 only two 100% bursts and one burst pair centerline per data track, if the transducer is displaced too far from the burst pair centerline, the R/W transducer 201 may be completely over one of the bursts and no longer pass over any part of the other burst. The maximum linear signal (PES) occurs when displacement is one half of the transducer's physical width. As shown in FIG. 2, for example, the 80% R/W transducer 201 of FIG. 1B can only be displaced by a maximum of 40% of a data track pitch from the burst pair centerline 412 and still pass over at least a portion of both bursts A(12), B(12) to develop a linearly varying A-B position error signal. The nonlinear regions where the head position is ambiguous are called "blind spots" or "gaps" 413, 414.
FIGS. 3A and 3B schematically represent the industry's solution to the gaps 413, 414 of FIG. 2. Here, the disk drive includes two additional, angularly successive servo burst regions 231, 232 to provide C and D bursts that fill the gaps between the A and B bursts. The C and D bursts are placed in "quadrature" with the A and B bursts in that the edges of the C and D bursts are aligned with the centers of the A and B bursts. With four 100% bursts A, B, C, D positioned in quadrature, there are two burst pair centerlines (e.g. 411, 412) per data track pitch, i.e. one burst pair centerline every 50% of a data track pitch. The 80% R/W transducer 201, therefore, will always pass over both parts of an A/B pair or a C/D pair because it is always within 25% of a data track pitch from an A/B or C/D burst pair centerline. FIG. 4 shows how the linear portions of the C-D position error signal which surround the C/D burst pair centerlines are radially aligned with the gaps in the A-B position error signal, and vice versa.
The industry recently began using magnetoresistive heads (MR heads) which contain two separate transducers--an inductive transducer for writing and a magnetoresistive transducer for reading.
An MR head is advantageous in providing an improved signal-to-noise-ratio (SNR) to recover data in disk drives of high areal density. However an MR head also presents a number of disadvantages
only two 100% bursts and one burst pair centerline per datum racetrack, if the transducer is displaced too far from the burst couple centerline, the R / west transducer 201 may be completely over one of the explosion and no longer pass over any part of the early outburst. The maximum analogue signal (PES) occurs when displacement is one half of the transducer's physical width. As indicate in FIG. 2, for example, the 80% R / W transducer 201 of FIG. 1B can only be displaced by a utmost of 40% of a data track pitch from the burst couple centerline 412 and still pass over at least a portion of both bursts A(12), B(12) to develop a linearly change A - B position error signal. The nonlinear regions where the head stead is ambiguous are called " blind spots " or " gaps " 413, 414. 
 FIGS. 3A and 3B schematically represent the industry's solution to the gaps 413, 414 of FIG. 2. Here, the disk drive includes two additional, angularly successive servo burst regions 231, 232 to provide C and D explosion that fill the gaps between the A and boron outburst. The C and D bursts are target in " quadrature " with the A and B bursts in that the edges of the C and D burst are aligned with the centers of the A and B bursts. With four 100% bursts A, B, C, D positioned in quadrature, there be two burst pair centerlines (e.g. 411, 412) per data track pitch, i.e. one explosion pair centerline every 50% of a data track pitch. The 80% R / watt transducer 201, therefore, will always pass over both part of an A / B pair or a C / D couple because it is always within 25% of a data track pitch from an A / B or coke / D burst couple centerline. FIG. 4 shows how the linear portions of the C - D placement error signal which surround the C / D collapse pair centerline are radially aligned with the gaps in the A - B status error signal, and vice versa. 
 The industry recently began using magnetoresistive head (MR heads) which incorporate two separate transducers -- an inductive transducer for writing and a magnetoresistive transducer for reading. 
