Real and imaginary signals definition

In signal processing "real" denotes a signal component that is in phase with (i.e. has a 0° phase shift from) some reference signal. Imaginary denotes a signal component that is in quadrature with (i.e. has a 90° phase shift from) the same reference signal.

1. What is real and imaginary signal?
2. What is real signals?
3. What is real and imaginary components?
4. What are the different types of signals?
5. What are real valued signals?

What is real and imaginary signal?

Real and Imaginary Signals

Example: If x(t)= 3 then x*(t)=3*=3 here x(t) is a real signal. If x(t)= 3j then x*(t)=3j* = -3j = -x(t) hence x(t) is a odd signal. Note: For a real signal, imaginary part should be zero. Similarly for an imaginary signal, real part should be zero.

What is real signals?

A real signal at any given time takes its value in the set of real numbers, and a complex signal takes its value in the set of complex numbers.

What is real and imaginary components?

In a complex number z=a+bi , a is called the "real part" of z and b is called the "imaginary part." If b=0 , the complex number is a real number; if a=0 , then the complex number is "purely imaginary."

What are the different types of signals?

Two main types of signals encountered in practice are analog and digital. The figure shows a digital signal that results from approximating an analog signal by its values at particular time instants. Digital signals are quantized, while analog signals are continuous.

What are real valued signals?

A real-valued signal is just a complex signal where all the imaginary components of all the complex values are strictly zero. Real valued signals have one degree of freedom. Complex signals are often used to represent signals or data with 2 degrees of freedom (magnitude and phase, or kinetic and potential energy, etc.)