr¡ ínte¡ffarion
noise is eliminated- tf thc Muti¡rg Level currtrol is
ad,iusted f'nr higher $gnal levsl mrting (rnore
clockwise¡, thc $:und of extremely distant. wcak
sl¿tions may alsü be atte¡ruated *long with the
inteislaliun noise, Thereforc, when rlesiring to fune in
a knorvn rueak station, adjust the cr:ntrol rnon:
cc¡u¡rÍerclockwjæ to reduoe. the signal lcvcl mu{ing
(hrcshald, or defe¡t the rnuting circuit tetåtly using
the Muting srvitch.
AUTO STT Rgû FTLTER: The Auto Stere¡¡,frilter isa
nrliss cancelling circuil thät äutomatically ¡ç¿ur*t
background noise rvÌthout affecting frcquency
rc$¡)olrsç il¡ prupnrtir:rtr to the strength sf thø
inclrning sign*I. Since the Ar¡to Stereo Filtw is
inoperatir.e whcnever a sþnal is strong enough ro be
lre¿rd in fi¡ll stcrco rvíthuui. noi¡e, Sherwtxld srrggests
that it be lcft on.
Tre Auro Stereo Filter may be delèated hy
depressing th¿ lrr:r¡lt punr:l Auto Slcrçrl Fiìter swit,ch
to thc *'OLIT" posifior:r.
IV{ODD lílVlllCll: Wheit ihe Mnde switclt iidepretsed
(o tlre Mono position, the nrultiplcx cirsuifry .is
bypassed cnd ¡¡ll bfl:sduasts will l¡e lrcard mnr*-
phuninatly.
Á,UI'OMA'IIC STËK¡:OIMON0 SIVTTCHING: The
MICR{}/üPU lOÚ incorporatçs a uniquc rroise.lhres-
l¡old:gxted autcmatic slrrreclmo¡rrr swilching circuit.
Whe¡l the Mode switch on the fronl parrel ís ret tro lhc
S¡ereo pr:sitiuü, ¿ntl th¿ FM program selected is trcíng
broadc¿st irl ntono, thls ¡utr¡matic eircuit swilches
the tuner irrto a mono m$de" Stereo trannmission í¡
indjcated by ttre F[{ Ste reo Indicatar Light k:catrd in
the tuning $cãle írreâ, ¿nd the tunçr will autonratically
switch lü sterðo or rnono depending on the signal
rtceived-
Flvf DEEh'IPHASIS: Tlre MICROICPU lû0 tuner
forcignJ.
* The word '0¡lby' ¡r ð trådÈmark
of Þolby Lábotâtoi¡€r, lnc.
*10*