Fast Fourier Transform and MATLAB Implementation with Code

Signals

In the fields of communications, signal processing, and in electrical engineering
more generally, a signal is any time‐varying or spatial‐varying quantity
This variable(quantity) changes in time
• Speech or audio signal: A sound amplitude that varies in time
• Temperature readings at different hours of a day
• Stock price changes over days
• Etc.

Signals can be classified by continues‐time signal and discrete‐time signal:

• A discrete signal or discrete‐time signal is a time series, perhaps a signal that
has been sample de from a continuous‐time si l gna
• A digital signal is a discrete‐time signal that takes on only a discrete set of
values