Multiplexing
CHAPTER 4

Outline * Frequency Division Multiplexing(FDM) * Synchronous Time Division Multiplexing * Statistical Time Division Multiplexing * Asymmetric Digital Subscriber Line(ADSL)

Multiplexing * Set of techniques that allows the simultaneous transmission of multiple signals across a single link * allows several transmission sources to share a larger transmission capacity

Link = physical path
Channel = portion of a link that carries a transmission between a given pairs of lines

2 CATEGORY OF MULTIPLEXING

WDM FDM TDM ADSL
Frequency Division Multiplexing

* FDM – numerous signals are combined for transmission on a single communications line or channel. Each signal is …show more content…
Solution
We can answer the questions as follows:
1. The duration of 1 bit is 1/1 Kbps, or 0.001 s (1 ms).
2. The rate of the link is 4 Kbps.
3. The duration of each time slot 1/4 ms or 250 ms.
4. The duration of a frame 1 ms.

Interleaving

• switches are synchronized and rotate at the same speed but opposite direction
•process of sending a unit data onto the path when the connection on the multiplexing and de-multiplexing is open
Example 6
Four channels are multiplexed using TDM. If each channel sends 100 bytes/s and we multiplex 1 byte per channel, show the frame traveling on the link, the size of the frame, the duration of a frame, the frame rate, and the bit rate for the link.
Solution
The multiplexer is shown in Figure 6

Example 7
A multiplexer combines four 100-Kbps channels using a time slot of 2 bits. Show the output with four arbitrary inputs. What is the frame rate?
What is the frame duration? What is the bit rate? What is the bit duration?
Solution
Figure 7 shows the output for four arbitrary inputs. Synchronous Time Division Multiplexing

* Possible when data rate of medium exceeds data rate of digital signal to be transmitted * Multiple digital signals interleaved of each signal in time during transmission * Interleaving can be at bit level of blocks * Time slots preassigned to sources and