hereinafter , embodiments according to the present invention will be fully explained by referring to the attached drawings . herein , fig1 is a block diagram of a disk recording apparatus according to the present invention . in this fig1 a reference numeral 101 is a means for detecting a pre pit formed on a land track of a disk , 102 a means for detecting an even sync pattern from the pre pit detected , and 103 a means for detecting an odd sync pattern from the pre pit detected . the even sync pattern detection means 102 detects the pattern “ 111 ”, and the odd sync pattern detection means 103 detects the pattern “ 110 ”, respectively . a reference numeral 104 depicts an detection cycle counter , turning one ( 1 ) round by 16 × 13 wobbles , and it is synchronized with a timing , at which the respective patterns should be generated , when the sync signals are detected by the even sync pattern detection means 102 and the odd sync pattern detection means 103 , respectively . a reference numeral 105 depicts a detection window , which is produced by the detection cycle counter 104 and is opened at a position where the odd sync pattern should be generated . a reference numeral 106 depicts another detection window , which is produced by the detection cycle counter 104 and is opened at a position where the even sync pattern should be generated . a reference numeral 107 depicts an even / odd un - detect signal generation means , and it generates an even / odd un - detect signal when the detection cycle counter 104 counts up for a predetermined period , but not being synchronized with upon detection of the even / odd sync pattern . a un - detect number counter 108 counts the number of times when the even / odd un - detect signals are generated , continuously , but without detecting the even / odd sync pattern . a reference numeral 109 is a sync un - detect number count setting value , and it produces a sync lock flag reset signal when the even / odd sync pattern un - detect continues and reaches to the number of times , which is set in advance . a sync lock flag 110 is reset by any one of the sync lock flag reset signal from 109 , the even sync pattern detection signal from 105 , which is gated through the odd window , and the odd sync pattern detection signal from 106 , which is gated through the even window . a gate circuit 116 is opened in a case where the sync lock flag 110 is reset into the unlock condition . when the gate circuit 116 is opened , the sync lock flag 110 is set into the lock condition , by either one of the even sync pattern detection signal , which is detected by the even sync pattern detection means , or the odd sync pattern detection signal , which is detected by the odd sync pattern detection means . in this manner , the sync lock flag 110 turns into the unlock condition , in any cases where the sync pattern cannot be detected , continuously , for a predetermined time period , when the odd sync pattern is detected at the position where the even sync pattern should be generated , and when the even sync pattern is detected at the position where the odd sync pattern should be generated , and also it turns into the lock condition when the sync pattern is detected under the unlock condition . if the sync lock flag continues to be under the lock condition for a time period determined by a sync lock flag check region production means 111 , a recording cycle counter 112 for producing a recording timing is synchronized with the detection cycle counter . an encoder 113 conducts the encode processing in accordance with the dvd format , at the timing produced by the recording cycle counter . after being waveform shaped in a laser diode driver 114 , the encoded signal drives a laser diode 115 . as was mentioned in the above , according to the present embodiment , even if the last digit is lost from the even sync pattern , i . e ., “ 111 ”, then it comes to be the odd sync pattern , i . e ., “ 110 ”, since it is protected by means of the sync flag ; therefore the synchronization can be carried out on the recording timing , with stability . next , explanation will be made on examples of the land pre pit signals , to be used in the present invention , by referring to fig2 , 4 and 5 . all of those fig2 , 4 and 5 are in accordance with the standard of the land pre pit of the dvd - r / rw shown in fig6 and 7 . in fig2 the “ even sync pattern ” lies at the position of “ even ”, i . e ., at the head of 201 , and at the position of “ even ” following thereto lies “ 0 ( binary )” data . on 202 - 206 , the data “ 0000000000 ( binary )” lies at the position of “ even ”. on 207 , “ 1 ( binary )” lies at the first “ even ” position , and at the “ even ” position following thereto lies “ even sync pattern ”. in the similar manner , on 208 - 210 , “ 000100 ( binary )” lies at the “ even ” position . comparing this to fig6 it can be seen that a relative address “ 0000 ” lies after the “ sync pattern ” of 201 , and that a relative address “ 0001 ” after the sync pattern of 207 . in fig2 is shown a case where all the land pre pits lie at the positions of “ even ”, however according to the dvd standard , it is determined to use the “ odd ” position , so that the land pre pits are not adjacent to each other on the neighboring tracks . an example , where data is also recorded at the “ odd ” position , is shown in fig3 . comparing this to fig6 and 7 , it can be seen that the relative address “ 0000 ” and the data “ 00000001 ” lie after the “ sync pattern ” of 301 , and the relative address “ 0001 ” lies after the “ sync pattern ” of 307 . in the example shown in fig3 although the “ odd ” sync pattern is used on 307 , the data at the “ odd ” position on 302 , 304 and 305 are same to the data shown in fig2 . next , an example is shown in fig4 where the sync pattern is erroneously recognized , due to