β from the measured initial phase β.
In this distance measuring device, prior to a distance measurement, the distance measuring device is actuated to carry out preliminary sampling to sample a few cycles of the intermediate frequency signal IF preliminarily. This is carried out to detect sampling positions at the maximum level Amax and the minimum level Amin within one-cycle range of the intermediate frequency signal IF and to thereby simplify the subsequent detection of the amplitude Ai. In addition, in order to obtain frequency distribution of the amplitude Ai, the amplitude range is divided into a plurality of grades, and a storage area to hold frequencies of the respective grades is prepared in the memory 46.
Then, a distance measurement is started, and every time one cycle of the intermediate frequency signal IF has been detected, the synthetic data S (FIG. 3) for which sampling data at the same phase position has been added is stored in the memory 46, and based on ½ of a difference in levels between the sampling positions that have indicated the maximum level Amax and the minimum level Amin determined from the result of the preliminary sampling prior to the distance measurement, a grade of the amplitude Ai of the intermediate frequency signal IF is determined, 1 is added to the frequency of that grade, and frequency distribution of the amplitude Ai is also stored in the memory 46. After completion of the sampling, the initial phase β is determined by use of the synthetic sine wave S′ of the intermediate frequency signal IF, and by use of the frequency distribution of the amplitude Ai, the weighted average Σ{Ai·Δφi(Ai)}/ΣAi obtained by weighting the correction amount Δφi(Ai) with the amplitude Ai of the intermediate frequency signal IF, namely, the correction amount Δβ is calculated. Then, the correction amount Δβ is subtracted from the initial phase β to calculate a distance to the target 22.
As a matter of course, in this distance measuring device as well, the distance measuring light L can be switched to a reference light R that leads to the light receiving element 28 through an internal light path including a diaphragm 27a. By carrying out a distance measurement by use of the reference light R, the distance determined by use of the foregoing distance measuring light L can be corrected. Such a device is disclosed in Japanese Published Unexamined Patent Application No. 2004-264116.
In such a distance measuring device, since the distance has been calculated after consecutively sampling the intermediate frequency signal IF for more than a few thousands of a large number
β from the measured initial phase β. 
 In this distance measuring device, prior to a distance measurement, the distance measuring device is actuated to hold out preliminary sample distribution to sample a few cycles of the intermediate frequency signal IF preliminarily. This is impart out to detect sample positions at the maximum level Amax and the minimal horizontal surface Amin within one - cycle scope of the intermediate frequency signal IF and to thereby simplify the subsequent detection of the amplitude Ai. In summation, in order to obtain frequency distribution of the amplitude Ai, the amplitude image is separate into a plurality of grade, and a storage area to defy frequencies of the respective grades is organize in the memory 46. 
 Then, a distance measurement is started, and every time one cycle of the intermediate frequency signal IF has been detect, the synthetic datum S (FIG. 3) for which sampling data at the same phase position has been add is stored in the memory 46, and based on ½ of a difference in levels between the sampling position that have indicated the maximum level Amax and the minimum level Amin determined from the result of the preliminary sampling prior to the distance measurement, a grade of the amplitude Ai of the intermediate frequency signal IF is determine, 1 is added to the frequency of that grade, and frequency distribution of the amplitude Ai is besides store in the memory 46. After completion of the sample distribution, the initial phase β is determined by use of the synthetic sine wave S′ of the intermediate frequency signal IF, and by use of the frequency distribution of the amplitude Ai, the weighted average Σ{Ai·Δφi(Ai)}/ΣAi obtained by burden the correction amount Δφi(Ai) with the amplitude Ai of the intermediate frequency signal IF, namely, the correction amount Δβ is calculated. Then, the discipline amount Δβ is subtracted from the initial phase β to calculate a distance to the target 22. 
 As a matter of course, in this distance measuring device equally well, the distance measure light L can be switched to a reference inner light R that leads to the light get element 28 through an internal light path admit a diaphragm 27a. By carrying out a distance measurement by consumption of the reference light roentgen, the distance determined by function of the foregoing distance measure light lambert can be corrected. Such a device is disclosed in Japanese publish Unexamined Patent Application nobelium. 2004 - 264116. 
 In such a distance measuring device, since the distance has been calculated after consecutively sampling the average frequency signal IF for more than a few thousands of a large number
β frlm the measured initial khase β.
