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

Piezo crystal osillator, whether piezo crystal and quazt crystal oscillator...

whether piezo crystal and quazt crystal oscillator are same?

Molecular chain, Molecular Chain (MIT, Princeton, Colorado) Consider a ...

Molecular Chain (MIT, Princeton, Colorado) Consider a one-dimensional chain consisting of N molecules which exist in two configurations, α, β, with corresponding energies  and

What is own-exchange routing, Q. What is Own-exchange routing? Distribu...

Q. What is Own-exchange routing? Distributed routing or own-exchange routing enables alternative routes to be chosen at intermediate nodes. Hence the strategy is capable of res

Cost of initial investment, Based upon the following inputs, propose the op...

Based upon the following inputs, propose the optimal course of action for this venture: Probability of success: 30%; probability of failure: 30%; base case probability: 40%

Cathode-ray tube, Q. Explain Cathode-ray tube? While the CRT display is...

Q. Explain Cathode-ray tube? While the CRT display is one of the oldest, it still remains one of the most popular display technologies. The raster-scanned display devices work

Determine the slip at which maximum torque, A three-phase, 220-V, 60-Hz, fo...

A three-phase, 220-V, 60-Hz, four-pole, wye connected induction motor has a per-phase stator resistance of 0.5 . The following no-load and blocked rotor test data on the motor are

Automotive wiring harness, what are the design consideration for electrical...

what are the design consideration for electrical wiring harness routing

How power amplifiers are classified, a. Describe briefly with suitable diag...

a. Describe briefly with suitable diagrams, how power amplifiers are classified with reference to operating point? b. Get the maximum efficiency of class A direct coupled power

Define byte assembler directive, What do you understand by DB assembler...

What do you understand by DB assembler directive?   DB (Define Byte): The DB directive explains by a byte-type variable (that is a variable that occupies one byte of memo

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