Unambiguous detection of signals superimposed on unknown trends is difficult for unevenly spaced data. Here. we formulate the Discrete Chi-square Method (DCM) that can determine the best model for many signals superimposed on arbitrary polynomial trends. DCM minimizes the Chi-square for the data in the multi-dimensional tested frequency space. https://parisnaturalfoodes.shop/product-category/illuminating-facial-polish/