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. A balanced delta-connected load with a per-phase impedance of 12 + j9 is supplied by a 173-V, 60-Hz three-phase source. (a) Determine the line current, the power factor, th
Components of PLC There are followings three main components of PLC : a.The power supply and rack. b.The central processing unit ( CPU) c.The input / output (I/O
1 diagram basic layout of a simple transformer
Q. Determine the voltages Vx using voltage division and equivalent resistor reductions for the circuits shown in Figure.
1. For the flyback converter operating in the discontinuous "current" (flux) mode, derive an expression for the time at which the magnetizing current returns to zero. 2. A forwa
Q. Describe binary number system? The binary number system has a base of 2 with two distinct digits (bits), 1 and 0. A binary number is expressed as a string of 0s and 1s, and
Mini Computers Larger computer more computing power having capability to address more memory and more speed than microcomputer called minicomputer. These computers
Consider the basic MOSFET circuit shown in Figure with variable gate voltage. The MOSFET is given to have very large V A , V T = 4V,and I DSS = 8 mA. Determine i D and v DS for
Q. Electronic Photo Flash? A simplified schematic diagram of the electric circuit of an electronic photo flash typically used on cameras is shown in Figure 7.7.1. By passing a
The distribution transformer is supplying a load at 240 V and 0.8 power factor lagging. The open-circuit and short-circuit test data are given in Example. (a) Determine the frac
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