MOD 8 UNIT 2A

MULTIPLEXING

• Process of combining two or more users into one composite (combined) signal for simultaneous transmission to distant end 

• Key is to have more transmitting bandwidth than total amount needed by all users combined 

• Most defense communication systems today use time based multiplexer 

• Time Based Multiplexers transmit entire bandwidth or frequency every second

TYPES OF MULTIPLEXING 

• Frequency Division Multiplexing (FDM)

  • Based on Frequency 

• Time Division Multiplexing (TDM)

  • Assigning time slot 

FREQUENCY DIVISION MULTIPLEXING (FDM)

• USES MODULATION TO CREATE ANALOG SIGNAL (FOOT STOMP)

• Older of the two

TIME DIVISION MULTIPLEXING

• Most communications use TDM, NOT FDM

• Considered ROUND ROBIN use of a frequency 

• Subidives intelligence across bandwidth

• Interleaves the smaller portion together when it’s all transmitted to the distant end 

• De multiplexer is a switching device synchronized to local transmit multiplexer 

DEMULTIPLEXING 

• Breaks apart the aggregated signal into their own respective outputs/channels

• THE TYPE OF MISSION DICTATES WHAT MULTIPLEXER YOUR NETWORK HAS