Bandwidth utilization
- 1. BANDWIDTH UTILIZATION:MULTIPLEXING AND SPECTRUM SPREDING When the bandwidth of a medium linking two devices is grater than the bandwidth need of the devices, link can be shared
- 2. MULTIPLEXING Multiplexing is a set of techniques that allow the simultaneous transmission of multiple signals across a data link
- 3. In above multiplexed system, n lines shared the bandwidth of one link. The above figure show the basic format the multiplexed system. The lines on the left direct their transmission stream to a multiplexer(MUX),which combine into a single stream(many to one). At the receiving end the stream is fed into a demultiplexer(DEMUX),which separate the stream back into its components transmission(one to many). In the figure the link can have many channals(n)
- 4. Categories of multiplexing There are three basic multiplexing techniques: 1.Frequency-Devision Multiplexing(analog) 2.Weveleanth-Division Multiplexing(analog) 3.Time-Division Multiplexing(digital)
- 5. Frequency-Division Multiplexing FDM is an analog technique that can be applied when the bandwidth of a link is grater than the combined bandwidth of signals to be transmitted.In FDM , signals generated by each sending device modulate different carrier frequencies. These modulated signals are then combined into a signal composite signal that an be transported by the link.Carrier frequencies are seperated by sufficient bandwidth to accommodate to modulated signal. Channal can be seperated by strips of unused bandwidth –GUARD BANDS-to prevent signal for overlapping. In addition , carrier frequencies must not interfere with the original data frequencies
- 6. FDM is an analog technique that combine the analog signals. Carrier Signal:-in analog transmission, the sending devices produce a high frequency signal that act as a base for the information signal,this base signal is called carrier signal or carrier frequency. Composite signal:-A composite signal is combination of sine wave who have many types of information
- 7. Waveleangth-Division Multiplexing WDM is designed to use to high data rate capability of fiber optic cable.The optic fiber data rate is higher than data rate of transmission cable but using a fiber optic cable for a single line wastes the available bandwidth.
- 8. TIME DIVISION MULTIPLEXING TDM is a digital proccess that several connection to share the high bandwidth of link.Instead of a sharing portion iof the bandwidth as in FDM.
- 9. TDM are two types(as signal transmission based) (TDM is a digital multiplexing technique for combining several low rate channels into one high rate one ) 1. Synchronous TDM
- 11. DATA RATE MANAGEMENT:- One problem with TDM is how to handle a disparity in the input data rates. 1.Multilevel multiplexing 2.Multiple Slot allocation 3.Pulse Stuffing
- 14. PULSE STUFFING
- 15. SOME IMPORTANT HEADINGS ANALOG HIERARCHY DIGITAL HIERARCHY
- 16. ANY QUESTION…?
- 17. THANK YOU.. €…