such as a result of filtering process , etc . in the example shown in fig4 the last pulse is lost on the even sync pattern “ 111 ” at the position 407 where the even sync patter is recorded , thereby changing into the odd sync pattern , i . e ., “ 110 ”. accordingly , if recognizing the position where the odd sync pattern is detected to be the position of the “ odd ”, there occurs shifting in the position recognition . in the embodiment shown in fig1 the detection cycle counter is synchronized with the even sync pattern of 401 , and then the windows are produced at the position where the even sync patter should be generated and the position where the odd sync pattern should be generated . in fig4 since the odd sync pattern is detected within the window at the position where the even sync patter should be generated , then the even sync pattern is in the unlock condition . for this reason , the recording cycle counter is inhibited from being synchronized with the detection cycle counter , and therefore the recording is protected from causing the position shifting therein . next , an example is shown in fig5 where a pseudo sync pattern is produced , due to mixture of noises , etc . in the example shown in fig5 “ 1 ” rises up at the last bit of the odd sync pattern “ 110 ”, i . e ., at the position 507 where the odd sync patter is recorded , due to noises , then it is erroneously recognized to be the even sync pattern “ 111 ”. accordingly , if recognizing the position where the even sync pattern is detected to be the position of the “ even ”, there occurs shifting in the position recognition . in the embodiment shown in fig1 since the even sync pattern is detected within the window at the position where the odd sync pattern should be generated , the sync lock flag is in the unlock condition . for this reason , the recording cycle counter is inhibited from being synchronized with the detection cycle counter , and therefore the recording can be protected from being shifted in the position thereof . next , operation of the detection sync counter will be explained by referring to fig8 . the horizontal axis in fig8 indicates a reproduction position while the vertical axis a value of the counter . being synchronized upon the even sync pattern detection at the left - hand side end in the same figure , the counter value is comes down to zero ( 0 ). then , it counts up the count value by every wobble . after one ( 1 ) sector , i . e ., at 208 th wobble (= 8 wobbles × 2 × 13 ), it is the position where the next even sync pattern should be generated . accordingly , the counter counts up to 207 , and it detects the even sync pattern at the position of 208 th wobble , thereby turning back to zero ( 0 ), thereafter conducting the count up , again . further , the similar processing is carried out when detecting the next odd sync pattern upon the basis of the odd sync pattern detection . [ 0041 ] fig9 also shows the operation of the detection counter , in a similar manner . the count value comes down to zero ( 0 ) at the left - hand side end when detecting the even sync pattern , and thereafter it counts up the count value for every wobble . since the next sync pattern lies at the “ odd ” position in fig9 th wobble (= 1 sector + 8 wobbles ) is the position where the next odd sync pattern should be generated . accordingly , after counting the count value up to 215 , it is preset to eight ( 8 ). however , when detecting the next even sync pattern upon the basis of the odd sync pattern detection , since 200 th wobble (= 1 sector − 8 wobbles ) from the odd sync pattern is the position where the next even sync pattern should be generated , therefore the count value is preset to 0 after counting up to 199 . next , explanation will be given on synchronization in the recording cycle counter , by referring to fig1 . this fig1 shows the detection condition for each of the sync signal of “ even ” or “ odd ” at a unit of sector , and behavior of the sync lock flag for it , as well as , the synchronization operation of the recording cycle counter . in fig1 , “ x ” indicates the condition where the odd sync pattern is detected within the even sync pattern detection window , or the condition where the even sync pattern is detected within the odd sync pattern detection window . a mark “ δ ” indicates a case where no new sync pattern cannot be detected after passing 208 or 215 wobble cycles . a mark “ o ” indicates the condition where the even sync pattern is detected within the even sync pattern detection window , or the condition where the odd sync pattern is detected within the odd sync pattern detection window . the “ sector no .” indicates the relative address , which was shown in fig6 from bit 1 to bit 4 . in 1001 , the sector 15 at the end of the left - hand side is in the “ x ” condition , and the sync lock flag is in the unlock condition . it comes into the “ o ” condition at the sector 1 , and then the sync lock flag turns back into the lock condition . hereinafter , the detection condition continues to be “ o ” from the sector 0 to the sector 15 , and the sync lock flag continues to be the lock condition . when continuing the lock condition during this time period , the synchronization is carried out on the recording cycle counter . next , an example of the time period is shown , which is determined by the sync lock flag check region producing means 111 shown in fig1 . in 1002 , it is in the “ x ” condition at the sector of the left - hand side end , and then the sync lock flag is in the unlock condition . also , it is in the “ o ” condition at the sector 1 , and then the sync lock flag turns back to the lock condition . the “ δ ” condition continues eight ( 8 ) times from the sector 4 , and at the sector 11 , the sync lock flag turns into the unlock condition . herein is shown a case where the setting