Q & A
Q1: Define bandwidth
Answer: Bandwidth refers to the maximum capacity of a transmission media or channel that can be allocated.
Q2: What are the types of transmission based on bandwidth usage?
Answer: Two types i.e.
i. Baseband Transmission
ii. Broadband Transmission
Q3: What is baseband? What are its important features?
Answer: Baseband transmission is a transmission of signals without modulation. It uses the entire bandwidth for a single channel. Baseband is commonly used for digital signaling, but it can also used for analog signal. Signals flow in the form of discrete pulses of electricity or light i.e. 1s and 0s. The entire spectrum of the cable is consumed by the signal. This scheme does not allow frequency-division multiplexing.
Important features of baseband transmission are:
· Baseband transmission use digital signal over a single frequency.
· Signals flows in the form of discrete pulses of electrical or light.
· The digital signal uses the complete bandwidth of a single channel.
· Baseband systems use repeater.
· No modem is required.
· Used for a short distance.
· Commonly use in Local Area Networks.
Q4: What are the advantages of using baseband cables?
i. Low maintenance cost.
ii. Simple to install and tap.
iii. Better resistance to signal noise over longer distance.
Q5: What are the disadvantages of using baseband cables?
i. Limited distance and topology.
ii. Low security, easily tapped.
iii. Difficult to make major changes to the cabling topology.
iv. Cable cost is higher than that of twisted pair.
Q6: Define broadband transmission. Write down its salient features.
Answer: Broadband transmission provides the ability to divide the entire media bandwidth into multiple channels. It provides data transfer by means of analog signals or (radio- frequency) signals or digital signals. each channel can carry a different analog signal, broadband networks
support multiple simultaneously conversations over a single transmission medium. Digital signals are passed through a modem and transmitted over one of the frequency bands of the cable. Broadband systems use amplifiers to regenerate analog signals at their original strength. Used for long distance communication using switching or leased lines from public carriers.
1. Broadband systems use analog signals both continuous and discrete.
2. Broadband signal flow is unidirectional. Therefore there must be to paths for data flow in order for a signal to reach all devices.
3. Widely used in WANs (Wide Area Networks). Also used for some LANs based on cable TV technology.
4. Broadband systems use amplifiers to regenerate analog signals at their original strength.
Q7: What are different types of broadband systems?
1. Dual Cable System
2. Single Cable System
Q8: What are the advantages of fibre optic cables over co-axial cables?
1. High bit rates.
2. Lowest transmission loss over longer distance.
3. No subject to interference.
4. Good for network “backbones” point-to-point.
5. Supports voice, data, video.
6. Difficult to tap.