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# Electrical Engineering

### Calculate the Per-Unit Current and Load Current in Amperes

Three zones of a single-phase circuit are identified in figure 3.10(a) {see the attachment}. The zones are connected by two transformers, T1 and T1, whose ratings are also shown in the same figure. Using the base values 20 kVa and 115 volts in zone-3, calculate the per-unit current and load current in amperes. Neglect the transf

### Calculate the Per-Unit Source Voltages

Three zones of a single-phase circuit are identified in the attached figure 3.10(a) {see attachment}. The zones are connected by two transformers, T1 and T1, whose ratings are also shown in the same figure. Using the base values 20 kVa and 115 volts in zone 3, calculate the per-unit source voltage. Neglect the transformer windi

### Calculating Line Voltage at the Load

Two balanced, in parallel connected, three-phase loads are fed by a three-phase line with an impedance of (2+j4) Ohm per phase. Calculate the line voltage at the load, given the phase voltage and per-phase current. Please see the attached file for the four possible options and the adequate notation of the formulas.

A three-phase overhead transmission line has a per-phase resistance of 0.15 ohm/km, and a per-phase inductance of 1.3263 mH/km. Assume that the shunt capacitance is negligible. The length of the line is 40 kilometers and it operates under 220 kV and 60-Hz. The line is supplying a three-phase load of 381 MVA at 0.8 power factor l

Two balanced, in parallel connected, three phase loads are fed by a three phase line with a certain impedance per phase. Parameters are given for each load, with the line energized at the sending end from a 60Hz, three-phase balanced voltage source with line to line voltage of 120*((3)^(1/2))*(V) rms. Given the phase voltage (

### Network Planning, Link Budget, and Hata Model

A Potential client has asked you to predict the number of cells necessary to cover 100 square miles. The area the client wished to cover compromises 5 sq miles Urban, 25 sq miles, Suburban and the remainder rural. For urban areas the client can acquire 30 m towers, for Suburban 60 m and for rural 100 m Assume feeder lengths =

### Communications Systems of Frequency Downconverters

A frequency downconverter is implemented using a square-law device as follows. The band-pass filter has a center frequency fi=|fc - ft| (also known as the intermediate frequency, IF). Assume that the message bandwidth of the input signal m(t) is equal to B Hz. a) Determine the smallest possible IF frequency, so that there

### Wireless Communication

1. For an urban environment, at 1900MHz, what is the path loss between a base station at 40m height and a mobile at 1.6m height separated by a distance of 5 km? 2. TDMA has 416 frequencies in one of the cellular license bands. If a cellular operator designs a network with a 5/15 reuse pattern, how many frequencies per cell

### Wireless Communication Systems

1. Assume a CDMA system has only 4 walsh codes. If the mobile is assigned W4 and receives a data stream of 11011010, what is the output? 2. What is the c/I for a network using a 7/21 reuse pattern? (consider only the closest 6 interferers and a propagation exponent of 3.5)

### Root Locus and Root Locus Design

Please help me with the attached root locus design question (see attachment). (Involves: plotting the root locus, determining gain, designing a proportional and integral controller, determining the location of the controller zero, and finding the required controller gain).

### Linear System Stability - Bode, Nyquist, Root Locus

Please answer the attached questions regarding linear system stability. (Involves: loop transfer function; Bode plot; Nyquist diagram; gain, phase and robust stability margins; positive gain root locus).

### C++ Program - Min/Max Number

I started writing a program and need help. I need to be able to enter up to 15 numbers and output the minimum number, maximum number and the geometric mean. I have a program started, is there a way to shorten it? And I don't understand the geometric mean. Thank you for your help.

### C++ Program Help

I am trying to make a program that will read a file from a disk and will take the first letter of each word and and make that into a sentence. Example: Can Always Talk == CAT I can get into the file, just can't make it work.

### Fault Currents and Three Phase Faults

Please see the attached diagram for the specific parameters in finding the real, sub-transient fault current for a line to ground fault. The same process should be repeated in finding the three phase fault at the same point.

