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Part A

1. The Nyquist theorem is one of the make up one’s minding factor in informations communicating. The fibre optics every bit good as the Cu wires are communicating mediums. Do you believe the theorem is valid for the fibre optics or for the Cu wires.

Autonomic nervous systems: – Nyquist theorem is related with informations rate of a communicating channal. The Nyquist expression has been designed for a noiseless channel. It defines the maximal informations rate of channel in theory. As per the expression BR=2*bandwidth*logL

Where BR is the Bit Rate, Bandwidth represents the bandwidth of the communicating channel and L represents the no of signals degrees used to stand for informations. Harmonizing to my sentiment this theorem is valid if the communicating mediums are fibre ocular as good the Cu wires in both instance will be certain spot rate bandwidth and the signal degrees which are the needed decision making factor for informations communicating by this theorem

The fiber optics as copper wires TOPICS SPECIFICALLY FOR YOU

2. Noise affects all the signals which are at that place in air. There are some pass oning transition techniques. Noise affects which of the transition technique the most.

Autonomic nervous systems: – Basically there are three transition techniques: –

  1. AM ( Amplitude Modulation )
  2. FM ( Frequency Modulation )
  3. PM ( Phase Modulation )

As in amplitude transition technique, it carries the signal that has the higher frequence than the information signal. In this by enforcing the lower frequence information signal on the bearer, the amplitude of the ensuing compound signal is made to change in the signifier of information signal.

So fundamentally these signals are affected by the noise signals that may add with the information signal and lead to disturbance in the signal.

As the strength of the signal lessenings with the distance traveled. It reaches to some minimal degree which is unacceptable for equal information. These signals need to be amplified but the amplifier adds the noise and affects the quality of the information.

But in instance of the frequence modulated moving ridges that are merely affected by the electrical perturbation.

In other words, AM is more noise susceptible than FM because you hear noise from lightning on AM wireless but non on FM wireless.

In world it is the high bandwidth of FM that allows the effects of noise to be minimized.

3. An linear signal carries 4 spots in each signal component. If 10,000 signal elements are sent per sec, find the Baud Rate and Bit Rate?

Autonomic nervous systems: – In This instance, r=4, s=10,000 we can happen the spot rate i.e. N utilizing the expression

S=N*1/r or N=S*r =10,000*4

( Bit rate ) N=40,000 bits per second

By utilizing expression ( S=N*1/r baud ) we can happen

Baud rate=40,000*1/4=10,000 baud

4. What are the grounds for the imperfectness caused in transmittal Medias? How the flawlessness can be measured?

Autonomic nervous systems: – The imperfectness in transmittal media is that the information is non same at finish point as it was at beginning. There is mismatching in the both signals.

There are three types of damage normally occur. These are fading, deformation and noise.

Attenuation- It is the loss of energy as the signal propagates outward on wires and fibres, the signal falls off as distance is increased. This is due to the opposition of the metal. That is the ground why wires get warm when current is passed from them. The sum of energy lost depends upon the frequence. To work out this job, devices called amplifiers are used.

Delay Distortion- It is caused by the difference in the operating velocity of different transporting constituents. For digital informations, fast constituents from one spot may catch show constituents of spot in front. This job consequences in out of order bringing of informations which leads to the mistakes.

Noise-It is the unwanted energy from the soures other than sender. Noises are of three types chief types: Thermal noise generated by negatron Conductor, XT caused by closed inductive copling and noice caused by spikes on the power line. The undermentioned line shows the consequence of noise on the signal

5. There are legion multiplexing techniques available. What in your sentiment is the most appropriate multiplexing technique for the fiber optics every bit good as Cu wires?

Autonomic nervous systems: – There are three chief techniques to implement multiplexing.

  1. Frequencies division multiplexing.
  2. Time division multiplexing.
  3. Wave division multiplexing.


Wavelength Division Multiplexing is done wholly in the optical sphere. Input electrical signals are each assigned a wavelength, which are combined on one fibre for transmittal and separated before being received.

Wave division frequence multiplexing is harmonizing to sentiment beckon division multiplexing is appropriate for fiber optics every bit good as Cu wires. In this signifier of multiplexing, assorted light moving ridges from different beginnings are combined to organize a composite visible radiation signal which is transmitted across the channel to the receiving system. At the receiver terminal, the composite signal interrupt down to different light moving ridges and these are delivered to their corresponding receiving system.

One may inquire about the mechanism of a WDM. Although the engineering s really complex, the thought is really simple. We want to unite multiple light beginnings into one individual visible radiation at the multiplexer and make the contrary as the demultiplexer. Combining and splitting of light beginnings are easy handled by prism.