number of times is eight ( 8 ), in the operation of producing the sync lock flag reset signal when the even / odd sync pattern un - detect shown in fig1 reaches to a number of times that is set in advance . in this case , since the lock condition does not continue for the time period from the sector 0 to the sector 15 , therefore no synchronization is carried out on the recording cycle counter . in the above , the detailed operation was explained on the recording cycle counter . however , although it is indicated that the synchronization may be conducted by any number of times , if the lock condition continues for the time period between the sector 0 to the sector 15 , in the present example , but it is also possible that the synchronization is conducted only one ( 1 ) time , i . e ., at the first time among those when the conditions are satisfied , during the time period , starting from beginning read - out of the land pre pits after moving a pick until the recording . limiting the number of times of synchronization to only one ( 1 ) time enables to reduce the possibility of shifting due to the erroneous sync patter , much more . next , explanation will be given on other embodiment according to the present invention . fig1 is a block diagram of the disc recording apparatus according to the present invention . in fig1 , the structures are same to those shown in fig1 but except for 1101 and 1102 . the reference numeral 1101 indicates an odd sync pattern counter , and it counts up the number of the odd sync patterns within the region , which is determined by the sync lock flag check region production means 111 , so as to resets the sync lock flag 1102 when it exceeds a predetermined number , thereby bringing it into the unlock condition . other operations thereof are same to those of the disc recording apparatus shown in fig1 . the present embodiment utilizes the fact that , inherently , the odd sync pattern is used for the purpose of shifting the position thereof if the even sync patterns are adjacent with each other on the neighboring tracks , and therefore it will never exceeds a certain ratio . according to the present embodiment , it is possible to enhance the protection from generating the position shifting when recording . next , explanation will be given on further other embodiment according to the present invention . fig1 is a block diagram of the disc recording apparatus according to the present invention . in fig1 , the structures are same to those shown in fig1 , but except for 1201 , 1202 and 1203 . the reference numeral 1201 indicates a sync detection window ; thus , a window to be opened at the position where the even sync pattern or the odd sync pattern should be generated . the detection cycle counter 1202 may be synchronized with , also via the sync pattern not passing through the sync detection window 1201 , in the case where the sync lock flag 1102 is in the unlock condition , however in the case where the sync lock flag is in the lock condition , the synchronization is carried out on the detection cycle counter 1202 only when the sync pattern detection is conducted within the sync detection window 1201 . however , this sync detection window 1201 is produced by means of detection cycle counter 1202 . also , an un - detect number counter 1203 may be reset by the sync pattern that does not passing through the sync detection window 1201 , in the case where the sync lock flag 1102 is in the unlock condition , however in the case where the sync lock flag is in the lock condition , it is reset only in the case where the sync pattern detection is conducted within the sync detection window 1201 . other operations are similar to those of the disc recording apparatus shown in fig1 . according to the present embodiment , since the detection cycle counter 1202 does not conduct the synchronization on the pseudo sync pattern during when conducting the sync lock , even in the case where the pseudo sync patterns are generated due to noises at the land pre pits indicating the data bits , therefore no such the position shift occurs in the recording cycle counter , thereby achieving the recording at the correct position . next , explanation will be given on further other embodiment according to the present invention . fig1 is a block diagram of the disc recording apparatus according to the present invention . in fig1 , the structures are same to those shown in fig1 , but except for 1301 , 1302 and 1303 . the reference numeral 1301 indicates a reverse signal of the sync detection window 1201 , and it opens the window at the position where , inherently , the sync signal should be detected . the reverse window 1301 is produced by means of a detection cycle counter 1302 . with the sync pattern , passing through the reverse window 1301 to be detected , a sync lock flag 1303 is reset , and it is in the unlock condition . accordingly , the recording cycle counter is not synchronized with , even if detecting the sync pattern passing through the reverse window , therefore the synchronization will not occur , erroneously . as was fully explained in the above , according to the present invention , it is possible to protect the recording position from being shifted in the position thereof , if the even sync pattern is erroneously detected to be the odd sync pattern , or if the odd sync pattern is erroneously detected to be the even sync pattern . the present invention may be embodied in other specific forms without departing from the spirit or essential feature or characteristics thereof . the present embodiment ( s ) is / are therefore to be considered in all respects as illustrative and not restrictive , the scope of the invention being indicated by the appended claims rather than by the forgoing description and range of equivalency of the claims are therefore to be embraces therein .