Explain amplitude-shift keying, Electrical Engineering

Assignment Help:

Q. Explain Amplitude-shift keying?

A carrier's amplitude is keyed between two levels (binary 1 and 0) in binary ASK. Figure shows the functions of a coherent ASK communication system. Let us consider a bit interval from 

1785_Explain Amplitude-shift keying.png


t = 0 to t = Tb, since the operation of any other interval will be similar. The desired ASK signal is given by

48_Explain Amplitude-shift keying1.png

where Ac, ωc, and φc are the peak amplitude, angular frequency, and phase angle of the modulated carrier, respectively. Equation can be viewed as a carrier Ac cos(ωct + φc) modulated by a digital signal d(t) that is 0 or 1 in a given bit interval. The digital signal and product device shown in Figure are then equivalent to the waveform formatter and modulator. Assuming that the received signal sR(t) differs only in amplitude from sASK(t), one can write

252_Explain Amplitude-shift keying2.png

The product device in the receiver's demodulator acts like a synchronous detector that removes the input carrier. The major disadvantage of the coherent ASK is that the required local carrier must be phase-connected with the input signal. The input to the integrator is a unipolar PCM signal, and the remainder of Figure is a PCM receiver.

The noncoherent ASK system eliminates the need for a coherent local oscillator. Figure shows the demodulator and code generator for a noncoherent ASK system. A matched filter (that has its impulse response matched to have the same form as the carrier pulse at its input) and envelope detector take the place of the synchronous detector and integrator of Figure.  While ASK systems are not as widely used as other systems for various reasons, the ASK concept remains significant, particularly as applied to modern optical communication systems which use intensity modulation of a light source.

154_Explain Amplitude-shift keying3.png


Related Discussions:- Explain amplitude-shift keying

Explain working of biased clamper, Q. Explain working of Biased Clamper? ...

Q. Explain working of Biased Clamper? Biased Clamper : The circuit of a positively biased clamper is shown in the figure. During the negative half cycle of the input signal the

Clc filter, CLC or π Filter The above diagram displays CLC or π ty...

CLC or π Filter The above diagram displays CLC or π type filter, which mainly contains a capacitor filter, followed through LC section. This filter offers a quite smooth o

Write a short note on rs-232-c, Write a short note on RS-232-C. The RS-...

Write a short note on RS-232-C. The RS-232 standard is a collection of connection standards among different pieces of equipment. The EIA RS-232 serial communication standard is

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

Synchronous motor, Q. A synchronous motor operates continuously on the foll...

Q. A synchronous motor operates continuously on the following duty cycle: 50 hp for 8 min, 100 hp for 8 min, 150 hp for 10 min, 120 hp for 20 min, and no load for 14min. Specify th

Working of crt, Q.   Explain working of CRT with suitable diagram discuss t...

Q.   Explain working of CRT with suitable diagram discuss the focusing arrangement. What is need of aquadag? OR Why are the operating voltages of a cathode ray tube arran

Hall effect - semiconductor, Explain hall affect and derive the mathematic...

Explain hall affect and derive the mathematical expression for hall coefficient, also describe its applications. Sol. Hall effect If a metal or semiconductor material carr

Find the corresponding energy, Q. Consider a pair of coupled coils as shown...

Q. Consider a pair of coupled coils as shown in Figure of the text, with currents, voltages, and polarity dots as indicated. Show that the mutual inductance is L 12 = L 21 = M by

What is the advantage of using jfet as an amplifier, Q. What is the advanta...

Q. What is the advantage of using JFET as an amplifier? As an amplifier of small time-varying signals, the JFET has a number of valuable assets. First of all it has a very high

Marginal tax rate, Stratos Corporation is a privately held tablet semicondu...

Stratos Corporation is a privately held tablet semiconductor technology firm with bright growth prospects.The past 5 years have seen the firm evolve from a pure startup to a profit

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