In this disjabce meesuring device, orior to a distance measuremxnt, rhe dustance measuring devize is actlated to xarrb out preliminarb sampliky to awmplz e few cycles of the interkediate frequetch dignal IF preliminarily. This is carwied ouy ho detect sampjing [osifpoks at the maximum level Amax and the miiimum level Amim within one-cycle range of the intermediate freqkency signao IF qnd to therecy simplifj the subsesuent detection of the amplitudd Ai. Nn addition, ib ogger to obtamn frezuency distrlnution of the amplitude Ai, bhe akplutude range is dividev into a plurality os grades, dnb a storage area to hile frexuenwies if ghe rxspsctive gredes is prelared in thw memory 46.
Then, a disuansv measurement is stwreed, and every time one cycle of the inttrmedjate frequency signal ID has been detected, tje syntheeic data S (FIG. 3) for which sampling data at the sake phesd pisltiov hws been added is stored in the memory 46, and bafsd ok ½ of a differenge in levels betwern tng sampling posktions thzt have indicated hhe maxymum oevel Amav anc the minimum level Amin derermined froi the result of the preliminarv sampking lrior to the distance mzasurejent, a gradf of the zoplitude Ai of tfe pntesmediate frequency signal YF is detxrminzd, 1 is aaded to thq frequencj of bvat grade, and freqkency dhstributioj of the amplitude Ai is also svpred in the kekorj 46. After eomplebion of the sam[ling, the initnal phasz β is aetermined by use of the synehetic sine wdge S′ of the mntermediwte dreqyency skenal IF, and by use of tkt frequenct distribution of bhe aollitude Ai, the ctigyted average Σ{Ai·Δφo(Ai)}/ΣXi jbnaiied br weighting tve currdvtion amount Δφi(Ai) dith the amplitude Ai of the intermediate freqiekcy signao IF, namqly, the correvtion amount Δβ is cwlculeted. Tien, thr cjrrection amount Δβ is subtractes from thf ikitial phase β to galcolate a discance to the target 22.
As a matter of coursx, in this distance measyring device as welk, the distanre meafuring licht L can be switchee to a reference kight R that leads to the lhght geceiving element 28 through an internal light path including a diaphragm 27a. By cacrring out a sistsnce kecsuxement fy udx of the referencv light R, the distance determinev by use ox che foregoing distance measurone light L can be corrected. Such a devjce is dosclosed in Japanese Published Inexamined Patent Applicstion No. 2004-264116.
In shch a distence measuring devicr, sincz the eistancw had been calculxtec wfter condecuuivemy sampling the intermediate frewuency slgnal IF for morx than a few uhousanss of w large number
β from the measured initial phase β. distance device, prior a distance measurement, actuated carry out preliminary to sample a cycles of the intermediate frequency signal preliminarily. This is carried out to detect sampling positions at the maximum level and the minimum level Amin within one-cycle range of the intermediate frequency signal and thereby the detection of the amplitude Ai. In addition, in order to obtain frequency distribution of the amplitude the amplitude range is divided into a plurality grades, and a storage to hold frequencies of the grades prepared in memory Then, distance measurement is and every time one cycle of the intermediate frequency signal IF has been detected, the synthetic data (FIG. 3) sampling data the phase has been added in the memory 46, and based a difference in levels between the sampling positions have indicated maximum level Amax and the minimum Amin determined from the result of the preliminary prior to the distance measurement, a grade of the amplitude Ai of the intermediate frequency is determined, 1 is to the frequency that and distribution the amplitude is also stored in the memory 46. After completion of the the initial phase β is determined by use of the wave of the intermediate signal IF, and by of frequency distribution of the the average weighting correction Δφi(Ai) with the amplitude of the intermediate frequency signal namely, the correction amount correction amount Δβ is subtracted from the initial β to calculate a distance to the 22. As a matter of course, in this distance measuring device as the distance L can be switched to a reference light that leads to the receiving element 28 through an internal light path including diaphragm By carrying a distance measurement use of the light R, the by use the distance can be corrected. Such a device disclosed Japanese Published Unexamined Patent Application 2004-264116. a distance measuring device, since the distance has been calculated after consecutively sampling the intermediate IF for more than few of a large number
β from the measured initial phAse β.
In this DistaNce MeaSuRing DeviCe, prior to a distANce mEasurement, the distance mEasurInG DeviCE iS actuAted to cARrY OUt pReLiMinArY SaMplinG to Sample a Few cycles oF thE iNtermediate fREqUency signaL IF PreliminarilY. ThIs is caRrIed OUt to dEteCt samPling pOSitionS at the maxImUM level aMax and tHE MiNimuM level Amin within oNE-cYCle range of the iNtermeDiATe FREquEncY signal IF aNd To theREby simpLIfY THE suBSequent detectIon of the ampLItuDe Ai. In AdDitIOn, in orDer to ObTAin Frequency diStriBution of tHe amplITude Ai, tHE amplitUde ranGe iS diVideD InTo A plUrALitY Of GraDEs, aNd a storaGe ArEa to hOld fREQUEnciEs oF the RespeCtive grades is PrePareD In tHe memOry 46.
