the present invention is related to systems and methods for accessing a magnetic storage medium , and more particularly to systems and methods for detecting data patterns from a magnetic storage medium . various embodiments of the present invention provide for burst demodulation common to processing information from a magnetic storage medium that is synchronized to a reliable 4t boundary , rather than a less reliable 1t boundary . in some embodiments of the present invention , a sam is found , but it does not necessarily control the synchronization of subsequent processing of burst demodulation . rather , the sam found location or time is double checked against a reliable 4t boundary indicator to assure that the sam found is properly located . where sam found is identified coincident with a 4t boundary , the processing of burst demodulation proceeds synchronous to the sam found . alternatively , where the sam found is not coincident with a 4t boundary , burst demodulation processing is synchronized to a subsequent or preceding 4t boundary . as one of various advantages , the aforementioned alignment reduces or eliminates the possibility that the head location of a hard disk drive is confused between being offtrack or ontrack . in some cases , the 4t alignment utilizes a bit quad sync circuit that is already implemented in a read channel for other purposes . in such a case , modifications are made to allow use of an existing circuit to perform a novel synchronization approach in accordance with different embodiments of the present invention . based on the disclosure provided herein , one of ordinary skill in the art will recognize other advantages that may be achieved in accordance with embodiments of the present invention . turning to fig4 , a flow diagram 500 depicts a method in accordance with some embodiments of the present invention for synchronizing to an asynchronous signal . following flow diagram 500 , filtered and / or formatted data is continuously received as a stream of data ( block 505 ). this may include accessing information from a track of a magnetic storage medium . such a magnetic storage medium may be a platter incorporated in a hard disk drive . the data may include user information in addition to information from servo data sectors that are intermixed between the user information . such servo data sectors may include , but are not limited to , a preamble pattern that is followed by a servo address mark ( sam ). in addition , the sam may be followed by encoded gray data and one or more burst demodulation fields . the received data is monitored to determine whether a known preamble pattern from a servo data sector has been received ( block 507 ). various preamble patterns may be utilized in accordance with different embodiments of the present invention . where the preamble pattern has not yet been detected ( block 507 ), the received data stream is continually monitored for the preamble . when the preamble pattern is identified ( block 507 ), a digital interpolation is performed to identify the peaks of the received data as sampled ( block 525 ). such digital interpolation may be better understood through reference to an exemplary waveform 600 of fig5 that represents received data . it should be noted that in a search mode of operation a continuous detection process may be performed while looking to identify the preamble as previously discussed . in addition , the data is monitored to determined 4t boundaries as is known in the art ( blocks 510 , 515 , 520 ). however , in a normal mode of operation , the location of the preamble is known as it ( or another preamble ) was previously detected . in such a case , block 507 , block 510 , block 515 and block 520 would be adequately replaced by a block that simply stated “ receive 4t boundary identification ” as the 4t boundary would be known . this 4t boundary could then be used in identifying an appropriate start point in accordance with different embodiments of the present invention . in the end , once the sam is found ( block 535 ) and the 4t boundary is known ( block 520 ), the burst demodulation is synchronized to either a 4t boundary that occurs concurrent with a 1t boundary at which the sam was found , or at either a 4t boundary preceding or succeeding the boundary at which the sam was found . turning to fig5 , waveform 600 is sampled a number of times over a period extending from one peak 605 to a subsequent peak 610 . peak 605 and peak 610 are referred to as “ 4t boundaries ”. in addition , waveform 600 is divided into four “ 1t sections ” in this case , a 1t boundary 615 exists coincident to 4t boundary 605 , and another 1t boundary 635 exists coincident with 4t boundary 610 . other 1t boundaries 620 , 625 , 630 are set at the ¼ , ½ and ¾ locations of waveform 600 . in one particular embodiment of the present invention , the sampling rate of waveform 600 is set at 1t , and interpolation points ( identified as t / 8s ) are created for each sample period . the samples may be used in the above mentioned digital interpolation process of block 525 to identify the various contours and transitions of wave form 600 . this digital interpolation provides points on waveform 600 that may be used to determine the best phase of waveform 600 ( in this case the best 1t boundary ) at which to identify the sam ( block 530 ). again , using waveform 600 as a particular example , the best phase is determined using a t / 8 interpolation resolution . determination of the best phase in part governs synchronization with a succeeding burst demodulation field . the sampling process continues until the sam is found ( block 530 ). with the sam found ( block 530 ), identification of the succeeding gray code and burst demodulation may be accomplished based on a “ location ” of the identified sam ( block 535 ). the location may be , for example , a time marker from which a counter may be referenced ( i . e ., a counter may be reset when the sam is found ). based on the disclosure provided herein , one of ordinary skill in the art may recognize a number of approaches for identifying the location of a sam found such that the identification may be used to predict a point at which a future event is predicted . in some cases , the aforementioned best phase may be used