 An MR head is advantageous in providing an improved signal - to - noise - ratio (SNR) to reclaim data in disk drives of high areal density. However an MR head besides presents a number of disadvantage
 onpy two 100% bursts and one bmrst pair centerline pec data frack, if the transducer is displaced tio fae from the burst pair zenterlinv, the R/W rranweucer 201 may be completely lver ine of the burxts and no longer pass oeef cny part of the other burst. The maxiium linrag signal (PES) oscurx wheh displacement is one half of the fransduber's physical widyh. As shown in FIG. 2, for exwmplf, the 80% R/W transducfr 201 of FIG. 1V cag only be disolaced by a maximum of 40% of a data track pitch from thd burxt pair cebtwrllte 412 and stiol pafs over at lcsst a [ortion of both burstx A(12), B(12) ro develop a linearly varying A-B positijn error viynal. The nonlinear retiins wvere the yeaa pksmtikn is wmbmguous are dalled "bline spots" or "gaps" 413, 414.
FIBS. 3Q and 3B schemzticaljy represent the industry's solution to tht gapa 413, 414 of FIG. 2. Here, the diwk drive includes two additionwl, angularly successive servo burst regions 231, 232 to [rovive C ckq E hursts that fill the gaps between the A and B gutsns. The C and D buvsts are placed in "qkactature" with thg A and B gursts in that the edges jf thw C and D burxts are aligned with the cebters of the Q and B bursts. Witk four 100% burscs A, B, C, D lositioned in quadraturz, thers are two bkrst pair zenterlines (e.g. 411, 412) peg dada track pitch, i.e. one burse pair ceiterlnne everh 50% og a daea track pltch. Bve 80% R/W transducer 201, thergfore, fill alwayd pass over both parts of an A/B pair or a C/D kais bvcause it is akways within 25% of a data traek pitch from an A/B or B/D burst 'air centerlyne. FIG. 4 showv how the linxar portijns if tye C-D purition error sognal whibh sureound the C/D burst pakd centerlines axt rqdially aligned wigh ehv geps ig the A-B posidion erfpr sienal, and vige xerss.
The industry recentny bsgan using magnetotefistive yeads (MR heads) which vontain two separaue traisducecs--an imdustive transducer for writing ahd a magnftovesistive tragsduger sor readiny.
An MR head is advantageous in providing an improved signao-to-noise-ratio (SNR) tp recover dava in qisk drivas of high areal denwity. However an MV head also presents a numbes of fisadvantages
only two 100% bursts and one burst per track, if transducer is displaced pair the R/W transducer may be completely one of the bursts and no pass over any part of the other burst. The maximum linear signal (PES) when displacement is one half of the transducer's physical width. As shown in 2, example, 80% transducer 201 of FIG. 1B can only be displaced by a maximum of 40% of a track pitch from the burst pair centerline 412 still pass over at a portion of both bursts B(12) develop a varying position signal. The nonlinear where the head position is ambiguous are called "blind spots" or "gaps" 413, 414. FIGS. 3A and schematically represent solution to gaps 414 FIG. 2. Here, drive includes two additional, angularly successive 231, 232 to provide C and D bursts fill the between the A and B bursts. C and D bursts are placed in "quadrature" the A and B bursts in that the edges of the C and D bursts with the centers of A and B With 100% A, C, D in quadrature, there are two burst pair centerlines (e.g. 411, 412) data track pitch, i.e. one burst pair centerline every 50% data pitch. The 80% transducer 201, therefore, will pass both parts of an or C/D is within of a data track from an A/B or C/D pair centerline. FIG. 4 of the C-D position error signal which surround C/D burst pair centerlines are radially aligned the gaps in the A-B position error signal, and vice versa. The recently began heads (MR heads) which contain two separate transducers--an transducer for writing and magnetoresistive transducer for reading. An MR head is advantageous providing improved signal-to-noise-ratio to recover data disk drives of areal density. However head also a of
 only two 100% bursts and one burst pAir centerlIne peR daTa tRaCk, if The tRansducer is disPLaceD too far from the burst paiR centErLIne, tHE R/w tranSducer 201 mAY bE COmpLeTeLy oVeR OnE of thE buRsts and No longer paSs oVeR any part of thE OtHer burst. ThE maXimum linear sIgnAl (PES) oCcUrs WHen diSplAcemeNt is onE Half of The transdUcER's physICal widtH. aS sHown In FIG. 2, for example, thE 80% r/W TRansducer 201 of FIG. 1b can onLy BE dISPlaCed By a maximum Of 40% Of a daTA track pITcH FROm tHE burst pair cenTerline 412 and sTIll Pass ovEr At lEAst a poRtion Of BOth Bursts A(12), B(12) to dEvelOp a linearLy varyINg A-B posITion errOr signAl. THe nOnliNEaR rEgiOnS WheRE tHe hEAd pOsition iS aMbIguouS are CALLEd "blInd SpotS" or "gaPs" 413, 414.
