1. Laboratory of Physical Layer
Mux/Demux

2. Physical Layer
Physical layer includes transmission media that is connected to the physical layer.
The first introduces the entities involved in the physical layer.
Transmission method consists of digital and analog.
Bandwidth Utilization: How to use the available bandwidth by using Multiplexing and Spectrum Spreading.
Switching can occur in any layer.

3. Intro. Of Physical Layer
Physical layer moves data in the form of electromagnetic signals across a transmission medium.
Data and signals can be either analog or digital.
Analog refers to an entity that is continuous;
digital refers to an entity that is discrete.

4. Intro. Of Physical Layer
Periodic analog signals can be used in data communication.
simple and
composite signals.
The attributes of analog signals consist of:
period,
frequency, and
phase.

5. Intro. Of Physical Layer
Nonperiodic digital signals can be used in data communication.
The attributes of a digital signal such as:
bit rate and bit length
How digital data can be sent using analog signals.
Baseband and broadband transmission.

6. Intro. Of Physical Layer
Transmission impairment.
attenuation,
distortion, and
noise
How they can impair a signal?

7. Intro. Of Physical Layer
How many bits per second we can send with the available channel.
Data rate depends on three factors:
The bandwidth available
The level of the signals we use
The quality of the channel (the level of noise)
Two theoretical formulas were developed to calculate the data rate:
Nyquist for a noiseless channel,
Shannon for a noisy channel.

8. (One link can have many n channels)
Multiplexing
Data link with limited bandwidths.
Bandwidth utilization:
multiplexing and
spectrum spreading
Link = physical path
Channel = the portion of a link that carries a transmission between a given pair of lines
(One link can have many n channels)
N lines share one link
Multiplexing

9. Multiplexing Techniques

10. FDM – Example

11. Wavelength-Division Multiplexing

12. Time-Division Multiplexing
The link is shown sectioned by time rather than by frequency. In the figure, portions of signals 1,2,3, and 4 occupy the link sequentially.

13. Multiplexer (Mux) Selects between one of N inputs to connect to output
log2N-bit select input – control input
Example: :1 Mux
2:1 multiplexer
symbol
Select input S
Truth table

14. Multiplexer Implementations
Logic gates
Sum-of-products form