[MATLAB信号处理] 请问如何获得一组变化剧烈曲线的拟合函数

[victoryhx]

我现在有一组x-y的数据，y的变化相对于x而言变化非常剧烈，我想获得这条曲线的函数表达式。
我尝试过用cftool里面的各种预设的拟合方式，都不能获得比较好的拟合，请问我该怎么解决呢？
接触matlab不太久，求各路大神指点。
附数据如下：
0.000 3.391
0.010 5.499
0.020 4.399
0.029 1.008
0.039 -0.550
0.049 -0.916
0.059 2.474
0.068 3.849
0.078 1.925
0.088 -0.825
0.098 -1.558
0.107 -0.275
0.117 -0.183
0.127 -0.092
0.137 -0.642
0.146 0.000
0.156 2.749
0.166 3.391
0.176 1.650
0.186 0.000
0.195 -0.642
0.205 0.367
0.215 2.383
0.225 1.283
0.234 -1.375
0.244 -0.550
0.254 1.191
0.264 1.283
0.273 -0.733
0.283 -1.650
0.293 -1.650
0.303 -1.833
0.312 -2.016
0.322 0.092
0.332 2.291
0.342 -0.458
0.352 -1.833
0.361 -1.558
0.371 -0.550
0.381 -0.825
0.391 0.550
0.400 0.916
0.410 1.466
0.420 2.841
0.430 4.307
0.439 2.933
0.449 0.000
0.459 0.000
0.469 -0.275
0.479 0.733
0.488 0.092
0.498 -2.200
0.508 -1.558
0.518 0.825
0.527 0.092
0.537 -1.466
0.547 -1.191
0.557 -1.191
0.566 -1.925
0.576 -3.116
0.586 -2.749
0.596 -1.191
0.605 -2.108
0.615 -2.658
0.625 -0.183
0.635 -0.550
0.645 0.000
0.654 0.458
0.664 -0.642
0.674 -1.283
0.684 -1.925
0.693 -1.466
0.703 -0.275
0.713 -0.275
0.723 0.275
0.732 1.925
0.742 2.658
0.752 2.383
0.762 0.733
0.771 -1.100
0.781 -0.275
0.791 -0.183
0.801 -0.733
0.811 -1.741
0.820 0.275
0.830 2.016
0.840 0.733
0.850 -0.642
0.859 -2.108
0.869 -2.291
0.879 -0.183
0.889 0.550
0.898 2.933
0.908 1.650
0.918 -0.916
0.928 -1.741
0.937 1.008
0.947 1.191
0.957 -0.275
0.967 -0.183
0.977 -0.367
0.986 -1.100
0.996 -0.916
1.006 -1.191
1.016 0.367
1.025 -0.092
1.035 0.275
1.045 0.367
1.055 0.000
1.064 0.092
1.074 0.733
1.084 1.375
1.094 1.100
1.104 -0.642
1.113 -1.558
1.123 -1.100
1.133 -0.458
1.143 -0.458
1.152 0.733
1.162 1.283
1.172 0.733
1.182 -0.458
1.191 -0.825
1.201 -1.650
1.211 -0.550
1.221 0.092
1.230 -1.558
1.240 -2.383
1.250 -2.291
1.260 -1.466
1.270 -0.733
1.279 0.825
1.289 0.550
1.299 0.916
1.309 0.092
1.318 -1.466
1.328 -1.375
1.338 -0.550
1.348 -0.367
1.357 1.008
1.367 1.925
1.377 0.367
1.387 -1.100
1.396 0.825
1.406 2.933
1.416 0.550
1.426 -2.383
1.436 -1.833
1.445 0.825
1.455 0.550
1.465 -0.550
1.475 -1.466
1.484 -2.291
1.494 -1.008
1.504 -0.825
1.514 0.367
1.523 -0.183
1.533 -2.566
1.543 -0.733
1.553 -1.008
1.562 -2.108
1.572 -1.466
1.582 -0.733
1.592 -1.558
1.602 -1.283
1.611 -1.191
1.621 -0.458
1.631 1.741
1.641 2.383
1.650 0.550
1.660 0.550
1.670 0.916
1.680 -0.550
1.689 -1.650
1.699 -1.008
1.709 -1.283
1.719 -1.283
1.729 -0.275
1.738 -2.016
1.748 -2.566
1.758 -1.008
1.768 -0.183
1.777 0.733
1.787 1.283
1.797 0.642
1.807 1.925
1.816 2.474
1.826 1.008
1.836 1.100
1.846 1.283
1.855 1.100
1.865 1.650
1.875 2.474
1.885 1.008
1.895 -0.550
1.904 -0.367
1.914 -1.925
1.924 -1.283
1.934 0.183
1.943 0.000
1.953 -0.550
1.963 -0.183
1.973 -0.550
1.982 0.458
1.992 1.833
2.002 -0.916
2.012 -1.925
2.021 -2.200
2.031 -2.566
2.041 -0.733
2.051 1.100
2.061 0.000
2.070 -1.650
2.080 -0.092
2.090 0.642
2.100 1.283
2.109 1.466
2.119 -0.916
2.129 -1.008
