Signal & System is a topic of study, we all know that.But, When some one ask the obvious 'easy' question 'What is signal?' we start to think. Well, for those who still wonder why should we study Signal & System lets take a look at what Signals & Systems really are.
Signal : By definition it is a physical quantity that varies with time and space or any other variable.
By the word 'physical quantity' we mean that Signals are not only a theoretical or mathematical thing.They have real world existence. If you look more closely you will find them everywhere.Your computer, your home appliances everything runs on electricity, which is, by definition a signal.If you talk your vocal chord creates signals (speech signals) and when you are looking at this post you are looking at signals!So, signals are everywhere and that is why there is a need to study them.
The above picture is a simple sinusoidal signal ( a cosine signal to be precise ).For the purpose of analysis this is how we represent a signal graphically and by analysis I mean we can get useful information about the signal from the graph itself. Like for an example, in this graph we can see that the signal has a positive amplitude of 1.
System: It is a physical device that gives an output signals for a given input signal.
Again systems are in abundance in our nature. For instance, your vocal chord can be thought of as a System.You push air into your vocal chord and sound comes out. So in this case your vocal chords performs some operation on the air and creates vibration as output.Your computer is a system.You click your mouse and for that given input your computer performs some tasks as an output.If, I am to give every possible example of an system then i am afraid this single post would have to be pages long. Fortunately we have a definition and every physical object that fits into that definition, is a System .
Above picture is an example of how systems are represented by block diagrams. In this diagram one can see that there is and input signal and for that there is an output signal.
Signal & System is a topic, very popular among Communication engineers .It deals with the working and mathematical aspects of different signals and systems.
Signal : By definition it is a physical quantity that varies with time and space or any other variable.
By the word 'physical quantity' we mean that Signals are not only a theoretical or mathematical thing.They have real world existence. If you look more closely you will find them everywhere.Your computer, your home appliances everything runs on electricity, which is, by definition a signal.If you talk your vocal chord creates signals (speech signals) and when you are looking at this post you are looking at signals!So, signals are everywhere and that is why there is a need to study them.
The above picture is a simple sinusoidal signal ( a cosine signal to be precise ).For the purpose of analysis this is how we represent a signal graphically and by analysis I mean we can get useful information about the signal from the graph itself. Like for an example, in this graph we can see that the signal has a positive amplitude of 1.
System: It is a physical device that gives an output signals for a given input signal.
Again systems are in abundance in our nature. For instance, your vocal chord can be thought of as a System.You push air into your vocal chord and sound comes out. So in this case your vocal chords performs some operation on the air and creates vibration as output.Your computer is a system.You click your mouse and for that given input your computer performs some tasks as an output.If, I am to give every possible example of an system then i am afraid this single post would have to be pages long. Fortunately we have a definition and every physical object that fits into that definition, is a System .
Above picture is an example of how systems are represented by block diagrams. In this diagram one can see that there is and input signal and for that there is an output signal.
Signal & System is a topic, very popular among Communication engineers .It deals with the working and mathematical aspects of different signals and systems.
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