Chapter 4 : Multiplexing

1. Definition :

1.1. A set of techniques that allows the transmission of multiple signals across a single data link

2. Data Rate Management

2.1. Multilevel Multiplexing

2.1.1. Used when data rate of all input line is a multiple of others

2.2. Multiple-slot Multiplexing

2.2.1. More efficient to allot > 1 slot in a frame to a single input line

2.3. Pulse Stuffing Multiplexing

2.3.1. Bit rates of sources are not multiple integers of each other

3. Frequency-division Multiplexing

3.1. Analog

3.2. The bandwidth of a link (Hz) is > the combined bandwidths of the signals

3.3. Combines analog signals become one composite signal

3.4. Channels seperated by strips of unused bandwidth to prevent signals from overlapping

4. Wavelength-division Multiplexing

4.1. Analog

4.2. The multiplexing & demultiplexing involve optical signals

4.3. Light are multiplexed & demultiplexed by using aprism

4.4. Can multiplex a very large number of channels by spacing channels closer to one another

5. Time-division Multiplexing

5.1. Digital

5.2. Combines several low data rate channels into one high rate

5.3. FDM - bandwidth is shared TDM - time is shared

5.4. Synchronous TDM

5.4.1. each input occupies one time slot and occupies one output time slot

5.4.2. grouped into frames

5.5. Statistical Time-division Multiplexing

5.5.1. slots are dynamically allocated

5.5.2. the number slots in each frame is less than the number of input lines