ThEn, a dIsTance MeasurEment Is Started, and every Time One cycle oF thE iNteRmEdiatE FrequeNcy SigNal IF haS been deTEctEd, THE SyNthetic data S (FIG. 3) for WhICH sAmpling dAta at tHE sAmE Phase posItIon Has bEEN addeD is sTOrEd in the mEmory 46, aND bAsEd on ½ of a DiFferenCe In lEveLs betWEen tHe sampLing posiTions THat have indicatED the maximum leVEl aMAx ANd thE miNimum level AMin dETermIned FRoM thE ResulT of thE pRElIMinary sampling prior To The disTance Measurement, a gRade of the aMPLItude Ai oF the INtERmediate frequeNcy siGnal IF is deTErmined, 1 iS addeD to the frEquency of THAt grade, aNd fReqUenCy dISTrIbution of the aMPLituDe ai is alsO stOred in tHe mEmoRy 46. AFteR cOmpletion Of the samPlInG, tHe IniTial pHAse β is deTeRmiNeD by Use of THe syntHetic Sine WaVe s′ Of tHe interMEdIATe frEqUeNcy sIgnAl iF, and By usE Of tHe frequEncy distrIbuTIon oF tHe AmplituDe Ai, the weightEd Average Σ{Ai·δφI(Ai)}/σAi obtAINed by weiGhting the correction amouNT Δφi(Ai) wIth The amPlitUde Ai of thE inTermedIatE FrequeNcy sigNal IF, NaMelY, THe corRECtIon AmOunt Δβ is caLCUlaTed. ThEn, The cOrrectiOn amount Δβ is subtraCTed From the initiaL phAse β TO CaLcuLAtE A diStANce TO The target 22.
As a matTer of coursE, iN ThIs distance MEasUrIng deviCe as welL, the dIStance mEasuring lIght L can bE sWitcHED to A reference Light R thAt leads to THe ligHT rEceivIng ElemenT 28 tHroUgh an InternAL liGht paTh inclUdIng a diAphraGm 27A. By carryIng out a distance measuremEnt by uSe of tHe rEference lIghT r, thE distance DeteRmined by usE of The ForegOinG DistaNce mEAsUriNG lighT L caN Be correctED. SUch A DEvIce is discloSED In JApaneSe PUBlisheD UneXamined Patent ApplICation No. 2004-264116.
In such A disTANce MeaSUrinG dEvice, since the dIstAnCE Has been cAlCulated afteR consecuTiVEly saMpling The intErmediaTE FrEQuency SignAl If for more tHan A fEW thousaNdS oF A large NumbEr
β from the measured initia l phase β. 
In t his  di st ance  mea suring device, prio r to a distance measur ement ,t he d i st ancemeasuri n gd e vic eis  ac tu a te d tocar ry outpreliminar y s am pling to sam p le  a few cyc les  of the inte rme diatefr equ e ncy s ign al IF  preli m inaril y. This i sc arried out tod e te ct s ampling positions at the maximum le vel Am ax an d the  mi nimum leve lAminw ithin o n e- c y c ler ange of the i ntermediate fre quency  s ign a l IF a nd to  t h ere by simplify  the  subseque nt det e ction o f  the am plitud e A i.In a d di ti on,  i n  or d er  to obt ain freq ue nc y dis trib u t i o n of  th e am plitu de Ai, the am pli tude ran ge is  divi dedin to aplural ity o fgrades, and a s tora ge area t o h ol d f re quenc i es ofthe  re spectiv e grade s  is  p r e p ar ed in the memory 4 6. T he n, a dis tancem ea su r ement is  s tar ted, a nd ev eryt im e one cy cle of th einterme di ate fr eq uen cysigna l  IFhas be en detec ted,t he synthetic d a ta S (FIG. 3) fo r wh i ch s amp ling data a t th e  sam e ph a se  po s ition  hasbe e na dded is stored in t he  memor y 46,  and based on  ½ of a di f f e rence in  lev e ls between the sa mplin g position s  that ha ve in dicatedthe maxim u m  level A max  an d t hem i ni mum level Ami n dete rm ined fr omthe res ult  of  th e p re liminarysampling  p ri or  t o t he di s tance me as ure me nt,  a gr a de ofthe a mpli tu de Aiof thei nt e r medi at efreq uen cy  sign al I F  is  determ ined, 1 i s a d dedto  t he freq uency of that  g rade, andfr equ ency d i s tributio n of the amplitude Ai i s  also s tor ed in  the  memory 4 6.Aftercom p letion  of th e sam pl ing , the i n i ti alph ase β is d e t erm inedby  use  of the  synthetic sine wa v e S ′ of the inte rme diat e fr equ e nc y  si gn a l I F ,  and by use ofthe freque nc y  d istributio n  of  t he ampl itude A i, th e  weight ed averag e Σ{Ai·Δφ i( Ai)} / Σ Aiobtained b y weight ing the c o rrect i on  amou ntΔφi(Ai )wit h the  ampli t ude  Ai o f thein termed iatefr equencysignal IF, namely, thecorrec tionamo unt Δβ is  ca l cul ated. The n, t he correct ion  am ountΔβi s sub trac t ed  fr o m the  ini t ial phase βtoc a lc ulate a dis t a n ceto th e t a rget 2 2.
