Mathematical operations on analog signals are unambiguous. We require that the signals are defined over the same time interval when using operations such as addition, multiplication, division and so on.
Inside Collection (Course): Information and Signal Theory
Summary: Analog signals
The signals signals and relations presented in this module are quite similar to those in the Discrete time signals module. So do compare and find similarities and differences!
Mathematical operations on analog signals are unambiguous. We require that the signals are defined over the same time interval when using operations such as addition, multiplication, division and so on.
The delta function is a peculiar function that has zero duration, infinite height, but still unit area! Mathematically we have the following two properties
(We assume that
The unit step function is equal to zero when its argument is negative and equal to one for nonnegative arguments, see Figure 1 for plots.

The trigonometric functions are central
to signal processing and telecommunications. They are defined as follows, where
The complex exponential function is central
to signal processing and some call it the most important signal.
The complex exponential function can be written as a sum of its real and imaginary part.
Take a look at • Introduction; • Discrete time signals; • Discrete vs Analog signals; • Frequency definitions and periodicity; • Energy & Power; • Exercises ?