Digital-filters

  A filter is a system which modifies some special frequencies reletive to the others. As a result it is applicable in some applications when it is necessary to have different gains & phase shifts at different frequencies to perform specific filtering tasks. For example in an audio file which is corrupted by noise it is convinient to use a filter to cancel those frequencies which are affected by noise and consequently having a better sound quality. During this MATLAB experiment we are trying to cancel the noise frequencies out of the original signal frequencies to get the original signal. Due to do this task, different types of filters such as FIR and IIR filters are used. In FIR filters, we use two type of common windows such as fixed window like Hanning and adjustable window like Kaiser. In IIR filters four different types of filter such as Butterworth, Chebyshev I, Chebyshev II, Elliptic are used.