Signal Modulation

Syllabus :GS 3/Science and Tech

In News

  • Signal modulation streamlines the technology needed to transmit information, such as news on TV or music on the radio. 

Modulation 

  • Modulation, in electronics, technique for impressing information (voice, music, pictures, or data) on a radio-frequency carrier wave by varying one or more characteristics of the wave in accordance with the information signal. 
  • There are various forms of modulation, each designed to alter a particular characteristic of the carrier wave. 
  • Modulation allows multiple signals to coexist without interference.
    • Digital transmissions are less affected by static noise, enhancing communication technologies.

Modulation Types:

  • Frequency Modulation (FM): It involves changing the frequency of the waves to convey information (e.g., Morse code with closely spaced waves for dots).
    • FM is widely used in FM radio broadcasting, where the quality of sound is crucial. It provides better resistance to noise and interference compared to AM.
  • Amplitude modulation (AM) : It involves varying the amplitude of the waves while keeping frequency constant (e.g., using heavy and light stones to represent dots and dashes).
  • Phase Modulation (PM): It changes the phase of waves to encode messages, allowing for clearer digital transmission since it’s less affected by amplitude fluctuations
    • PM is used in certain digital communication systems and radar applications.

Uses of Modulation:

  • Radio Broadcasting: Both AM and FM modulation are used for radio transmission. AM covers long distances but is susceptible to interference. FM provides better sound quality and is ideal for music.
  • Television Broadcasting: TV signals are also modulated (usually using vestigial sideband modulation).
    • This allows us to watch our favorite shows with clear audio and video.
  • Cellular Communication: Mobile phones use various modulation techniques to transmit voice and data over cellular networks.
  • Wireless Internet (Wi-Fi): Wi-Fi signals are modulated to carry data wirelessly between devices.
  • Satellite Communication: Satellites use modulation to relay signals across vast distances.
Do you know ?
– Digital transmission uses discrete signals (0s and 1s), while analog transmission uses continuous signals.
– PM is digital and better for data transmission, whereas AM and FM are used for analog radio and TV broadcasts.

Source :TH