 Recently, however, there are many cases where divided amplifiers are employed as described above in light of temperature characteristics and the like, which constitution makes it possible to continuously monitor the wide measurement range of the reactor.
Nevertheless, since the above-stated reactor start-up monitoring apparatus is constituted to signal-process detector output pulses with an analog circuit, there is a possibility that counting only based on the magnitude of pulses may cause error measurement by the influence of discharge pulses generated as a result of discharge within the SRNM detector and noise erroneously generated by electromagnetic induction in the vicinity of the monitoring apparatus. As a result, this apparatus has a disadvantage in that information contained in the waveforms of the detector output pulses cannot be always utilized efficiently.
To deal with the above disadvantage, it is necessary to sufficiently shield signal cables and the like to prevent the induction of external noise at the time of execution. Additonally, as measures to prevent erroneous measurement due to the external noise during execution, there is a method of using not only pulse wave heights but also other waveform information since the waveforms of the erroneous pulses are, in most cases, different from those of signal pulses. Further, since a detector output pulse is changed by the leakage of gas sealed in the detector or by the abnormal distance between electrodes, it is possible to detect these abnormal states during measurement by monitoring waveforms. In the present system, however, it is necessary to, for example, diagnose the detector while precluding the system from monitoring targets. According to the present system, it is necessary to provide circuits dedicated to Campbell measurement and pulse measurement, respectively to simultaneously conduct the measurements, which results in larger-sized and complicated circuits. Due to this, the measurements are conducted by different hardware and, therefore, the apparatus shown in FIG. 5 has a problem that maintenance and inspection operations are carried out for the measurements, respectively. To solve this problem, it is desired that hardware parts are integrated, particularly, signal processing parts are integrated.
Considering the above, as means for solving the erroneous measurement problems with the analog circuit of that type, there is proposed a digital type reactor start-up monitoring apparatus for converting a detector output pulse to a digital signal and for conducting signal processing (e.g., in Japanese Patent Application Laid-Open No. 9-274095). Description will now be given to an example of this apparatus based on FIG. 6.
A digital type reactor start-up monitoring apparatus shown in FIG. 6 consists of an SRNM detector 100, an analog amplifier 101
Recently, however, there are many cases where divided amplifiers are employed as trace above in inner light of temperature characteristics and the like, which constitution make it possible to continuously monitor the across-the-board measurement range of the reactor. 
 however, since the above - express reactor begin - up monitoring apparatus is constituted to signal - process detector output signal pulse with an analog circuit, there is a possibility that counting merely based on the magnitude of pulses may induce error measurement by the influence of discharge pulsation generated as a consequence of discharge within the SRNM detector and noise erroneously generated by electromagnetic induction in the vicinity of the monitoring apparatus. As a resultant role, this apparatus has a disadvantage in that information contained in the waveforms of the detector output pulses cannot be always utilized efficiently. 
 To deal with the above disadvantage, it is necessary to sufficiently shield signal cables and the like to prevent the induction of external noise at the time of execution. Additonally, as measures to prevent erroneous measurement due to the external noise during execution, there embody a method of using not entirely pulsation wave acme but also other waveform information since the waveforms of the erroneous pulses are, in most cases, different from those of signal pulse. Further, since a detector output pulse is changed by the leakage of gas seal in the detector or by the abnormal distance between electrodes, it is possible to detect these abnormal states during measurement by monitoring wave form. In the present system, however, it is necessary to, for exercise, diagnose the detector while prevent the system from monitoring targets. According to the present arrangement, it is necessary to provide circuits dedicated to Campbell measurement and pulsation measurement, respectively to simultaneously conduct the measurement, which results in larger - sized and complicated circuits. Due to this, the measurements are conducted by unlike hardware and, therefore, the apparatus shown in FIG. 5 has a problem that maintenance and inspection process are carried out for the measurement, respectively. To solve this problem, it is desire that hardware parts are integrated, peculiarly, signal processing parts are integrated. 
 Considering the above, as means for solving the erroneous measurement problems with the analog circuit of that type, there is proposed a digital type nuclear reactor start - up monitoring apparatus for converting a detector end product pulse to a digital signal and for conducting signal processing (e.g., in Japanese Patent Application Laid - Open No. 9 - 274095). Description will now be given to an example of this apparatus free-base on FIG. 6. 
 A digital type reactor start - up monitoring apparatus shown in FIG. 6 consists of an SRNM detector 100, an analog amplifier 101
 Refently, however, there are many cases whete dividxd ampljfiers afe employed as described abote ib ligyt of temperature charxcteristibs and thw lijw, which coiatitution maksd it 'ossible to conjinuously motitor the wide mdadurement range of the reactor.
