1. Time-division Multiplexing (Digital)
1.1. combining several low data-rate channels into one high-rate one
1.2. FDM
1.2.1. bandwidth shared
1.3. TDM
1.3.1. time shared
1.3.2. SYNCHRONOUS
1.3.2.1. each input occupies 1 time slot & occupies 1 output time slot
1.3.2.2. time slots grouped into frames ( 1 complete cycle of time slots )
1.3.2.3. system with n input lines, each frame has n slots
1.3.2.4. each slots allocated data from specific input line
1.4. link sectioned by time
1.5. STATISTICAL
1.5.1. TDM - slots are dynamically allocated to improve bandwidth efficiency
1.5.2. Multiplexing - no. of slots in each frame is < no. input lines
1.6. EMPTY SLOTS
1.6.1. one of the input lines has no data to send
1.6.2. one of the input line has discontinuous data
1.7. DATA RATE MANAGEMENT
1.7.1. techniques to handle disparity in input data rates
1.7.2. MULTILEVEL MULTIPLEXING
1.7.2.1. data rate of an input line is multiple of others
1.7.3. MULTIPLE-SLOT ALLOCATION
1.7.3.1. more efficient to allot > 1 slot in a frame to a single input line
1.7.4. PULSE STUFFING
1.7.4.1. bit rates of sources are not multiple integers of each other
2. Wavelength-division Multiplexing (Analog)
2.1. multiplexing & demultiplexing involve optical signals transmitted through fiber-optic cable
2.2. light - multiplexed & demultiplexed (prism)
2.3. DWDM (dense WDM)
2.3.1. multiplex very large no. of channels
2.3.2. spacing channels closer to one another
2.3.3. achieves greater effiiciency
3. Frequency-division Multiplexing (Analog)
3.1. bandwidth of link (Hz) > combined bandwidths of the signals
3.2. combines analog signals become 1 composite signal
3.3. channels separated by strips of unused bandwidth (guard bands) to prevent signals from overlapping
3.4. Analog Hierarchy
3.4.1. maximize the efficiency of company insfrastructure
3.4.2. AT&T
3.4.2.1. Group
3.4.2.2. Super groups
3.4.2.3. Master groups
3.4.2.4. Jumbo groups
3.5. Other App
3.5.1. cable televison
3.5.2. radio broadcasting
3.5.3. coaxial cable used ( bandwidth approximately 500 MHz )