to count the expected location of the succeeding burst demodulation . in such a case , the best phase would determined through a comparison with a threshold of 3t / 8 to determine if a sampling of the succeeding burst demodulation is to be synchronized to the cycle immediately succeeding the sam , or to wait a cycle . specifically , where the best phase is less than or equal to the 3t / 8 location , then a counter operating to synchronize the start of burst demodulation starts from the current cycle . otherwise , the counter starts counting from the next cycle . said another way , an attempt is made to identify a 1t boundary from which the demodulation counting is started . in some cases , however , relying on a 1t boundary problematic where a channel is either not optimized or where there is substantial noise or a low signal to noise ratio in the channel . in particular , it is possible that any noise in the channel may corrupt a timing mark based on a 1t boundary . consequently , synchronization to the burst demodulation may be off by 1t . such an error may make the difference between sampling at a minimum instead of a maximum . this can be a problematic in a hard disk drive scenario that could in the worst case result in user data being erroneously erased . in addition , when the preamble pattern is identified ( block 507 ), a 4t boundary identification is preformed ( block 510 ). as previously stated , this detection may have already occurred in which case the 4t boundary is merely provided rather than being re - established . using exemplary waveform 600 , identification of a 4t boundary includes identifying peak 605 and peak 610 . in one particular embodiment of the present invention , a bit quad sync circuit is used to identify the 4t boundary . in such a case , the analog to digital converted value corresponding to a 2t preamble may be , for example : 0 , 20 , 0 , − 20 , 0 , 20 , 0 , − 20 . the aforementioned bit quad sync circuit may filter these samples with [ 1 1 − 1 − 1 1 1 − 1 − 1 ] to yield a filtered output of : 80 , 80 , − 80 , − 80 , 80 , 80 , − 80 , − 80 . this filtered output may then be detected with a threshold comparator implementing a comparison with zero such that the 2t preamble pattern ‘ 110011001100 ’ results . the bit quad sync circuit then compares the detected pattern with ‘ 11001100 ’, ‘ 10011001 ’, ‘ 00110011 ’ or ‘ 01100110 ’. the results of the comparison identifies a reliable 4t boundary ( i . e ., peak 605 or peak 610 ) for the 2t preamble phase . with the 4t boundary found ( block 515 ), identification of the succeeding gray code and burst demodulation may be accomplished based on a “ location ” of the identified 4t boundary ( block 520 ). again , the location may be , for example , a time marker from which a counter may be referenced ( i . e ., a counter may be reset when the 4t boundary is found ). based on the disclosure provided herein , one of ordinary skill in the art may recognize a number of approaches for identifying the location of a 4t boundary such that the identification may be used to predict a point at which a future event is predicted . both the 4t boundary location ( block 520 ) and the sam found location ( block 535 ) are used in combination to determine when to expect the subsequent burst demodulation field . in particular , the burst demodulation is synchronized to the identified 4t boundary . in some cases , the sam found occurs at a 4t boundary . in such cases , the sam found provides the location from which processing of the burst demodulation is synchronized . as mentioned above , however , the sam found may possibly be misidentified by 1t or more . in such cases , processing of the burst demodulation is delayed until the next 4t boundary is identified . thus , one advantage of some embodiments of the present invention is the avoidance of the detrimental effects of misalignment of the sam found and 4t boundary . with the burst demodulation synchronized to a 4t boundary either coincident with a sam found or occurring after a sam found , the burst demodulation may be performed ( block 550 ). turning to fig5 , exemplary waveform 600 may be used to provide a particular example of processing in accordance with various embodiments of the present invention . in the example , assume that sam found occurs somewhere between peak 605 and peak 610 ( i . e ., exemplary 4t boundaries ). in such a case , burst demodulation would be synchronized to peak 610 . alternatively , assume that sam found occurs coincident with peak 605 . in such a case , burst demodulation would be synchronized to peak 605 . it should be noted that the 4t boundary may be established at other locations on exemplary waveform 600 depending upon particular circumstances . for example , a 4t boundary may be established at minimum peak 625 . based on the disclosure provided herein , one of ordinary skill in the art will recognize 4t boundaries that may be used in relation to a sam found signal to synchronize processing of burst demodulation . turning to fig6 , a readback channel 400 in accordance with various embodiments of the present invention is depicted . readback channel 400 may be implemented to , for example , access data from a magnetic storage medium ( not shown ). in the situation where readback channel is implemented in relation to a magnetic storage medium , read channel 400 may receive read data 405 from the magnetic storage medium . read data 405 may include a servo waveform corresponding to an encoded servo pattern . read data 405 is provided to an analog filter circuit 410 that is operable to receive read data 405 and filter it to a desired level and / or frequency . in one particular embodiment of the present invention , analog filter circuit 410 includes a combination of a continuous time filter ( ctf ) and a finite impulse response ( fir ) filter . based on the disclosure provided herein , one of ordinary skill in the art will recognize a variety of filter types and combinations of filter types that may be utilized to equalize or otherwise massage read data 405 into a desired signal level and / or frequency . an analog output 412 of analog filter circuit 410 is provided to an analog to digital converter 415 where it is converted from the analog signal domain to a digital