6. While reassigning the information from the transmittal medium there are assorted facets of your informations acquiring tempered by other users? What in your sentiment is the most unafraid and insecure transmittal medium? Justify your reply with an illustration.

Autonomic nervous systems: – Radio transmittal media is more insecure than wired transmittal media because in wired, there is per centum of making the information in having terminal is more every bit compared to wireless, wireless medium is more prone to imperfectnesss, because these mediums uses the moving ridges or linear signal to direct the informations and these moving ridges are more prone to external noise and inclination of choping these moving ridges are more as compared to wired because these moving ridges plants on some frequence.

Transmission through Ethernet overseas telegram would bemore secure as it would be hard for interlopers to entree the user resources.

While reassigning the information from the transmittal medium there is possibility of informations acquiring tempered by others users because these clip engineering is traveling to be better, likewise the hacking activity is besides improved, so may be your informations is retrieve by another users and sometimes it happens due to the deformation in the transmittal medium whether it is wireless or wired transmittal medium.

Part B

1. Assume a watercourse is made of 10 0s. Encode this watercourse, utilizing following encoding strategies. How many can you happen for each strategy?

  • Unipolar
  • NRZ-L
  • NRZ-I
  • RZ
  • Manchester
  • Differential Manchester

Autonomic nervous systems: – Unipolar line coding-

this encoding utilizations tow electromotive forces phases to stand for informations. one of these electromotive force phases is ever nothing. in this line coding strategy, 1 ‘s are encoded as positive values and 0 ‘s are encoded as O ‘s value. The unipolar line coding strategy is simplest and really easy to implement. the unipolar line coding strategy for the watercourse of 10 nothing is given as-

2. Two channels, one with spot rate of 150kbps and another with a spot rate of 140kbps, are to be multiplexed utilizing pulse stuffing TDM with no synchronism spots. Answerer the followers:

  • What is the size of frame in spots
  • What is the frame rate?
  • What is the continuance of a frame?
  • What is the information rate?

Autonomic nervous systems: –

A· What is the size of frame in spots

Size of frame for 1st channel = 150,000 spots

Size of frame for 2nd channel =140,000 spots

A· What is the frame rate?

Frame rate for 1st channel= 150kbps

Frame rate for 2nd channel= 140kbps

A· What is the continuance of a frame?

Duration of frame for 1st channel=1/150,000 s

Duration of frame for 2nd channel=1/140,000 s

A· What is the information rate?

Data rate for 1st channel = 150,000 bits per second.

Data rate for 2nd channel =140,000 bits per second.

3. Contrast & A ; compare trying rate & A ; received signal?

Autonomic nervous systems: – comparing between the trying rate & A ; received signal

Sampling rate is the the figure of samples of the audio signal taken per second, and determines the high frequence cutoff the replayed sound of in which received signal is in the deformed signifier and it is reconstructed once more. Mathematically it is formulated as:

Fs & gt ; =2fm.

Where fs base for trying frequence and fm bases modulated frequence

in the sampling rate and simple standard signal is the that was received at finish after transition or demodulation to happen chief difference b/t the sampling rate and the standard signal is that in sapling encoding to happen because signal is reconstructed and in standard signal merely decrypting to happen

4. Synchronism is the job in informations communicating. Explain?

Autonomic nervous systems: – Synchronism is a job since in a communicating web there are assorted devices and terminuss connected and they all function or instead work at their ain velocities and have different bandwidths. So fundamentally the purpose is to bridge the spread between these devices. For illustration, if a sender has high velocity and is directing informations at its high velocity where as the receiving system unit is a slow-speed device, it wo n’t be able to accept the informations packet/frames at the high velocity at which it is being sent. So synchronization fundamentally trades with managing the information packages and seeing through that all that is sent is received right at the receiving system and there is no data loss. The happening of the latter will necessitate re-transmission and the bar of the same is by utilizing buffers that hold that high velocity informations package temporarily and so go throughing it onto the receiving system later. So we can state that synchronism is a job in informations communicating

5. Can seize with teeth rate be less than the pulsation rate? Why or why non?

Autonomic nervous systems: – yes, bit rate can be less than the pulse rate it is because of the ground that spot pulse represents the clip taken to direct the one signal of informations. The “bit rate” is used to depict the figure of spots sent over a communicating line in one second. Signal must be a group of informations spots so it is obvious that pulse rate is ever greater so the spot rate.

6. A signal is sampled each sample represents one of four degrees. How many spots are needed to stand for each sample? If trying rate is 8000 samples per second, what is the spot rate?

Autonomic nervous systems: – Harmonizing to the expression: –

Bit Rate=sampling rate*no of spots per sample

1 level=2 spot ;

In the given signal there are 4 degrees

So bit rate is=8000*8=64000 bits per second

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