The document discusses designing FIR filters using windowing techniques. It describes using a rectangular window to design a high pass FIR filter. The key steps are: 1) Obtaining the Fourier coefficients of the desired frequency response, 2) Multiplying the coefficients by a window function to reduce oscillations, 3) The windowed coefficients give the impulse response of the FIR filter. Designing a filter using a rectangular window results in significant sidelobes in the frequency response. The document then discusses using a Kaiser window to design a low pass FIR filter and analyzing the effect of different beta values on the filter characteristics.