Frequency Division Multiplexing (FDM)

Frequency Division Multiplexing

Definition

Frequency Division Multiplexing (FDM) is a technique where multiple signals are combined for transmission over a single communication channel by assigning each signal a different carrier frequency.

Detailed Explanation

Working Principle

  • Divides available bandwidth into separate frequency bands
  • Each signal modulated with different carrier frequency
  • Signals transmitted simultaneously
  • Guard bands prevent interference

Implementation Process

  1. Signal Separation

    • Each input signal assigned unique frequency band
    • Guard bands added between channels
    • Bandwidth divided into non-overlapping ranges
  2. Modulation

    • Each signal modulated with unique carrier frequency
    • Maintains signal integrity
    • Prevents cross-talk

Applications

  • FM radio broadcasting
  • Cable television
  • Satellite communications
  • Traditional telephone systems

Advantages & Limitations

Advantages:

  • Continuous transmission
  • No synchronization needed
  • Simple implementation
  • No buffering required

Limitations:

  • Bandwidth inefficiency
  • Crosstalk possible
  • Limited number of channels
  • Guard bands waste bandwidth

Notes

References