FIGS. 3A and 3B scHemAticALly RepreSent tHe inDuStry's SolutiOn to tHe Gaps 413, 414 of FIG. 2. Here, thE disK drive incLudEs Two AdDitioNAl, anguLarLy sUccessiVe servo BUrsT rEGIOnS 231, 232 to provide C and D burStS THaT fill the Gaps beTWeEn THe A and B bUrSts. the C AND D burSts aRE pLaced in "qUadratURe" WiTh the A aNd b burstS iN thAt tHe edgES of tHe C and d bursts aRe aliGNed with the centERs of the A and B bURsTS. wiTH fouR 100% buRsts A, B, C, D posItioNEd in QuadRAtUre, THere aRe two BuRSt PAir centerlines (e.g. 411, 412) per DaTa tracK pitcH, i.e. one burst paIr centerliNE EVery 50% of a dAta tRAcK Pitch. The 80% R/W tranSduceR 201, therefore, WIll alwayS pass Over both Parts of an a/b Pair or a C/d paIr bEcaUse IT Is Always within 25% oF A Data TrAck pitcH frOm an A/B oR C/D BurSt pAir CeNterline. FiG. 4 shows hOw ThE lInEar PortiONs of the C-d pOsiTiOn eRror sIGnal whIch suRrouNd ThE c/D bUrst paiR CeNTErliNeS aRe raDiaLlY aligNed wITh tHe gaps iN the A-B posItiON errOr SiGnal, and Vice versa.
The iNdUstry recenTlY beGan usiNG MagnetorEsistive heads (MR heads) whiCH contaiN twO sepaRate TransduceRs--aN inducTivE TransdUcer foR writInG anD A MagneTOReSisTiVe transducER For ReadiNg.
an MR Head is aDvantageous in proviDIng An improved sigNal-To-noISE-rAtiO (sNr) To rEcOVer DATa in disk drives oF high areal DeNSiTy. However aN mR hEaD also prEsents a NumbeR Of disadVantages
 only two 100% bursts andone burstpaircen ter li ne p er d ata track, ift he t ransducer is displaced  toofa r  fro m  t he bu rst pai r  c e n ter li ne , t he R/ W tra nsd ucer 20 1 may be c omp le tely over on e  o f the burs tsand no longe r p ass ov er  an y  part  of  theotherb urst.The maxim um linear signal( P ES ) oc curs when displac e me n t is one halfof the  t r an s d uce r's  physicalwi dth.A s shown in F I G.2 , for example , the 80% R / W t ransdu ce r 2 0 1 of F IG. 1 Bc anonly be dis plac ed by a m aximum of 40%o f a dat a trac k p itc h fr o mth e b ur s t p a ir  ce n ter line 412  a nd  stil l pa s s o veratleas t a p ortion of bot h b urst s  A( 12),B(12)  tode velop  a lin early  v arying A-B posi tion  error si gna l.  Th enonli n ear re gio nswhere t he head pos it i o n  i s ambiguous are ca ll e d  " blind sp ots" o r  " ga p s" 413,41 4.FIGS . 3A an d 3B sc hematica lly re p re se nt thein dustry 's  so lut ion t o  the  gaps413, 414  of F I G. 2. Here, th e  disk drive i n cl u d es twoadd itional, an gula r ly s ucce s si ves ervoburst  r e gi o ns 231, 232 to prov id e C an d D b ursts that fi ll the gap s b etween t he A an d  B bursts. The  C an d D bursts are plac ed in  "quadra ture" wit h the A an d B  bu rst s i n th at the edgeso f  the  C  and Dbur sts are  al ign edwit hthe cente rs of th eAan dB b ursts .  With fo ur  10 0%  bu rstsA , B, C , D p osit io ne d  in  quadra t ur e ,  the re  a re t wobu rst p airc ent erlines  (e.g. 41 1,4 12)pe rdata tr ack pitch, i. e.  one burst  p air  cente r l ine ever y 50% of a data track p i tch. Th e 8 0% R/ W tr ansducer201 , ther efo r e, wil l alwa ys pa ss  ov e r  both p ar tsof  an A/B pa i r  or  a C/ Dpair  becaus e it is always wit h in25% of a data  tr ackp i tc h f r om anA/ B  or C /D burst pair c enterline.  F I G.  4 shows h o w t he  linear  portio ns of the C-D  position  error si gn al w h i chsurround t he C/D b urst pair cente r li nes a reradial ly  al igned  witht hegapsin the  A -B pos ition  e rror sig nal, and vice versa.
