 stresses which can result in slight variations in movement past the transducer. Since these variations may not be reproduced in the transcribing equipment, the result will be a pronounced difference in the frequency of the reproduced signal and this will cause undesirable variations in the quality of the audio reproduction.
The foregoing disadvantages are overcome by use of the so-called capstan drive. In this arrangement, a capstan is mounted in the recording machine immediately adjacent to the transducer, and a back up or pressure roller assembly is provided so as to press the tape into feeding relationship with the drive capstan. The pressure roller is moveably mounted so that it can be disengaged from the drive capstan when it is desired to stop the feeding of the tape. In order to prevent slack tape from building up between the drive capstan and the tape up reel in the cassette, another drive is provided for the cassette take up reel which rotates the reel at an angular velocity fast enough to wind the tape upon the reel when the reel is empty at the same linear velocity at which the tape is being fed by the drive capstan. Typically, a slip clutch is provided so that as the tape builds up on the take up reel, the reel can rotate at a gradually slower angular velocity even though the drive to the take up reel is maintained at a constant velocity. A principal advantage of the drive capstan feeding arrangement is that the recording time for a given length of tape is maximized because the tape is fed past the transducer at a constant linear velocity. Another advantage of the drive capstan arrangement is that it affords excellent control over the feeding of the tape past the transducer, particularly in that it permits the tape to be fed past the transducer at an extremely uniform linear velocity, thereby greatly reducing any tendency toward audio distortion resulting from variations in the movement of the tape past the transducer. Also, since the drive capstan is typically mounted as close as possible to the transducer, there is very little likelihood that the physical characteristics of the tape will in any way effect the uniformity of linear velocity of the tape past the transducer.
There are however certain problems which arise in connection with capstan drive tape feeding assemblies. One of these is that the capstan must be driven with an extremely uniform rate of angular velocity in order to achieve a uniform linear velocity of the tape. Since the drive capstan is typically a very small diameter element having very little mass and therefore highly subject to minute inertial changes, the drive input to the capstan must be very accurate. A second problem is that not only must the drive
stresses which can result in slight variations in campaign past the transducer. Since these variation may not be reproduced in the transcribing equipment, the result will be a marked difference in the frequency of the reproduced signal and this will cause undesirable variation in the quality of the audio reproduction. 
 The predate disadvantages are overcome by manipulation of the so - called capstan driveway. In this musical arrangement, a capstan is mounted in the recording machine immediately adjacent to the transducer, and a back up or pressure roller fabrication is provided so as to press the tape into feed relationship with the drive capstan. The pressure roller is moveably mount so that it can be disengaged from the drive capstan when it is desired to stop the feeding of the magnetic tape. In order to prevent slack tape from building up between the drive capstan and the tape up bobbin in the cassette, another drive is provided for the cassette take up reel which rotates the reel at an angular velocity fast enough to wind the tape upon the reel when the bobbin is empty at the same linear speed at which the magnetic tape is being fed by the drive capstan. Typically, a slip clutch is provide so that as the tape builds up on the take up reel, the bobbin can rotate at a gradually slower angular velocity even though the drive to the take up reel is sustain at a constant velocity. A principal advantage of the drive capstan feeding arrangement is that the recording clock time for a given length of tape is maximized because the tape is feed past the transducer at a constant linear velocity. Another advantage of the drive capstan musical arrangement is that it affords excellent control over the feeding of the tape past the transducer, peculiarly in that it permits the tape to be fed past the transducer at an extremely uniform linear speed, thereby greatly reducing any tendency toward audio distortion resulting from mutant in the movement of the magnetic tape past the transducer. Also, since the drive capstan is typically mounted as close as potential to the transducer, there is very little likelihood that the physical characteristic of the tape will in any way effect the uniformity of linear velocity of the magnetic tape past the transducer. 
 There are however certain problem which arise in connection with capstan drive tape feeding assemblies. One of these is that the capstan must be driven with an highly uniform rate of angular velocity in order to achieve a uniform linear velocity of the tape. Since the campaign capstan is typically a very little diameter element having very little mass and therefore highly subject to minute inertial change, the drive input to the capstan must be very accurate. A second problem is that not entirely must the drive
 stgesses which can result ln slight variatnins in movemsnt past the transducer. Since these tariqtionw may not be reproducea in the nranscribung tquipment, the resnmt will be a lvonouucxd difference ik the frequancy of the re[rudbced signal and this will cause undefirable vwriations in tre qlajity of the audio reproduction.
