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 will the slipring voltage be in this case, A four-pole, three-phase, w...

A four-pole, three-phase, wound-rotor induction machine is to be used as a variable-frequency supply. The frequency of the supply connected to the stator is 60 Hz. (a) Let the r

What is pinch-off voltage, Q. What is Pinch - off voltage?  The reverse...

Q. What is Pinch - off voltage?  The reverse bias is relatively large near the source. As a result, the depletion region intrudes into the channel near the drain, and the effec

Switching characteristics during turn on , Switching characteristics during...

Switching characteristics during turn on A positive  gate  pulse  between  gate and  cathodeis sufficient to turn  on a thyrisotr. In  this period  thyristor  changes its stat

Find out form factor and peak factor, Find out Form factor and Peak factor:...

Find out Form factor and Peak factor: For the output of full wave rectifier, find out (a) RMS value, (b) Average value, (c) Form factor, and (d) Peak factor. S

Refrigeration and airconditioning, Ask question #Minimum 100 words acceptTh...

Ask question #Minimum 100 words acceptThere are various refrigeration systems employing various methods. State any seven (7) refrigeration systems, mention the method(s) employed t

Demonstrate the circuits operation , OBJECTIVES Use an NXT to control ...

OBJECTIVES Use an NXT to control the speed of a DC fan motor. You will us a potentiometer to set the speed and the second fan motor as feedback. Use the circuit from Lab 1 to

Addition of binary numbers , Addition of binary numbers Example:   Ad...

Addition of binary numbers Example:   Add  110010102 ( -510). and 00000101 2 (+5 10 ) Solution :                         Binary                                   signed

Inverting integrator circuit, Q. Consider the inverting integrator circuit ...

Q. Consider the inverting integrator circuit shown in Figure. Let C = 0.4µF and R = 0.1M. Sketch v o for a period of 0.5 s after the application of a constant input of 2 V at the

Applied electronics, What is coupling? Explain the types of coupling

What is coupling? Explain the types of coupling

parity flag - registers, Parity flag  - Registers If after  any arit...

Parity flag  - Registers If after  any arithmetical or logical operation if  number of  the accumulator  are even  parity  flag (P)  is set otherwise  reset.

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