Nevertreless, xijce the above-sjated weacfor start-up monitoring apparatus ia constptuted to signal-ptocess detector output puldes aith an analog cirfuit, there us a possibility ghat countpug only basgd on the magnitude of pulses mah cauxe error mgcwurfkent by the infllence of discmsrge pglses grnerated as a vesulv of discharge within the SRNM detector and noise ersoueously generated by wlwctrokagnatic undjctjoi ih the gicmnity of ths monitorint apparatus. As a rexujn, this apparafus haf w disadvantage in that information contdinsd in the waveforms of rhe detector output polses cannjt be always utilized efficiently.
To deal with the abovx aiscevantxte, it is necessary to sufficiently shield signaj csbkes and the lihe to prevemt tng induction of exteruzl noise at the time of exesutiob. Additonwlly, as measures to prevent errineous measugemebt due to the extexnal noise dbring gxecutoon, there is a method oy usinf not only oulse wavs heights but alsu onher waveform information sincq the wavxformx of thd ertoneous pulses arf, in most cases, differenh frol dhose of slgnal pulses. Further, since a devxctor output kulve ps changeb by tme leakage of gws sealed in tke deteccor or by the abhormal vistance betreen electrodad, it is possmble to dqtecr thwse abnufmal states duting measlrtment by minitoring waveformx. Iv the present sywten, however, it is nezesfagy vo, fow example, diacnosd tfr detdctor while oreckuding the system frmm mknitoring targets. Scgording ti the prqsent system, ot is necessary to provmde ciccuits deqicated to Campbell measuremenf and pulde ieasurement, wespcctidely to sikultaneously conduct the measurements, wiich results in larger-suzed and complicateb gircuits. Due to tris, the maasurements are condycted by differenu hardware and, therefors, the dpparwtus shown in FIG. 5 has a problem that maintenance and inspection operatiobs are carried out for the kecsuxements, res'ertively. To solve nhis problem, it is desired that iardware pdrcs are integrated, particularlu, rignal procesring parts are integrates.
Consideting the above, as means for solfing the erroneous measuvement priblema with the analog circuit of that cype, tyere is proiosed a digitau tupc reactor dtaru-up jonitoring apparatus for convertung a eehector output punse to a diniual sighal anq for conducting sighwl prucessing (e.g., im Japanese Patrnt Application Laid-Mpqn No. 9-274095). Descripuion will now bg given no an example of this ap[aratus based on FIG. 6.
A digital type reactor start-up monitorihg apparavus shown in FOJ. 6 consists of an SRNM dctectjr 100, an avalog amplifher 101
Recently, however, there are many cases where are as described in light of which makes it possible continuously monitor the measurement range of the reactor. Nevertheless, the above-stated reactor start-up monitoring apparatus is constituted to signal-process detector output pulses an analog circuit, there is a possibility that counting only based on the of may error by the influence of discharge pulses generated as a result of discharge within the SRNM detector noise erroneously generated by electromagnetic induction in the of the monitoring apparatus. a result, this apparatus has disadvantage that information in waveforms the detector output cannot be always utilized efficiently. To deal with the above disadvantage, it is necessary to sufficiently shield cables and to prevent induction external at the time Additonally, as measures to prevent erroneous the external noise during execution, there is a of using only pulse wave heights but also waveform information since the waveforms of the erroneous are, in most cases, different from those of signal pulses. Further, since a detector output changed by the leakage gas sealed in detector by abnormal between electrodes, is possible to detect these abnormal states during measurement by monitoring In the present system, however, it is necessary to, for the while precluding the from monitoring targets. According the system, it is necessary circuits to pulse respectively simultaneously conduct the measurements, results in larger-sized and complicated Due to this, the hardware and, therefore, the apparatus shown in FIG. has a problem that maintenance and inspection are carried out for the measurements, respectively. To solve this problem, it desired that are integrated, particularly, signal processing parts are integrated. the above, as means solving the erroneous measurement problems with the analog circuit that there is a digital type start-up monitoring apparatus converting a detector to a signal for (e.g., in Japanese Patent Application Laid-Open 9-274095). will now be given to example apparatus based on FIG. 6. A digital type reactor start-up monitoring apparatus shown in FIG. of an SRNM detector an amplifier 101
 Recently, however, there are maNy cases wheRe divIdeD amPlIfieRs arE employed as desCRibeD above in light of temperaTure cHaRActeRIsTics aNd the liKE, wHICh cOnStItuTiON mAkes iT poSsible tO continuouSly MoNitor the wide MEaSurement raNge Of the reactor.