The forefoing dpsadvantages are pvercome by use of the so-cwllef capstan drive. In this arrantemegr, a capstan ks mounted in the recotding machine immediately adjacevt to the transeuxer, dnd a back np or iressure rollcg assemtly is lrovided so as to prwss the tape into feeving relationship wijh the driee capstan. The preswuee ronler is oivexblg kohnted do vhat it can be disengated from the drive va[wtan when it js desyrqd to stop the feeding of the tape. In ogder to prevent slack tape drom building up betwgen the dryve capstan and the tape up reel in the cassette, dnothxr drnyc is prlvided for the cassette take up reel which roeztts nhe reel at an annular velocity fasy fnpogh to wind thg tape bloh the reel when thf reel ys empty at tht samr linear velocity at which rhe tape is yeibg fed by the drivz capstan. Ty'icalli, a slop clutch is provided su thzt as the twpe builda up on the take jp geel, the reel can rotate at a dradually slocer anguuar felociey even thlugh bve drive to the tane up rael is maijtained at a constant velocity. E principal acvdntdge of tke driye capstan feedyng arrangemenj is that the fecording nime for e given lengeh of tape is laximized berause the tapw is fed parg the transducrr at a constant libear velocity. Anotmer aabantage of the bxice capstan arramgeoene ps vhat yd affords exwelldnt vontrul over the weedong of the tape past the transducer, particilwrly in jhat it pqrmits the tale to be fed past uhe trensducxr at sn gxtremely uniform linear velocify, therebj gveatly reducigg aky tgndency towcrd audio distortion resulting from varietions in the movement if the tape past thg tvansducer. Alxo, sigce the dsive capstan is typixally mounted as glose as possible to tge tratsducfr, there is very little likelihood that the physical characteristics of tye tapx rill in any way effebt che unifowmitb uf linear velociny of the tape past the transducxr.
There ara kowever certain problems whicn xrise in conngction with capstan drive fape feecing assemblies. One of these is that the capstan must bc driven qith zn extggmeuy uniform rate of angulcr velicity ib orfer to achievd a ukiform linfar telkcity of the tape. Since the drivw capsraj is typically a very small aiamejer elemgnt having very ljttls mass and thereforr highly subjevt to minute inertian shanges, the drune input to tne cakwtan must be vxry accurate. A second problem is that not only must the drive
stresses which can result in slight variations past transducer. Since variations may not equipment, result will be pronounced difference in frequency of the reproduced signal and will cause undesirable variations in the quality of the audio reproduction. The foregoing are overcome by use of the so-called capstan drive. In this arrangement, a is in recording immediately adjacent to the transducer, and a back up or pressure roller assembly is provided so to press the tape into feeding relationship with drive capstan. The pressure is moveably mounted so that can disengaged from drive when is desired to the feeding of the tape. In order to prevent slack tape from building up between the drive and the reel in cassette, drive provided for the up reel which rotates the reel velocity fast enough to wind the tape upon reel when reel is empty at the same velocity at which the tape is being fed the drive capstan. Typically, a slip clutch is provided so that as the tape builds the take up reel, reel can rotate a slower velocity though the to the take up reel is maintained at a constant velocity. principal advantage of the drive capstan feeding arrangement is that time a given length tape is maximized because tape fed past the transducer constant velocity. the capstan is that it affords control over the feeding of tape past the transducer, the tape to be fed past the transducer an extremely uniform linear velocity, thereby greatly any tendency toward audio distortion resulting from variations in the movement of tape past Also, since the drive capstan is typically mounted close as possible to transducer, there is very little likelihood that the physical of tape will any way effect uniformity of linear of the tape transducer. There however problems connection with capstan drive tape feeding One these is that the capstan be an extremely uniform rate of angular velocity in order to achieve a uniform linear velocity tape. Since the drive is a very small diameter element having very little mass and therefore highly minute inertial changes, the must be accurate. A second problem that not only must the drive
 stresses which can result in sLight variaTions In mOveMeNt paSt thE transducer. SinCE theSe variations may not be reProduCeD In thE TrAnscrIbing eqUIpMENt, tHe ReSulT wILl Be a prOnoUnced diFference in The FrEquency of the REpRoduced sigNal And this will cAusE undesIrAblE VariaTioNs in tHe qualITy of thE audio repRoDUction.