### Programming Logic for Movie Collection

You want to produce a report of your movie collection. Which fields would you use, and which would be the data types of each of those fields? Create a flowchart and pseudo-code for generating a report that prints all of the movies, with all movies made by the same director on one page, as well as the number of movies by each

### DSP

[A] The frequency response of a 2nd order LTI filter is H(e^jw)=(b0+b1e^-jw+b2*e^-2jw)/(1-a1*e^-jw-a2*e^-2jw) Assume b1=b2=0. In each case state whether the filter is highpass, lowpass or band pass and draw the pole/zero plot. i) a1=-1.8, a2=-.81 ii) a1=-1.27, a2=-.81 iii) a1=0,a2=-.81 iv) a1=1.27,a2=-.81 Explain th

### First Order Controller Design

Given P = [(3e)^-10.03s] / [s/4 + 1], use the Inverse Nichols Chart to design a simple G(s) to achieve the following specifications. i) Zero steady state error to a step output disturbance. ii) |1/(1 + L)| <= -15dB, w <= 1 rad/s. iii) [1/(1 + L)| <= 3dB, Aw. See the attached files.

### Feedback Control Systems and Block Diagram Algebra

1. Explain why high loop gain results in "good" tracking and disturbance rejection 2. Use block diagram reduction to find the transfer function from R1 to Y1 for the following system. (You can take all other external inputs to be zero). See the attached file.

### Closed Loop System Transfer Function

Consider a control system described by the attached state space model. (1) For the system in question do the following: - Find the system transfer function, {see attachment} - Find the system eigenvalues - Check the system controllability and observability (2) Assume the state feedback of the form: {see attachment} and

### Wireless Communication and Walsh Code Matrix

(a) Graph the theoretical number of users of a CDMA system with a data rate of 9.6 kbs and 14.4 kbs while varying the Voice activity factors from 10% - 100% (b) Create the Walsh code matrix for a W16. (c) For IS-95, on the forward link, list the Walsh code assigned to the various logical channels (hint: there are 64 Walsh code

### Capacitance with Permittivity (Laplace's Equation)

A parallel plate capacitor has its plates at x = o and x = d. The space between the plates is filled with an inhomogenous material with permittivity: {see attachment}. The plate at x = d is maintained at Vo while the plate at x = o is grounded. (a) Solve Laplace's Equation for V(x) (b) Find the field {see attachment} between

### Matlab: Rectangular Window or Von Hann (Hanning) Window

Assume the signal consist of a sum of 3 sinusoids (sine functions, no phase delay). One sine is at 50hz, the second is at 60hz, and the third is at 75 Hz. The 50hz and 60hz sines have a peak magnitude of 1, the 75hz sine has a peak magnitude of .1. Assume the combined signal is sampled at 240hz, and 256 samples of the signal are

### Transfer Function and Feedback Control System

An open loop transfer function of a certain unit feedback control system is described as below, where K is an adjustable gain (Proportional Controller) and G(s) is a process transfer function. 1. In the space provided (see attached), sketch a Root Locus plot of the closed loop system for positive Proportional Controller gain

### Proportional-Rate Feedback Control System

Consider the block diagram in Figure Q3.1, describing the process from Question 2, under Proportional-Rate Feedback control (see attached). 1. Find a closed loop system transfer function in terms of controller gains, Kp, Kd. 2. Find the values of gains Kp, Kd such that the resulting Percent Overshoot of the closed loop s

### Control Systems with Complex Poles

Consider five different control systems, with descriptions below. Which system will have the slowest rise time? (see attached) System 1: Two complex poles at -10 -j5, -10 +j5; System 2: Two complex poles at -10 -j5, -10 +j5 and a zero at +2; System 3: Two real poles at -10, -3; System 4: Two complex poles at: -10 -j5, -10

### Communications Systems

Please refer to the attached file. It may contain more than one-page. A PCM system with uniform quantization is used to transmit a speech signal. The bandwidth of the signal is equal to 6 KHz. At the receiver we require an SNR in the reconstructed signal equal to 40 dB. a) What is the minimum sampling rate for the speech

### Transistor Saturation

For the circuit of the figure attached, determine the required values of Rd, R1 and R2 so that the transistor operates in the saturation region with Id=0.5mA and Vd=3V. The enhancement mode PMOS transistor has Vt=-1V and K=0.5mAV^-2. What is the largest value Rd can have while maintaining the transistor in saturation?

### Bipolar Junction Transistor

A silicon n-p-n bipolar junction transistor is designed with emitter, base and collector doping levels of 10^19cm, 10^15cm and 5*10^17cm, respectively. Assuming the intrinsic carrier concentration (ni) in silicon to be 10^10cm, calculate the Fermi Energy, Ef, relative to the intrinsic energy scale clearly to show the relative po

### Block Diagram Reduction

First Problem: 1. Find TY/R. 2. Find TU/d Second Problem: a) Find TY/R for the following system.