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# Electrical Engineering

### 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

### 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).

### 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

### 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

### 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

### 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

### Proportional-Rate Feedback Control

Consider the block diagram in the attached figure Q3.1, describing the process under Proportional-Rate Feedback control. 1) Find a closed loop system transfer function in terms of controller gains, Kp, Kd. 2) Find the value gains Kp,Kd such that the resulting Percent Overshoot of the closed loop step response will be equal

### Control Systems - Proportional-Integral-Derivative Controlled Process and Nyquist Plots

Consider the block diagram attached, describing a process under Proportional-Integral-Derivative control. 1) Is the system open loop stable? Justify your answer 2) Let Ki = 10. Use the Routh-Hurwitz criterion to find the range of Kd, and Kp in terms of Kd, so that closed loop stability is achieved. 3) Suppose that Ki =

### Control Systems - Unity Feedback Loop, Nyquist Contour, Routh-Hurwitz Analysis

A process has a transfer function: {see attached} and is included in a unity feedback loop with a proportional controller Kp in a feedforward branch of the control loop. (a) Sketch a Nyquist contour for this system (b) Apply the Nyquist stability criterion to find a suitable range of K for stable closed loop system behaviour.

In order to delimit messages from a stream of bits being exchanged on a data link, a sender marks the beginning and end of each message with a control flag. In order to prevent the receiver from inadvertently detecting the end of a message when a pattern in the data matches the control flag, the sender stuffs extra bits or chara

### Control Systems (Transfer Function; Open / Closed Loop System; Observable / Unobservable)

A system described in the attachment is under feedback control of the form u = Kx + r where r is the reference input. (i) Show that (A,C) is observable. (ii) Compute a K of the form {see attachment} so that (A - BK, C) is unobservable. (I.e., the closed loop system is unobservable) (iii) Find the transfer function of the open

### Block diagram in feedback control system form

I attached a Word document with a circuit: a) Draw a block diagram of the circuit in feedback control system form. b) Derive an expression for Io in terms of Vi and the system parameters Av, Ro, RL, and Rf. c) How should the system be designed to make Io independent of RL? What is the approximate expression for Io in terms

### Erlang Problem Described

1. A company needs to provide sufficient private trunks between two switches to accommodate 90% of call attempts among employees during the busy hour. Assume that there will be 560 callers at random times during that hour, and that call duration averages 3 minutes. Employees are instructed to attempt to call using a trunk; if bl

### System Under Feedback Control Transfer Functions

Consider the attached system under feedback control and answer the listed questions please.

### Input Tone in to an Amplifier

Consider a single input tone, such that: Vo = ko + k1*Vin + k2* Vin^2 + k3*Vin^3 +.... Let Vin = cos(wt). Now if a tone is put into an amplifier, and its amplitude is increased by 1.5dB, how much will the amplitude of the third order products increase in dB? Using the third order term only of the transfer polynomial, prove this

### Tones Input In To An Amplifier

Suppose two tones are input in to an amplifier. The tones are pure sinusoids with one at frequencies 8GHz and the other at frequency 8.03GHz,(delta f =0.03GHz). Assume that the transfer characteristic of the amplifier is represented by Vout= ko + k1Vin +k2Vin^2 +k3Vin^3...+k9Vin^9. List the output frequencies of all 3rd order (t

### PI (Proportional and Integral) Controller Design [Inverse Nichols Chart Used]

Given the plant, P(s) = {see attachment}, a proportional and integral (PI) controller, G(s) = {see attachment} is to be designed to achieve the following specifications ... *Please see attachment for complete question (including specifications)

### Root Locus for a Closed Loop System

Sketch the root locus for the following closed loop system {see attachment} as {SYMBOL1} varies from -{SYMBOL2} to +{SYMBOL2}. You should calculate all steps and show the positive and negative gain loci. It is recommended that you first find the positive locus and then sketch the negative {SYMBOL2} locus. (Real axis solutions o

### Two D-Type Flip-Flop Questions

Please help me solve the following problems. Problem 1: Consider the following circuit (see attached). IC 1 is a 3-bit asynchronous (ripple) counter, positive-edge triggered. At higher speeds propagation delay will affect the proper function of the counter so that the counting sequence is altered. Glitches will be produced

### Control Systems.

Please refer to the attached file. Consider the attached unity feedback system with plant transfer function... (attached)

### Inverse z Transformation

Use any method to determine the inverse z transform for the following function: X(z) = (z^3-2*z)/((z-2) - left sided sequence

### Complex Gaussian Noise

2.a) Using the result for P(I) in Question 1, prove that the n-th moment of complex Gaussian noise is {I^n} = n!(2sigma^2)^n You may use the following result for the Gamma integral Gamma(n-1) = n! = integral x^n exp(-x)dx. b) Hence, obtain an expression for the normalized moments {I^n}/{I}^n c) Deduce that the v

### VLSM Exercise

VLSM Exercise Details are : ---> VLSM Exercise: Site A 60 users Serial links Site B Site C Site D Site E 20 users 10 users 10 users 48 users You are given the 192.16.15.0 address. Effectively address all router interfaces using VLSM. Each side of the arrows is a serial interface. Each site has an Ethernet