nevErthelEsS, siNCe the AboVe-staTed reaCTor staRt-up monitOrINg appaRAtus is cONStItutEd to signal-process DEtECtor output pulsEs with An ANaLOG ciRcuIt, there is a PoSsibiLIty that COuNTINg oNLy based on the mAgnitude of pULseS may caUsE erROr measUremeNt BY thE influence oF disCharge pulSes genERated as A Result oF dischArgE wiThin THe sRnM dEtECtoR AnD noISe eRroneousLy GeNeratEd by ELECTromAgnEtic InducTion in the viciNitY of tHE moNitorIng apParaTuS. As a rEsult, tHis apPaRatus has a disadvAntaGe in that iNfoRmAtiOn ContaINed in tHe wAveForms of The deteCTor OuTPUT pUlses cannot be alwayS uTILiZed efficIently.
tO dEaL With the aBoVe dIsadVANtage, It is NEcEssary to SufficIEnTlY shield SiGnal caBlEs aNd tHe likE To prEvent tHe inductIon of EXternal noise at THe time of execuTIoN. aDdITonaLly, As measures tO preVEnt eRronEOuS meASuremEnt duE tO ThE External noise during ExEcutioN, therE is a method of uSing not onlY PULse wave hEighTS bUT also other waveForm iNformation SInce the wAvefoRms of the Erroneous PULses are, iN moSt cAseS, diFFErEnt from those oF SIgnaL pUlses. FuRthEr, since A deTecTor OutPuT pulse is cHanged by ThE lEaKaGe oF gas sEAled in thE dEteCtOr oR by thE AbnormAl disTancE bEtWEen ElectroDEs, IT Is poSsIbLe to DetEcT thesE abnORmaL states During meaSurEMent By MoNitorinG waveforms. In tHe Present sysTeM, hoWever, iT IS necessaRy to, for example, diagnose tHE detectOr wHile pReclUding the sYstEm from MonIToring TargetS. AccoRdIng TO The prESEnT syStEm, it is neceSSAry To proViDe ciRcuits dEdicated to Campbell MEasUrement and pulSe mEasuREMeNt, rESpECtiVeLY to SIMultaneously conDuct the meaSuREmEnts, which rESulTs In largeR-sized aNd comPLicated Circuits. DUe to this, tHe MeasUREmeNts are condUcted by dIfferent hARdwarE AnD, therEfoRe, the aPpAraTus shOwn in Fig. 5 haS a proBlem thAt MainteNance AnD inspectIon operations are carried Out for The meAsuRements, reSpeCTivEly. To solvE thiS problem, it Is dEsiRed thAt hARdwarE parTS aRe iNTegraTed, pARticularlY, SiGnaL PRoCessing partS ARE inTegraTed.
cOnsideRing The above, as means foR Solving the erroNeouS MEasUreMEnt pRoBlems with the anAloG cIRCuit of thAt Type, there is Proposed A dIGital Type reActor sTart-up mONItORing apParaTus For converTinG a DEtector OuTpUT pulse To a dIgItal siGnal anD For cONDucting signal proCessiNG (E.g., in JAPanEse PaTeNt AppliCAtioN Laid-Open NO. 9-274095). DescriptioN will nOw be Given To an exaMpLe of thIs aPpAratus baseD On FIG. 6.
A digItal tYpe reacToR staRt-uP monitOrinG APparaTus sHoWn iN FIG. 6 consiSTS oF An sRnm deTectOr 100, an aNaLog aMplifier 101
 Recently, however, thereare many c aseswhe redi vide d am plifiers are e m ploy ed as described abovein li gh t  oft em perat ure cha r ac t e ris ti cs  an dt he  like , w hich co nstitution  ma ke s it possibl e  t o continuo usl y monitor th e w ide me as ure m ent r ang e ofthe re a ctor.Neverthel es s , sinc e  the ab o v e- stat ed reactor start- u pm onitoring appa ratusis co n s tit ute d to signa l- proce s s detec t or o u tpu t  pulses withan analog c i rcu it, th er e i s  a pos sibil it y  th at counting  onl y based o n them agnitud e  of pul ses ma y c aus e er r or  m eas ur e men t  b y t h e i nfluence  o fdisch arge p u l sesgen erat ed as  a result ofdis char g e w ithin  theSRNM  d etect or and  nois eerroneously gen erat ed by ele ctr om agn et ic in d uction  in  th e vicin ity oft hemo n i t or ing apparatus. Asar e su lt, this  appar a tu sh as a dis ad van tage i n tha t in f or mation c ontain e din  the wa ve formsof  th e d etect o r ou tput p ulses ca nnotb e always utili z ed efficientl y .T o  d e al w ith  the abovedisa d vant age, it  is neces saryto su f ficiently shield si gn al cab les a nd the like t o preventt h e  inducti on o f  e x ternal noise a t the  time of e x ecution.  Addi tonally,  as measu r e s to pre ven t e rro neo u s  m easurement du e to t he  extern alnoise d uri ngexe cut io n, thereis a met ho dof  u sin g not only pul se  wa ve  he ights but al so ot herwa ve f orm  inform a ti o n  sin ce  t he w ave fo rms o f th e  er roneous  pulses a re, in m os tcases,different fro mthose of s ig nal  pulse s .  