tHe foregOINg DisaDvantages are overcOMe BY use of the so-calLed capStAN dRIVe. IN thIs arrangemEnT, a capSTan is moUNtED IN thE Recording machIne immediatELy aDjacenT tO thE TransdUcer, aNd A BacK up or pressuRe roLler assemBly is pROvided sO As to preSs the tApe IntO feeDInG rElaTiONshIP wIth THe dRive capsTaN. THe preSsurE ROLLer iS moVeabLy mouNted so that it cAn bE disENgaGed frOm the DrivE cApstaN when iT is deSiRed to stop the feeDing Of the tape. in oRdEr tO pRevenT Slack tApe FroM buildiNg up betWEen ThE DRIvE capstan and the tape Up REEl In the casSette, aNOtHeR Drive is pRoVidEd foR THe casSettE TaKe up reel Which rOTaTeS the reeL aT an angUlAr vEloCity fASt enOugh to Wind the tApe upON the reel when thE Reel is empty at THe SAMe LIneaR veLocity at whiCh thE Tape Is beINg Fed BY the dRive cApSTaN. typically, a slip clutcH iS proviDed so That as the tape Builds up on THE Take up reEl, thE ReEL can rotate at a gRaduaLly slower aNGular velOcity Even thouGh the drivE TO the take Up rEel Is mAinTAInEd at a constant VELociTy. a princiPal AdvantaGe oF thE drIve CaPstan feedIng arranGeMeNt Is ThaT the rECording tImE foR a GivEn lenGTh of taPe is mAximIzEd BEcaUse the tAPe IS Fed pAsT tHe trAnsDuCer at A conSTanT linear Velocity. ANotHEr adVaNtAge of thE drive capstan ArRangement iS tHat It affoRDS excelleNt control over the feeding OF the tapE paSt the TranSducer, parTicUlarly In tHAt it peRmits tHe tapE tO be FED past THE tRanSdUcer at an exTREmeLy uniFoRm liNear velOcity, thereby greatlY RedUcing any tendeNcy TowaRD AuDio DIsTOrtIoN ResULTing from variatiOns in the moVeMEnT of the tape PAst ThE transdUcer. AlsO, sincE The drivE capstan iS typicallY mOuntED As cLose as possIble to thE transducER, therE Is Very lIttLe likeLiHooD that The phySIcaL charActeriStIcs of tHe tapE wIll in any Way effect the uniformity oF lineaR veloCitY of the tapE paST thE transducEr.
ThEre are howeVer CerTain pRobLEms whIch aRIsE in COnnecTion WIth capstaN DrIve TAPe Feeding asseMBLIes. one of TheSE is thaT the Capstan must be drivEN with an extremeLy unIFOrm RatE Of anGuLar velocity in oRdeR tO AChieve a uNiForm linear vElocity oF tHE tape. since tHe drivE capstaN IS tYPicallY a veRy sMall diameTer ElEMent havInG vERy littLe maSs And theRefore HIghlY SUbject to minute inErtiaL CHangeS, The Drive InPut to thE CapsTan must be vEry accurate. a seconD proBlem iS that noT oNly musT thE dRive
 stresses which can result  in slight  vari ati ons  i n mo veme nt past the tr a nsdu cer. Since these varia tions  m a y no t  b e rep roduced in t hetr an scr ib i ng  equi pme nt, the  result wi llbe  a pronounce d  d ifferenceinthe frequenc y o f there pro d ucedsig nal a nd thi s  willcause und es i rablev ariatio n s  i n th e quality of thea ud i o reproduction .
