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 do you mean by feedback in amplification, Q. What do you mean by Feedb...

Q. What do you mean by Feedback in amplification? Feedback :   Feedback in its broadest sense means that a certain amount of the output signal is "fed back" into the input. An

Lime, what is the formula of lime water

what is the formula of lime water

Explain thevenin and norton equivalent circuits, Q. Explain Thevenin and no...

Q. Explain Thevenin and norton equivalent circuits? For a linear portion of a circuit consisting of ideal sources and linear resistors, the volt-ampere (v-i) relationship at an

Write a control word for counter 1 of 8253 / 8254, Write a control word for...

Write a control word for counter 1 of 8253 / 8254 that selects the following options:  load least significant byte only, mode 5 of operation and binary counting.  Then write an ins

Magnetic flux and flux density, Magnetic flux and flux density Magnetic...

Magnetic flux and flux density Magnetic flux is the amount of the magnetic field (or the number of lines of force) formed by a magnetic source. The symbol represented magnetic

Variation of energy bands with alloy composition, Variation of Energy Bands...

Variation of Energy Bands with Alloy Composition The  band  structures  of  III-V  ternary  and  quaternary  compounds  modifies  as  their composition is varied. There

Switching characteristics, Switching Characteristics The switching  cha...

Switching Characteristics The switching  characteristic  of an IGBT  during  turn on and turn off time all  shown  in the sum of delay time  and rise time gives  the total  tur

Give a block diagram for amodulo-5 binary ripple counter, Q. Give a block d...

Q. Give a block diagram for amodulo-5 binary ripple counter using JKFFs and draw its timing diagram.

Calculate the ef?ciency of the induction generator, A three-phase, four-pol...

A three-phase, four-pole, 220-V, 60-Hz induction machine with a per-phase resistance of 0.5  is operating at rated voltage as a generator at a slip of -0.04, delivering 12 A of li

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