This lab introduces a practical application where sinusoidal signals are used to transmit information: a
touch-tone dialer. Bandpass FIR filters can be used to extract the information encoded in the waveforms.
The goal of this lab is to design and implement bandpass FIR filters in M ATLAB , and to do the decoding
automatically. In the experiments of this lab, you will use

`firfilt()`

, or `conv()`

, to implement filters and
`freqz()`

to obtain the filter’s frequency response. 1 As a result, you should learn how to characterize a filter
by knowing how it reacts to different frequency components in the input.
[Files]
The goal of this lab is to learn some methods for designing practical FIR filters in Matlab. These filters
will have a finite number of coefficients, and a frequency response that approximates an ideal frequency
response shape.