Networks Communications

Baseband
This is a type of data transmission. This type of transmission sends both a digital and analogue signal over one single multiplex channel. This means there is one single line or channel that can transfer both analogue and digital signals. Examples of this would be an Ethernet or LAN (local area network). Baseband transmission uses TMD which is a Time division multiplexing, this means it sends bits of data at different times along the full bandwidth.

Broadband
This is a type of data transmission. This is a faster type of data transmission that carry several channels at once as the other types including base band struggle to send one signal at once, broadband can transfer many signals at once over a vast network

Modem




A modem is a device used to convert a digital signal into an analogue so data can be transferred easily. When data is stored within a computer it is stored in a digital form but when it is transferred down a telephone it has to be changed to an analogue signal to go down telephone line. A Modem is a piece of hardware using to pass information from one pc to another using a telephone line. The modem acts like a telephone and allows two computers talk to each other. A modem can transfer data at 30,000 bits per second

Digital Signalling
A digital signal is when binary numbers are transmitted as a signal this signal only works using 2 numbers 0 and 1. Unlike the analogue signal, digital signal switch on and off. This is also known as a pulse wave. This wave can only be positive and negative

Analogue waves
An analogue signal is like a wave that represents the vibrations of the sound. This means that the information can have an unlimited amount of numbers. The analogue signal is an continuous.

This is how it works
From the computer the signal is sent as a digital pulse wave then it is converted into an analogue wave to travel down the phone line then it is converted back to a digital to go back to the receiving computer.

Amplitude modulation




Amplitude modulation
Amplitude modulation is a type of modulation that is used within the radio transmission to send audio sounds and messages For example, radio uses AM to transmit an audible sound of say 400 Hz by varying the amplitude of a radio signal with frequency 100,000 Hz. This is means of loading information onto a carrier wave by modulating its height.


Frequency modulation
Frequency modulation a method of transmitting information on radio waves by encoding the information as a change in frequency or number of waves per second. This is also used in radio transmission (FM).

The advantages and disadvantages of using baseband transmission

Advantages
Cheap to setup
Fast data transfer

Disadvantages
Can only transmit over a small area


The advantages and disadvantages of using broadband transmission

Advantages
Can transmit data over a large area
Fast to transfer the data

Disadvantages
Can be more expensive

Unicast
Unicast is a type of communication within a network that is sent by a single sender and is receive by only one single receiver. An simple example of this is a simple email from one person to another

Multicast
This is another way of communicating over the network. Where as the unicast was sending a message from a single sender to a single receiver, multicast is sending a message to a specific group. So it is sending a message from a single sender to a group of receivers. An example of this is sending an e-mail message to a mailing list Teleconferencing and videoconferencing also use multicasting, but require more robust and technical networks.

Broadcast
This is another type communication over a network. Broadcast simply sends a message to all of the systems within the network. Whereas the other two types of communication sends the message to specific recipients where are this one sends it to all of the systems within the network. Broadcasting is a useful feature in e-mail systems.