After taking the characteristic of embedded system into consideration, the traditional method based on the convolution for digital frequency weighting was analyzed. As the requirement of high precision and long filter coefficient, the calculation will increase dramatically. A novel method based on overlapping and adding DFT result was introduced. Analyzing and comparing the total computation of each kind of method. Simulation with MATLAB simulink toolbox and experiment on embedded system were implemented later. The result shows that both kinds of methods get the same result. The one based on overlapping and adding DFT result has better performance while the filter coefficient become longer and the selection principle was acquired for the situation the length of filter coefficient is known and both the length of filter coefficient and the length of frame are decided.