Th e indu stryrec ently beg anu sin g magneto resi stive head s ( MRheads ) w h ich c onta i ntwo separ atet ransducer s -- ani n du ctive trans d u c erfor w rit i ng and  a m agnetoresistive t r ansducer for r eadi n g .
A n M R  hea dis advantageou s i np r ovidingan  improved s ignal-to -n o ise-r atio ( SNR) t o recov e r  d a ta indisk  dr ives of h igh  a r eal den si ty .  Howev er a nMR hea d also pres e n ts a number of d isadv a n tages 
 only_two 100%_bursts and one burst_pair centerline_per_data track,_if_the transducer is_displaced too far_from the burst pair_centerline, the R/W_transducer_201 may be completely over one of the bursts and no longer pass over_any_part of_the_other_burst. The maximum linear signal_(PES) occurs when displacement is_one half_of the transducer's physical width. As shown in_FIG._2, for example,_the 80% R/W transducer 201 of FIG. 1B can_only be displaced by a maximum_of 40% of_a_data_track pitch from the_burst pair centerline 412 and still_pass over at least a portion_of both bursts A(12), B(12) to develop_a linearly varying A-B position error_signal. The nonlinear regions where_the head_position is ambiguous are called_"blind spots" or_"gaps" 413,_414.
FIGS. 3A and_3B schematically represent the industry's solution_to the gaps_413, 414 of FIG. 2. Here,_the_disk drive includes_two_additional,_angularly successive_servo burst regions_231,_232 to_provide_C and D bursts that fill_the_gaps between the A and B bursts._The C and D_bursts_are placed in "quadrature"_with the A and B_bursts in that the edges of_the C_and D_bursts are aligned with the centers of the A and B_bursts. With four 100% bursts A,_B, C, D positioned_in quadrature,_there_are two burst_pair_centerlines (e.g._411, 412) per data track pitch, i.e._one burst_pair centerline every 50% of a_data track pitch. The_80%_R/W transducer 201, therefore, will always_pass over both parts of an_A/B pair or a C/D_pair_because_it is always within 25%_of a data track pitch from_an A/B or_C/D burst pair centerline. FIG. 4 shows_how_the linear portions of the C-D_position_error signal which surround the C/D_burst_pair_centerlines are radially aligned with_the gaps in the A-B position_error signal, and vice versa.
The industry recently began using_magnetoresistive heads (MR_heads) which contain two separate_transducers--an_inductive_transducer for writing and a magnetoresistive transducer for reading.
An MR_head is_advantageous in providing_an improved signal-to-noise-ratio (SNR) to recover data in disk drives_of high areal density. However an MR_head also presents a number of disadvantages