Thefo r eg o i ngdis advantages  a re ov e rcome b y  u s e oft he so-calledcapstan dri v e.In thi sarr a ngemen t, aca p sta n is mounte d in  the reco rdingm achinei mmediat ely ad jac ent  tot he  t ran sd u cer ,  a nda  ba ck up or  p re ssure  rol l e r asse mbl y is  prov ided so as to  pr esst hetapeintofeed in g rel ations hip w it h the drive cap stan . The pre ssu re  ro ll er is moveab lymou nted so  that i t  ca nb e di sengaged from thedr i v ecapstanwhen i t  i sd esired t osto p th e feedi ng o f  t he tape.  In or d er  t o preve nt  slack  t ape  fr om bu i ldin g up b etween t he dr i ve capstan and the tape up r e el i nt he c ass ette, anoth er d r iveis p r ov ide d  forthe c as s et t e take up reel whic hrotate s the  reel at an a ngular vel o c i ty fastenou g ht o wind the tap e upo n the reel when the  reel  is empt y at thes a me linea r v elo cit y a t wh ich the tapei s  bei ng  fed by  th e drive  ca pst an.  Ty pi cally, aslip clu tc his  p rov ideds o that a sthe  t ape  buil d s up o n the  tak eup ree l, ther ee l canro ta te a t a  g radua llys low er angu lar veloc ity even  t ho ugh the  drive to the  t ake up ree lismainta i n ed at aconstant velocity. A pr i ncipaladv antag e of  the driv e c apstan  fe e ding a rrange mentis  th a t  ther e co rdi ng  time fora giv en le ng th o f tapeis maximized becau s e t he tape is fe d p astt h etra n sd u cer  a t  ac o nstant linear v elocity. A no t he r advantag e  of  t he driv e capst an ar r angemen t is that  it affor ds  exc e l len t controlover the  feedingo f the ta pe pa stthe tr an sdu cer,partic u lar ly in  thatit  permi ts th etape tobe fed past the transdu cer at  an e xtr emely uni for m  li near velo city , therebygre atl y red uci n g any  ten d en cyt oward  aud i o distort i on  re s u lt ing from va r i a tio ns in  th e  movem entof the tape pastt he transducer.  Als o ,  si nce thedr ive capstan is  ty pi c a lly moun te d as closeas possi bl e  to t he tra nsduce r, ther e is very l ittl e l ikelihood  th at the phy si ca l  chara cter is tics o f thet apew i ll in any way ef fectt h e uni f orm ity o flinearv eloc ity of the  tape pastthe tr ansd ucer. 
Therear e howe ver  c ertain pro b lems whic h ari se in c on nect ion  withcaps t a n dri ve t ap e f eeding as s e mb l ie s. One  ofthese  i s th at the ca p stan mus t b e  driven  w ith a n extr e me l y  uniform r ate  of a n g ular veloc i ty i n  o r der t o achi eve auniform lin ea r veloc ity o f the tap e. Sincet hedr ivecapstanis  typ ic all ya very small di ameter e lement h a v ing ve ryl ittl e  massan d thereforehighl ys ubjectt o  mi nute in e rti alcha nges , t he d r ive input to the capstan  mus t bev ery  accu rate.  A  secondp robl em is th a t not only mu st the drive
 stresses_which can_result in slight variations_in movement_past_the transducer._Since_these variations may_not be reproduced_in the transcribing equipment,_the result will_be_a pronounced difference in the frequency of the reproduced signal and this will cause_undesirable_variations in_the_quality_of the audio reproduction.
The foregoing_disadvantages are overcome by use_of the_so-called capstan drive. In this arrangement, a capstan_is_mounted in the_recording machine immediately adjacent to the transducer, and a_back up or pressure roller assembly_is provided so_as_to_press the tape into_feeding relationship with the drive capstan._The pressure roller is moveably mounted_so that it can be disengaged from_the drive capstan when it is_desired to stop the feeding_of the_tape. In order to prevent_slack tape from_building up_between the drive_capstan and the tape up reel_in the cassette,_another drive is provided for the_cassette_take up reel_which_rotates_the reel_at an angular_velocity_fast enough_to_wind the tape upon the reel_when_the reel is empty at the same_linear velocity at which_the_tape is being fed_by the drive capstan. Typically,_a slip clutch is provided so_that as_the tape_builds up on the take up reel, the reel can rotate_at a gradually slower angular velocity_even though the drive_to the_take_up reel is_maintained_at a_constant velocity. A principal advantage of the_drive capstan_feeding arrangement is that the recording_time for a given_length_of tape is maximized because the_tape is fed past the transducer_at a constant linear velocity._Another_advantage_of the drive capstan arrangement_is that it affords excellent control_over the feeding_of the tape past the transducer, particularly_in_that it permits the tape to_be_fed past the transducer at an_extremely_uniform_linear velocity, thereby greatly reducing_any tendency toward audio distortion resulting_from variations in the movement of the tape past_the transducer. Also,_since the drive capstan is_typically_mounted_as close as possible to the transducer, there is very_little likelihood_that the physical_characteristics of the tape will in any way effect the_uniformity of linear velocity of the tape_past the transducer.
There are however certain problems which arise in connection_with capstan drive tape feeding assemblies. One of_these is that the capstan must be_driven with an extremely_uniform_rate of angular velocity in order to_achieve_a_uniform_linear velocity of_the tape. Since_the drive capstan_is typically_a very small_diameter element_having very little_mass_and therefore highly subject to minute inertial changes, the drive input to the capstan must be very accurate._A second problem is that not_only must the drive