2.139 1.925
2.148 3.666
2.158 2.383
2.168 0.183
2.178 0.733
2.187 1.375
2.197 0.916
2.207 -0.183
2.217 -1.466
2.227 -0.733
2.236 -1.283
2.246 -0.367
2.256 1.558
2.266 1.466
2.275 0.458
2.285 0.000
2.295 0.916
2.305 0.642
2.314 0.275
2.324 0.092
2.334 1.008
2.344 0.367
2.354 -2.108
2.363 -1.100
2.373 0.000
2.383 -0.275
2.393 -2.658
2.402 -2.383
2.412 -0.275
2.422 0.733
2.432 3.024
2.441 4.582
2.451 5.132
2.461 4.216
2.471 1.100
2.480 -0.916
2.490 0.000
2.500 0.642
2.510 -0.367
2.520 -1.558
2.529 -1.375
2.539 -0.092
2.549 0.733
2.559 0.550
2.568 -0.183
2.578 1.466
2.588 1.008
2.598 -0.642
2.607 -0.275
2.617 0.092
2.627 -1.191
2.637 -2.200
2.646 -1.833
2.656 -0.275
2.666 1.925
2.676 0.275
2.686 0.916
2.695 1.283
2.705 -0.367
2.715 0.550
2.725 2.841
2.734 3.391
2.744 0.000
2.754 -1.191
2.764 -0.733
2.773 -0.642
2.783 0.000
2.793 0.275
2.803 0.458
2.813 -1.375
2.822 -0.092
2.832 2.016
2.842 3.391
2.852 5.132
2.861 4.766
2.871 3.757
2.881 3.208
2.891 2.383
2.900 0.550
2.910 -0.825
2.920 -1.008
2.930 -1.283
2.939 -0.458
2.949 0.550
2.959 -1.283
2.969 -2.474
2.979 -2.016
2.988 0.183
2.998 -0.275
3.008 -0.642
3.018 0.000
3.027 -1.558
3.037 -2.108
3.047 -2.566
3.057 -1.925
3.066 -1.375
3.076 -1.558
3.086 -1.191
3.096 -0.092
3.105 0.092
3.115 -1.008
3.125 -1.741
3.135 -1.925
3.145 -0.367
3.154 -0.092
3.164 -1.283
3.174 -1.191
3.184 -0.458
3.193 -0.092
3.203 -0.367
3.213 -1.833
3.223 -2.016
3.232 -1.375
3.242 0.092
3.252 1.650
3.262 0.550
3.271 -1.375
3.281 -0.642
3.291 -0.183
3.301 -0.458
3.311 -0.825
3.320 -0.183
3.330 -0.092
3.340 -1.008
3.350 -0.825
3.359 0.367
3.369 1.650
3.379 -0.092
3.389 -2.108
3.398 -2.200
3.408 -1.741
3.418 -1.283
3.428 -1.008
3.437 -0.275
3.447 1.100
3.457 0.092
3.467 -0.550
3.477 -0.916
3.486 -1.008
3.496 0.367
3.506 0.550
3.516 1.833
3.525 2.749
3.535 2.108
3.545 -0.092
3.555 1.191
3.564 0.367
3.574 -2.749
3.584 -2.933
3.594 1.100
3.604 3.116
3.613 3.757
3.623 0.733
3.633 -0.458
3.643 -0.642
3.652 -1.375
3.662 -1.100
3.672 0.367
3.682 -0.183
3.691 -2.016
3.701 -1.925
3.711 -0.183
3.721 1.283
3.730 0.367
3.740 -1.008
3.750 -1.741
3.760 -1.650
3.770 -0.916
3.779 -0.642
3.789 0.367
3.799 1.283
3.809 1.466
3.818 2.291
3.828 -0.458
3.838 -1.375
3.848 0.916
3.857 0.825
3.867 0.000
3.877 -1.833
3.887 -0.183
3.896 1.650
3.906 1.283
3.916 2.108
3.926 1.558
3.936 -1.375
3.945 -0.916
3.955 -0.092
3.965 -0.458
3.975 2.108
3.984 2.658
3.994 0.458
4.004 -0.733
4.014 -1.466
4.023 -2.108
4.033 -1.466
4.043 -0.183
4.053 -0.916
4.063 -1.650
4.072 -1.741
4.082 -1.833
4.092 -1.375
4.102 -0.825
4.111 1.191
4.121 0.275
4.131 -1.925
4.141 -0.183
4.150 -0.183
4.160 -1.925
4.170 -2.291
4.180 -1.925
4.189 0.825
4.199 0.733
4.209 -1.008
4.219 0.458
4.229 1.191
4.238 -0.092
4.248 -1.650
4.258 -1.466
4.268 -1.741
4.277 -1.741
4.287 -0.367
4.297 -1.375
4.307 -0.733
4.316 0.275
4.326 1.375
4.336 2.016
4.346 1.741
4.355 0.825
4.365 2.108
4.375 1.191
4.385 -0.825
4.395 -0.733