What Really Is In Carrier Signal ?

Replies

• 

  Jeffrey Arulraj

  Message signal energy is less and so if I transmit a message signal directly through a antenna my range will be really low
  
  So I multiply this signal with a carrier signal which has higher frequency than that of the message signal and so higher energy
  
  This high energy signal does not have any role in the noise produced during transmission
  
  The circuits used for modulation are sources of noise
• 

  Harshad Italiya

  ...Carrier signal is simply added with information signal so it can cover more distance. Information signal is used to be of low frequency so it will need High frequency carrier.
  
  I remember example given by my professor : One paper is your information and you want to throw it. It is not able to clear long distance. Now you put one stone inside paper and throw it. Simple !
• 

  Abhishek Rawal

  Okay, I know that carrier signal is used to superimpose on the information signal,withthe parameters like Frequency, Amplitude & Phase for FM,AM & PM respectively, so that it can cover long distance.
  
  My question is : Every signal in the world contains energy, so does carrier signal.
  So carrier signal must be containing something, you know.
  Some kind of energy, some kind of discrete energy. Which is nothing but noise, isnt it ?
  So, what I want to confirm is, aren't we intentionally sending noise signal only ?
  
  I hope you understood what i mean to say.
  I want to know that what the hell is it in Carrier signal ?
• 

  Harshad Italiya

  Yes you can call it noise but that is wanted noise and it has some defined nature so you can predict how long it can travell.
  
  While real noise it unwanted and have no any nature so you can't use it to carry information signal.
• 

  Harshad Italiya

  I have explained how carrier signal is used to carry information.
  Please see both case. You can say both carrier and noise have energy but see resulted modulated signal.
  
• 

  Anand Tamariya

  Abhishek Rawal

  Okay, I know that carrier signal is used to superimpose on the information signal,withthe parameters like Frequency, Amplitude & Phase for FM,AM & PM respectively, so that it can cover long distance.
  
  My question is : Every signal in the world contains energy, so does carrier signal.
  So carrier signal must be containing something, you know.
  Some kind of energy, some kind of discrete energy. Which is nothing but noise, isnt it ?
  So, what I want to confirm is, aren't we intentionally sending noise signal only ?
  
  I hope you understood what i mean to say.
  I want to know that what the hell is it in Carrier signal ?

  Think of it as encryption - the data is meaningful only if you have appropriate keys; else it's just noise.
• 

  Jeffrey Arulraj

  Well in short practically we call signal which does not match any criteria set for decrypting as noise
  
  Where as Carrier is noise which can be removed easily without any hinderance or trouble from the message signal