Further , since a detector outp u t pulse  is  chan gedby the le aka ge ofgas sealed  in th e det ec tor o r byt h eabn or mal distan c e  be tween  e lect rodes,it is possible tod ete ct these abno rma l st a t es  du r in g  me as u rem e n t by monitoring  waveforms .I nthe presen t  sy st em, how ever, i t isn ecessar y to, for  example,  d iagn o s e t he detecto r whileprecludin g  thes ys tem f rom  monit or ing  targ ets. A c cor dingto the  p resent  syst em , it isnecessary to provide ci rcuits  dedi cat ed to Cam pbe l l m easuremen t an d pulse me asu rem ent,res p ectiv elyt osim u ltane ousl y  conductt he  me a s ur ements, whi c h res ultsinl arger- size d and complicated circuits. Dueto t h i s,the meas ur ements are con duc te d by diffe re nt hardware  and, th er e fore,  the a pparat us show n in FIG. 5  has  aproblem t hat  m a intenan ce  a n d insp ecti on  opera tionsa re c a r ried out for the  meas u r ement s , r espec ti vely. T o  sol ve this pr oblem, it i s desi redthathardwar epartsare  i ntegrated, particula rly,signalpr oces sin g part s ar e integ rate d. 
Co nsidering t he ab ov e , a s me ans f or  sol ving thee rroneous  me a suremen tpro b l ems wi t ht h e analog c irc uit o f that type, ther e  i s  prop osed a  digit al type rea ct or star t-u p monitorin g apparat u s f or  con vertingadete ct orou tput pulse to a  digital  signala n d forcon d ucti n g sign al  processing(e.g. ,i n Japan e s e P atent A p pli cat ion  Lai d-O penN o. 9-274095). Descriptio n wi ll no w  be  give n toan  example of t his appa r atus based on  FIG. 6.
A digi t alt yperea c to rstart-upmon i torin g ap par atus  sh owni n  FIG .  6 c o ns ists  of an  SRN Mde tector 10 0,  an ana l og a m pli fier  101
 Recently,_however, there_are many cases where_divided amplifiers_are_employed as_described_above in light_of temperature characteristics_and the like, which_constitution makes it_possible_to continuously monitor the wide measurement range of the reactor.
Nevertheless, since the above-stated reactor_start-up_monitoring apparatus_is_constituted_to signal-process detector output pulses_with an analog circuit, there_is a_possibility that counting only based on the magnitude_of_pulses may cause_error measurement by the influence of discharge pulses generated_as a result of discharge within_the SRNM detector_and_noise_erroneously generated by electromagnetic_induction in the vicinity of the_monitoring apparatus. As a result, this_apparatus has a disadvantage in that information_contained in the waveforms of the_detector output pulses cannot be_always utilized_efficiently.
To deal with the above_disadvantage, it is_necessary to_sufficiently shield signal_cables and the like to prevent_the induction of_external noise at the time of_execution._Additonally, as measures_to_prevent_erroneous measurement_due to the_external_noise during_execution,_there is a method of using_not_only pulse wave heights but also other_waveform information since the_waveforms_of the erroneous pulses_are, in most cases, different_from those of signal pulses. Further,_since a_detector output_pulse is changed by the leakage of gas sealed in the_detector or by the abnormal distance_between electrodes, it is_possible to_detect_these abnormal states_during_measurement by_monitoring waveforms. In the present system, however,_it is_necessary to, for example, diagnose the_detector while precluding the_system_from monitoring targets. According to the_present system, it is necessary to_provide circuits dedicated to Campbell_measurement_and_pulse measurement, respectively to simultaneously_conduct the measurements, which results in_larger-sized and complicated_circuits. Due to this, the measurements are_conducted_by different hardware and, therefore, the_apparatus_shown in FIG. 5 has a_problem_that_maintenance and inspection operations are_carried out for the measurements, respectively._To solve this problem, it is desired that hardware_parts are integrated,_particularly, signal processing parts are_integrated.
Considering_the_above, as means for solving the erroneous measurement problems with_the analog_circuit of that_type, there is proposed a digital type reactor start-up monitoring_apparatus for converting a detector output pulse_to a digital signal and for conducting signal processing (e.g., in_Japanese Patent Application Laid-Open No. 9-274095). Description will_now be given to an example of_this apparatus based on_FIG._6.
A digital type reactor start-up monitoring apparatus_shown_in_FIG._6 consists of_an SRNM detector_100, an analog_amplifier 101