Question

1. What is the relationship between a signal’s spectrum and its bandwidth? What is attenuation?
2. Compare and contrast DTE with DeE. What are the components of the DTE and DCE?
3. What are the different categories of modulation to change digital signals to analog signals?
4. Define channel capacity and what key factors affect channel capacity.
5. What distinguishes Frequency Division Multiplexing (FDM)? Time Division Multiplexing (TDM)? Statistical Time Division Multiplexing (STDM)? Wavelength Division Multiplexing (WDM)?
6. Why is multiplexing so cost-effective?

Answer 1

Answer:- The spectrum of a signal is the frequencies it contains while the bandwidth of a signal is the width of the spectrum

The spectrum of the signal can be seen as the frequencies which are contained by the signal, on the other hand, bandwidth can be defined as the width which is possessed by the spectrum.

Attenuation can be seen as the process of weakening of a signal over a period of time in the long distance.

Answer:-DTE can be defined as a device which plays the role of an information source or it facilitates the synchronization for the binary-digital data.

On the other hand, DCE is a device which is mainly helpful in providing the interface between the DTE. This device is also having the efficiency of receiving and transmitting the data in the various types of analog or digital signals related to a certain network.

Commonly the DTE device plays the role of a terminal or computer while the role of a modem is played by DCE. The main operations which are performed by DCE in data station are converting the signals, coding, line clocking and it can also form the part of DTE system.

The various components of DTE are as below:-

Stream-In traffic handler

Data requester

Data Handler

Snoop Handler

Components of DCE are as below:-

IDL(Interface definition language),

Name service API,

UUID generator

Authenticated RPC

RPC runtime ( which implements TCP/IP or UDP)

Answer:- Digital to analog conversion can be done by the following modulation methods:-

Amplitude shift keying:- here the amplitude of the carrier signal is changed

Frequency Shift Keying:- The data is represented with the help of changing the frequency of the carrier signal.

Phase Shift Keying:- In this method in order to reflect two or more signal elements, the phase of the carrier signal is changed

Answer:- Channel capacity can be defined as a maximum extent of the traffic or signal which can be transmitted or shifted with the help of a certain infrastructure of the channel. This is commonly used in the field of computers, electrical engineering.

In other words, channel capacity can be seen as the maximum amount of data which can be transmitted over a certain communication channel with highest reliably.

The various factors which can affect the channel capacity are the data rate, bandwidth, noise and error rate