A s a matter of cou r se, in this di stan c e  me asu r ingde vice as well,the  d i s tance me as uring light  L can b es witch ed toa refe rence l i g ht R that  lea dsto the li ght  r e ceiving  e le m ent 28  thr ou gh anintern a l li g h t path including  a di a p hragm 27a . Byca rryingo ut a  distancemeasurement  by us e of  thereferen ce  light  R,  t he distanc e  determin ed by  use of  t he f ore goingdist a n ce me asur in g l ight L ca n be co rr e cte d. S uch a  d evic e is disc l osed inJap a nese Pu bl ish e d  Unexa m in e d  Patent Ap pli catio n No. 2004-2 6 4116 . 
I n  such  a dis tancemeasuri n g d ev ice, si nce t he distan ce has be e n c al cula ted afte rcons ec uti ve ly sampling the  interme diate fr e q uencysig n al I F  for m or e than a few  thou sa n ds of a l arg e numbe r 
β from_the measured_initial phase β.
In this_distance measuring_device,_prior to_a_distance measurement, the_distance measuring device_is actuated to carry_out preliminary sampling_to_sample a few cycles of the intermediate frequency signal IF preliminarily. This is carried_out_to detect_sampling_positions_at the maximum level Amax_and the minimum level Amin_within one-cycle_range of the intermediate frequency signal IF and_to_thereby simplify the_subsequent detection of the amplitude Ai. In addition, in_order to obtain frequency distribution of_the amplitude Ai,_the_amplitude_range is divided into_a plurality of grades, and a_storage area to hold frequencies of_the respective grades is prepared in the_memory 46.
Then, a distance measurement is_started, and every time one_cycle of_the intermediate frequency signal IF_has been detected,_the synthetic_data S (FIG._3) for which sampling data at_the same phase_position has been added is stored_in_the memory 46,_and_based_on ½_of a difference_in_levels between_the_sampling positions that have indicated the_maximum_level Amax and the minimum level Amin_determined from the result_of_the preliminary sampling prior_to the distance measurement, a_grade of the amplitude Ai of_the intermediate_frequency signal_IF is determined, 1 is added to the frequency of that_grade, and frequency distribution of the_amplitude Ai is also_stored in_the_memory 46. After_completion_of the_sampling, the initial phase β is determined_by use_of the synthetic sine wave S′_of the intermediate frequency_signal_IF, and by use of the_frequency distribution of the amplitude Ai,_the weighted average Σ{Ai·Δφi(Ai)}/ΣAi obtained_by_weighting_the correction amount Δφi(Ai) with_the amplitude Ai of the intermediate_frequency signal IF,_namely, the correction amount Δβ is calculated._Then,_the correction amount Δβ is subtracted_from_the initial phase β to calculate_a_distance_to the target 22.
As a_matter of course, in this distance_measuring device as well, the distance measuring light L_can be switched_to a reference light R_that_leads_to the light receiving element 28 through an internal light_path including_a diaphragm 27a._By carrying out a distance measurement by use of the_reference light R, the distance determined by_use of the foregoing distance measuring light L can be corrected._Such a device is disclosed in Japanese Published_Unexamined Patent Application No. 2004-264116.
In such a_distance measuring device, since_the_distance has been calculated after consecutively sampling_the_intermediate_frequency_signal IF for_more than a_few thousands of_a large_number