A coaxial cable is a type of wire that contains a centre wire surrounded by insulation and a grounded shield of braided wire. The shield helps to minimize electrical and radio frequencies interference, a coaxial cable is used for television industry. Advantages:
1. Cheap to manufacture
2. Cheap and easy to install
3. Easy to modify
4. Good bandwidth
5. Good channel capacity
6. Noise immunity due to low error rate.
1. More expensive than a twisted pair.
2. The thicker the cable, the more difficult to work with
Fibre optic is a technology associated with the transmission of information as light pulses along a glass or plastic stand or fibber. There are two types of fibber modes: one is called single mode fibber and that is used for long distance and the other one is called multimode fibber which is used for short distance.
1. System performance
2. Greatly increased bandwidth and capacity
3. Lower signal attenuation
4. Immunity to electrical noise
5. Immune to noise
6. Less restrictive in harsh environments
7. Overall system economy
1. Fibber optic components are expensive
2. Fibber optic transmitters and receivers are still relatively expensive compared to electrical interfaces. 3. The lack of standardization in the industry has also limited the acceptance of fibber optics.
Infrared (IR) is a way to communicate to devices, it also cannot be seen with the naked eye. An example of use of infrared is when you want to change channels on your TV, you press a button on the remote and then it sends data to the TV receiver using Infrared (IR). This type of communication can only happen in close range communication.
1. Reliable in short range communications.
1. There should not be anything in the way of the transmitter (Remote) and the receiver (TV). 2. It can only be used in short distances.
Radio is a way of communicating over long distances and it is a very fast way, however it is not too reliable because the waves that get transmitted can be either absorbed or refracted by objects in the way.
1. Fast to send and receive messages
2. Cheaper than microwave communications
3. It is useful for long range and short range communications Disadvantages:
1. The wave can be refracted or absorbed by objects
Satellite is a specialized wireless receiver/ transmitter; they are used for weather forecasting, television broadcast, amateur radio communications, internet communications, and the global positioning system (GPS). Advantages:
1. High band width
2. Coverage over a large geographical area
3. Can be cheaper over long distances
1. Huge initial cost
2. Noise and interference
3. Propagation delay
Task 6.2 M2:
A transmission medium is used to carry signal from one device to another across a network. The choice of media depends on factors cost, quality speed and the distance the data has to travel to get to the receiving end. There are Different types of transmission methods and they are: * Coaxial Cable
* Fibre optic
Transmission method| Cost| Flexibility/Ease of installation| Reliability | Security | Data transfer rates| | Coaxial Cable | Cheap| Easy to install Very flexible | Reliable up to 200 meter | Not Secure | 10-100 Mbps| | Fibre optic| Cheap| Difficult to install | Reliable for long distance communications| Very Secure | 100+ Mbps| | Infrared| Cheap | Easy line of sight| Not reliable for long distance communication | Light could be intercepted | 4 Mbps| | Radio| Expensive | Difficult need a transmitter | Reliable for short and long distance communication| Not...