利用最小二乘原理建立了趋势项的一般模型，并利用MATLAB软件强大的矩阵计算功能，对一个含有非线性趋势项的周期信号进行了趋势项消除，并得到了预期效果。-Using the least squares principle to establish a trend term, the general model and the use of MATLAB software is powerful matrix calculation function, for a linear trend term with periodic signals the trend for elimination, and get the desired effect.