I tried to find this topic in youtube, wikipedia and so many other sites but I can’t find this topic. If I found then these are very difficult to me and I can’t understand anything. This is very important to me and very urgent. Please Help me.
In the answer of your question….
It refers a range over which some measurable property of a physical phenomenon, such as the frequency of sound or electromagnetic radiation, or the mass of specific kinds of particles, can carry. Similar to a rainbow which is an spectrum of lights…Lights of different colors, hues and also different frequencies..
Ref: Continuous & Discrete Signals and Systems by Samir S. Soliman