Illustrate differential phase-shift keying, Electrical Engineering

Assignment Help:

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.

870_Differential phase-shift keying.png

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.


Related Discussions:- Illustrate differential phase-shift keying

Decimal to binary conversion, Decimal  to binary Conversion To conver...

Decimal  to binary Conversion To convert a decimal  number to binary  any one  of the followings  two methods  can be used. Methods1 : This  is very common  methods of co

Line diagrams of a network-large company, i need a line diagram sample of a...

i need a line diagram sample of a large network, i need to practice how to draw and design such network

Discuss need of pipelining, Discuss need of Pipelining. The simplest m...

Discuss need of Pipelining. The simplest method for improving performance by hardware parallelism is pipelining. Pipelining has breaking up the operations to be performed in s

Basis of the electric solenoid actuator, There is a force on the plunger re...

There is a force on the plunger required to do to move it into or out of the gap and work must be done by or against this force. The conservation of energy dictates that the change

Find the overall current drawn from the supply, Q. A single-phase industria...

Q. A single-phase industrial plant consists of two loads in parallel: P1 = 48kW PF1 = 0.60 lagging P2 = 24kW PF2 = 0.96 leading It is operated from a 500-V, 60-Hz source.

What are concentrators, Q. What are concentrators? Elucidate how it helps i...

Q. What are concentrators? Elucidate how it helps in connecting number of subscribers. Ans: In rural areas, subscribers are usually dispersed. It is both expensive and unn

Distinguish between paramagnetic and diamagnetic materials, Distinguish bet...

Distinguish between paramagnetic and diamagnetic materials, mentioning at least one example of each. Paramagnetic Materials: The atoms of these materials have permanent magne

3-phase 3 wire meter, 3-Phase 3 Wire Meter A 3-phase 3 wire meter has ...

3-Phase 3 Wire Meter A 3-phase 3 wire meter has 2 elements of each category on the other hand of 3 elements as in the case of 3-phase 4 wire meter. The primary principle of op

Calculate the frequencies at which there is an alias, A pure sine wave alon...

A pure sine wave along with a frequency of 100Hz is sampled at 150Hz. At which point one of the subsequent frequencies would you expect an alias? A) 75Hz B) 100Hz C) 150Hz

Determine the output waveform of the voltage, Q. The first four harmonics i...

Q. The first four harmonics in the Fourier series of current waveform given by where I m = 15 mA and T = 1 ms. If such a current is applied to a parallel combination of R

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