ABSTRACT
This chapter discusses the simplest finite impulse response (FIR) design techniques, which are based simply on starting with a desired transfer function in the form of a discrete Fourier transform (DFT) and then obtaining the filter weights via the inverse DFT. Because many different applications take the form of one of the four filters—lowpass, highpass, bandpass, and bandstop. Compared with infinite impulse response filters, FIR filters have advantages and disadvantages. FIR filters have other advantages as well. Having only zeros, they are not unstable as long as the weights are finite. The Kaiser window requires more discussion, but it is worth the trouble, because its properties lead to superior FIR filter designs. The Blackman window is a modulated version of the Hanning window. Blackman window has a relatively wide main spectral lobe and lower side lobes, resulting in a smoother FIR power gain function with longer transition between passband and stopband.
