使用ADS131M04进行对基本标准的1khz信号进行采集，采样速率是16ksps，配置的OSR为256，主频CLK用的8Mhz的外部晶振，采样20个周期信号数据（320个采样点）进行16点的DFT运算，发现在幅值基本稳定的情况下，一直产生相位偏移。其中黄色线为相位 蓝色为幅度
软件中按照DRDY的触发中断进行对adc通道数据的读取，在读取到对应通道的可读状态位置1后对所有通道的数据进行读取，测量DRDY的触发频率基本也在16.6khz左右。上电后也按照间隔2us对SYNC引脚进行时钟同步，请问是什么原因？
以下是抓不到的20个周期的样本值。
-16.836262 -39.346361 -55.699396 -63.251352 -60.869980 -48.868275 -29.139090 -4.910231 19.995546 41.620445 56.502771 62.277603 57.967472 44.276905 23.458099 -1.196337 -25.788975 -46.334553 -59.653902 -63.552475 -57.384682 -42.200518 -20.387363 4.574919 28.680611 48.147869 59.810829 61.841583 53.857613 37.146664 14.470339 -10.634995 -34.145164 -52.353001 -62.281179 -62.398911 -52.673292 -34.628820 -11.180592 13.925171 36.728954 53.573656 61.751747 59.969759 48.501492 29.169273 5.128813 -19.845629 -41.787529 -57.180977 -63.524294 -59.850454 -46.763563 -26.303387 -1.746225 22.970867 43.919849 57.768345 62.292337 56.749964 42.035294 20.498943 -4.383230 -28.664875 -48.493624 -60.684729 -63.290977 -55.942583 -39.806986 -17.333794 7.706451 31.439924 50.070047 60.585022 61.334896 52.190495 34.592772 11.382294 -13.756227 -36.811781 -54.106379 -62.849092 -61.727571 -50.835371 -31.929159 -8.058071 16.968584 39.204168 55.123615 62.102079 59.048367 46.448278 26.338005 1.952076 -22.849274 -44.115973 -58.487463 -63.605690 -58.689451 -44.551277 -23.380852 1.385593 25.841761 46.104527 58.859396 62.109089 55.333471 39.640188 17.505312 -7.514763 -31.447363 -50.460720 -61.558771 -62.951660 -54.434681 -37.277842 -14.276075 10.838127 34.151459 51.908112 61.250067 60.716629 50.406647 31.932449 8.237743 -16.844559 -39.359665 -55.687380 -63.254786 -60.839939 -48.868275 -29.166269 -4.926395 19.989967 41.620445 56.487751 62.232256 57.954454 44.306231 23.466825 -1.195192 -25.757360 -46.350288 -59.652328 -63.564491 -57.412863 -42.215681 -20.404530 4.576921 28.710365 48.149014 59.797668 61.800814 53.831148 37.144375 14.453602 -10.646009 -34.162331 -52.353287 -62.299061 -62.408495 -52.696180 -34.647131 -11.191607 13.919020 36.694908 53.556061 61.723995 59.955454 48.497057 29.199886 5.121374 -19.861794 -41.793823 -57.195854 -63.558626 -59.872198 -46.750116 -26.290512 -1.764679 22.944117 43.879652 57.736015 62.250853 56.719494 42.019129 20.510960 -4.351902 -28.688622 -48.529387 -60.729647 -63.363218 -55.996799 -39.834452 -17.410040 7.670689 31.436777 50.062323 60.584021 61.335897 52.208519 34.592199 11.361694 -13.768673 -36.832809 -54.112244 -62.864971 -61.724424 -50.851536 -31.966782 -8.062506 16.975307 39.186716 55.077553 62.085056 59.055948 46.466732 26.382637 2.019882 -22.820091 -44.129848 -58.463573 -63.577795 -58.709478 -44.537544 -23.355818 1.441240 25.857353 46.077061 58.859396 62.140274 55.381393 39.664221 17.516470 -7.488012 -31.420183 -50.457716 -61.576080 -62.943506 -54.396486 -37.276268 -14.280653 10.837555 34.165764 51.908970 61.249352 60.756397 50.426388 31.932878 8.283091 -16.782475 -39.327765 -55.690813 -63.246632 -60.859108 -48.875856 -29.150105 -4.907942 19.974947 41.605139 56.482315 62.226534 57.974768 44.319534 23.461246 -1.189613 -25.759220 -46.358585 -59.647608 -63.528299 -57.397413 -42.241430 -20.391655 4.605532 28.699780 48.141861 59.805393 61.805534 53.828001 37.159967 14.491081 -10.623837 -34.157324 -52.331114 -62.284756 -62.398052 -52.664137 -34.630823 -11.200762 13.903284 36.712217 53.587818 61.735439 59.961176 48.523951 29.178429 5.104923 -19.863653 -41.768503 -57.158947 -63.517857 -59.855318 -46.757984 -26.320410 -1.751089 22.931957 43.866205 57.726288 62.250566 56.713486 42.026138 20.526695 -4.356909 -28.641129 -48.461866 -60.694027 -63.331175 -55.968761 -39.804983 -17.390156
