Explain multiplexing systems, Electrical Engineering

Assignment Help:

Q. Explain Multiplexing Systems?

A multiplexing system is one in which two or more signals are transmitted jointly over the same transmission channel. There are two commonly used methods for signal multiplexing. In frequency-division multiplexing (FDM), various signals are translated to nonoverlapping frequency bands. The signals are demultiplexed for individual recovery by bandpass filtering at the destination. FDM may be used with either analog or discrete signal transmission. Time - division multiplexing (TDM), on the other hand, makes use of the fact that a sampled signal is off most of the time and the intervals between samples are available for the insertion of samples from other signals. TDM is usually employed in the transmission of discrete information. Let us now describe basic FDM and TDM systems.

Figure (a) shows a simple FDM system which is used in telephone communication systems. Each input is passed through a low-pass filter (LPF) so that all frequency components above 3 kHz are eliminated. It is then modulated onto individual subcarriers with 4-kHz spacing. While all subcarriers are synthesized from a master oscillator, the modulation is achieved with single sideband (SSB). The multiplexed signal, with a typical spectrum as shown in Figure (b), is formed by summing the SSB signals and a 60-kHz pilot carrier. The bandpass filters (BPFs) at the destination separate each SSB signal for product demodulation. Synchronization is achieved by obtaining the local oscillator waveforms from the pilot carrier. Telephone signals are often multiplexed in this fashion.

681_Multiplexing Systems.png

A basic TDM system is illustrated in Figure (a). Let us assume for simplicity that all three input signals have equal bandwidths W. A commutator or an electronic switch subsequently obtains a sample from each input every Ts seconds, thereby producing a multiplexed waveform with interleaved samples, as shown in Figure (b). Another synchronized commutator at the destination isolates and distributes the samples to a bank of low-pass filters (LPFs) for individual signal reconstruction.More sophisticated TDM systems are available inwhich the sampled values are converted to pulse modulation prior to multiplexing and carrier modulation is included after multiplexing. Integrated switching circuits have made the TDM implementation much simpler than FDM.


Related Discussions:- Explain multiplexing systems

What are the blocks of the microprocessor depends system, What are the bloc...

What are the blocks of the microprocessor depends system? The blocks of the microprocessor depends system are: The Memory and I/O System The Data Operating System

Calculation of receiving end voltage, Calculation of Receiving End Voltage ...

Calculation of Receiving End Voltage Consider the simple circuit shown in Figure. To find the voltage V 2 using analytical method:   P = I V 2 = 0.5      ..... (1)

Explain the applications of emitter follower, Q. Explain the applications o...

Q. Explain the applications of emitter follower. Because of high input impedance and low output impedance an emitter follower is capable of transferring maximum power from the

Cro, Diagram and explanation of cro

Diagram and explanation of cro

Electro magnetism, ELECTRO MAGNETISM: In this unit we learned about el...

ELECTRO MAGNETISM: In this unit we learned about electromagnetism and the relationship that presents between and magnetic flux and electric current. The way in which electric

Write out the general form of difference equation, Write out the General Fo...

Write out the General Form of Difference Equation? If the x[n] is the input and y[n] is the output of a linear time-invariant  system,  then  an  N  order  FIR  difference  equ

Evaluate the voltage gain, Q. On a CD amplifier R s = 4k?, µ =50 and r =35...

Q. On a CD amplifier R s = 4k?, µ =50 and r =35k?. Evaluate the voltage gain A v . A v = V o /V i = µRs / (µ+1)Rs + r

Allocative efficiency, Allocative Efficiency: A neoclassical concept refer...

Allocative Efficiency: A neoclassical concept referring to allocation of productive resources (labour, capital, etc.) in a manner that best maximizes well-being (or 'utility') of

Microprocessor, Memory map of tpa in a personal computer and explain such o...

Memory map of tpa in a personal computer and explain such of the areas in brief

OC AND SC TEST OF AN ALTERNATOR, WRITE THE PROCEDURE CONDUCT OC AND SC TEST...

WRITE THE PROCEDURE CONDUCT OC AND SC TEST OF AN ALTERNATOR TO FIND SYNCHRONOUS IMPEDENCE

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd