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. Illustrate Differential phase-shift keying?
In order to eliminate the need of a local carrier, DPSK has been developed in which the receiver uses the received signal to act as its own carrier. Figure shows the functions of a DPSK system in which the leftmost product operation along with 1-bit delay is the differential encoder. The digital signal d(t) is a polar waveform of levels ±1, corresponding to binary digits 1 and 0, respectively. The output signal a(t) from the differential encoder PSK-modulates a carrier to produce the DPSK signal sDPSK(t). The product device followed by the wide-band low-pass filter acts as the coherent detector. The two inputs to the product device are obtained from the output of a filter matched to the input pulse in a single bit interval. Note that the 1-bit delayed input to the product device serves the purpose of the local oscillator for the coherent detector; that is to say, the DPSK waveform in a given bit interval serves as its own local-oscillator signal in the following bit interval.
In Figure, si(t) is the signal component of the matched filter output, and sd(t)isthe signal component of the detector output. If the phases of both si(t) and si(t - Tb) are the same, sd(t) is then a positive voltage; if their phases differ by π radians, sd(t) will then be a negative voltage. These voltages will have maximum amplitudes at the sample time at the end of the bit interval. Because the sign of the voltage at the sampler depends upon the phase relationship between si(t) and its delayed replica, and the sign of sd(t) is of the same form as d(t), the original digital bit sequence can be determined by sampling to decide the sign of the detector output. Figure illustrates an example sequence of message binary digits, modulator wave- forms in DPSK, and phase and polarity relationships as applied to DPSK message recovery.
Q. In a GLC parallel circuit excited by a current source i(t), for G = 0.5S, L = 3H, and C = 0.5 F, determine i(t) if the inductor current iL(t) = 12e -0.5t .
NAND Gate NAND means NOT AND it complements the output of an AND gate. The symbol of NAND by a NOT gate. Generally Not operation is represented by a bubble as shown
Q. Briefly explain about Laplace transform? Many commonly encountered excitations can be represented by exponential functions. The differential equations describing the network
Q. How is the electron beam focused to a fine spot on the face of the CRT? Sol. The functional diagram of an electrostatic focusing arrangement is shown below. The pre-accele
Explain Einstein relation. Einstein relation: There exists a significant relation between the diffusion constant and the mobility. It is termed as the Einstein relation and
Balanced Score Card and Key Performance Indicators Every successful organization measures its performance across the subsequent parameters, for dissemination to all stakeholde
Mechanical Structure of Depletion Type MOSFET The mechanical structure of this type of device is displayed in figure. In an IC, we would locate two n-type regions side by side
Consider the magnetic circuit of Figure with an air gap, while neglecting leakage flux. Correct for fringing by adding the length of the air gap l g = 0.1 mm to each of the other
What makes them sine? Ans) Fourier tells that only a sine wave has no harmonic content. The math works out that if you have any wave shape other than a sign wave, you can brea
Q. Basic aspects of electromechanical energy converters? Whereas detailed differences and particularly challenging problems emerge among various machine types, this section bri
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