signal domain . analog to digital converter 415 may be any analog to digital conversion circuit or process known in the art . the amount of resolution offered by analog to digital converter 415 may be selected based on the particular requirements of a given embodiment of the present invention . in one particular embodiment of the present invention , analog to digital converter 415 is a six bit analog to digital converter . a digital output 417 from analog to digital converter 415 is provided to both a sam identification circuit 401 and to a bit quad sync (“ bqs ”) circuit 430 . sam identification circuit 401 is operable to detect a servo address mark within a servo data sector of a magnetic storage medium . sam identification circuit 401 includes a digital filter circuit 420 , a digital interpolation circuit 425 , a best phase selection circuit 435 and a sam detector circuit 440 . digital filter circuit 420 filters digital output 417 as is known in the art . in one particular embodiment of the present invention , digital filter circuit 420 is a five tap constrained digital finite impulse response filter as is known in the art . based upon the disclosure provided herein , one of ordinary skill in the art will recognize a variety of digital filters that may be implemented in accordance with different embodiments of the present invention . the filtered digital signal is interpolated to identify discrete signal locations of a waveform using digital interpolation circuit 425 . using the interpolated signals , a best phase for sampling the waveform is determined by a best phase selection circuit 435 . as previously discussed , best phase selection circuit 435 utilizes a number of interpolated samples to determine the best phase for detecting information in a waveform . in some cases , eight samples are used to predict the best phase . in such a case , the best phase may be determined through a comparison with a threshold of 3t / 8 to determine if a sampling of the succeeding burst demodulation is to be synchronized to the cycle immediately succeeding the sam , or to wait a cycle . specifically , where the best phase is less than or equal to the 3t / 8 location , then a counter operating to synchronize the start of burst demodulation starts from the current cycle . otherwise , the counter starts counting from the next cycle . said another way , an attempt is made to identify a 1t boundary from which the demodulation counting is started . in some cases , however , relying on a 1t boundary problematic where a channel is either not optimized or where there is substantial noise or a low signal to noise ratio in the channel . in particular , it is possible that any noise in the channel may corrupt a timing mark based on a 1t boundary . consequently , synchronization to the burst demodulation may be off by 1t . such an error may make the difference between sampling at a minimum instead of a maximum . this can be a problematic in a hard disk drive scenario that could in the worst case result in user data being erroneously erased . using the identified best phase , the location of a sam in the servo data is identified using sam detector circuit 440 . sam detector circuit 440 may be , for example , a comparator that continually compares received values against a desired sam . sam detector circuit 440 provides a sam found output to a samfound alignment circuit 445 . bqs circuit 430 operates to identify 4t boundaries of a received waveform . in one particular embodiment of the present invention , read data 405 may include the following exemplary 2t preamble : 0 , 20 , 0 , − 20 , 0 , 20 , 0 , − 20 . analog filter 410 may filter using [ 1 1 − 1 − 1 1 1 − 1 − 1 ] to yield : 80 , 80 , − 80 , − 80 , 80 , 80 , − 80 , − 80 . analog to digital converter circuit 415 threshold compares the received signal with zero to yield the 2t preamble pattern , ‘ 110011001100 ’. bqs circuit 430 compares the aforementioned 2t preamble pattern with ‘ 11001100 ’, ‘ 10011001 ’, ‘ 00110011 ’ or ‘ 01100110 ’. the results of the comparison identifies a reliable 4t boundary ( i . e ., peak 605 or peak 610 ) for the 2t preamble phase . bqs circuit 430 provides a 4t boundary found signal to samfound alignment circuit 445 . samfound alignment circuit 445 combines the indications of sam found and 4t boundary found to synchronize subsequent burst demodulation by a burst demodulation circuit 450 . in particular , burst demodulation circuit 450 is signaled to begin burst demodulation at an identified 4t boundary . thus , where the samfound signal from sam detector circuit 440 is received coincident with a 4t boundary identified by bqs circuit 430 , samfound alignment circuit 445 signals burst demodulation circuit 450 to begin processing immediately . alternatively , where the samfound signal from sam detector circuit 440 is received at a time that is misaligned from a 4t boundary identified by bqs circuit 430 , samfound alignment circuit 445 signals burst demodulation circuit 450 to begin processing on the next 4t boundary . burst demodulation circuit 450 may be any burst demodulation circuit known in the art . burst demodulation circuit 450 receives the filtered and converted read data 405 , and provide demodulated data 460 . as just one of many advantages of some embodiments of the present invention , the possibility of confusing an offtrack head location for an ontrack head location will be reduced for servo demodulation . at least in part , this is because demodulation may be done based on a reliable 4t boundary rather than a less reliable 1t boundary . in many hard disk drive application , a bqs circuit is already in place in the channel , and therefore the cost of implementing systems in accordance with the present invention may be relatively small . in conclusion , the invention provides novel systems , devices , methods and arrangements for improving data synchronization . while detailed descriptions of one or more embodiments of the invention have been given above , various alternatives , modifications , and equivalents will be apparent to those skilled in the art without varying from the spirit of the invention . therefore , the above description should not be taken as limiting the scope of the invention , which is defined by the appended claims .