Biography, Science, Technology, Health, History Blogs

What is communication system? All modes of long distance communication system have been super ceded by electrical, electronic and optical modes. A communication system acts as a messenger. It consists of transmitter, communication channel and a receiver. A message signal has to be transformed appropriately to make it capable to transmission. The message signals for communication can be analog signals or digital signals. We cannot transmit an electronic signal in the audio frequency range (20 Hz to 20 kHz) over a long distance because. 1) The antenna or aerial should have a size comparable o the wavelength of signal (≈ 15 km)- which is too large. 2) Power of radiated 1/λ 2 . For good transmission, we need high powers and hence smaller wavelength or higher frequency. 3) Low frequency signals transmitted as such will get mixed up and there is no way to distinguish between them. Hence to transmit audio frequency signals, we use a high frequency signal called the carrier wave. The m...