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

Metals, Metals, Semiconductors, and Insulators For electrons...

Metals, Semiconductors, and Insulators For electrons to move within an applied electric field there have to be states available to them. A totally filled band ca

Determine variation of large scale integration chips, Large scale integrati...

Large scale integration chips have between (A) Less than 10 components.         (B) 10 and 100 components. (C) 100 and 1000 components.       (D)  More than 1000 componen

Conductors for lines, Conductors for Lines The sizing of conductor mus...

Conductors for Lines The sizing of conductor must depend upon the load it is expected to serve and other factors, such as capacity required in future. Or else conductors/cable

Colpitts oscillator, how does a colpitts oscillator works an also explain t...

how does a colpitts oscillator works an also explain the principle

Calculate the hysteresis loss in joules per cycle, Q. In plotting a hystere...

Q. In plotting a hysteresis loop the following scales are used: 1 cm = 400 At / mand 1 cm=0.3 T. The area of the loop for a certain magnetic material is found to be 6.2 cm 2 . Calc

Define diffusion length, Define diffusion length: Sol. Diffusion len...

Define diffusion length: Sol. Diffusion length is defined as the distance, travelled by free carriers before recombining. It may also be defined as the average distance cove

Explain working of common drain amplifie, Q. Explain working of Common drai...

Q. Explain working of Common drain amplifie? When an ac signal drives the gate of JFET, it produces an ac drain current. It flows through Rs and produces an ac output voltage t

Complex number and variabls, what is tha lapelace transform of t^n please g...

what is tha lapelace transform of t^n please give me the answer i am so worried about iy???

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

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