Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
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.
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.
Q. Explain the theory of thermal runaway? The maximum average power Pdmax which a transistor can dissipate depends upon the transistor construction and may lie in the
Explain How to Represent Power Lines? The equivalent circuit of a power line depends on the length of the line and on the accuracy of the model required. In general, any power
What is expanded memory system? EMS: The area at location C8000H-DFFFFFH is frequently open or free. Such area is used for the expanded memory system into a XT or PC system, or
Q. Describe about transmission-line voltage regulation? The transmission-line voltage regulation (TLVR) is the ratio of the per-phase voltage drop between the sending-end and r
The following data apply to a 100-kW, 250-V, six-pole, 1000-r/min long-shunt compound generator: no-load rotational losses 4000 W, armature resistance at 75°C = 0.015 , series-fie
How address and data lines are demultiplexed in 8085? AD0-AD7 lines are multiplexed and the lower half of address A0-A7 is available only during T1 of the machine cycle. This
Q. For a 6-bit weighted-resistor D/A converter, if R is the resistor connected to the MSB, find the other resistor values needed, and calculate the maximum analog output voltage, t
3-phase 3 wire meter with CT and MD It is exactly such as 3-phase 4 wire meter and works on the similar principle. It is also used in the similar way and under the similar cir
Q. (a) Let a unit impulse of voltage v(t) = δ(t) be applied to a series combination of R = 20 and L = 10 mH. Determine the current i(t)in the series circuit. (b) Repeat (a) for
What is tunnel effect? Discuss the Alpha decay as an example of tunnel effect. Prove that tunneling increases on decreasing the height and width of the barrier. Explain what do you
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!
whatsapp: +91-977-207-8620
Phone: +91-977-207-8620
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd