DED

If the Signal to Noise Ratio (SNR) of a wireless link is 20DB and the Radio Frequency(RF) bandwidth is 20kHz, using Shannon's capacity formula, determine the maximum theoretical data rate that can be transmitted.(5 marks) b)With the aid of block diagrams explain the principle operation of (DSSS) Direct Sequence Spread Spectrum and (FHSS) Frequency Hopping Spread Spectrum transmission techniques.(12 marks) With the aid of a diagram and a brief explanation, what is the purpose of the autocorrelation function, and how does it work in a DSSS WLAN.(8 marks)

(a) A 50 m long lossless transmission line with Zo = 50 ohms operating at 50 MHz is terminated with a load ZL = 90 + j 30 ohms. If the wave velocity is u =0.8 c,where cis the speed of light in vacuum, find: i. The reflection coefficient ii. The input impedance (b) The Direct Broadcast System (DBS) satellite (at a distance of 39000 km)transmits at 13 GHz in the Ku Band, with a transmit power of 200 W, with a transmit antenna gain of 35 dB and with an IF (Intermediate Frequency)bandwidth of 30 MHz. The ground receiving station dish has a gain of 32 d Band sees an average background brightness temperature of Tb = 50 K. The receiver LNB (Low Noise Block) has a noise figure of 1.8 dB. Find: i.The EIRP (Effective Isotropic Radiated Power) ii.The power received at the input of the LNB iii.The signal to Noise ratio at the LNB output iv.Comment on what would happen if both transmit and receive antennas are replaced by typical monopole antennas. (c) A certain two-port network is measured and the following scattering matrix is obtained: [S]=\left[\begin{array}{cc} 0.3 \angle 0^{\circ} & 0.7 \angle 90^{\circ} \\ 0.7 \angle 90^{\circ} & 0.3 \angle 0^{\circ} \end{array}\right] From the data determine: i.If the network is reciprocal ii.If the network is lossless (d) Briefly describe how the following RF systems operate: i.Wilkinson power divider ii.Circulator

Problem 2. (15 points) Design the lead compensator such that you can achieve the both requirements. D_{c}(s)=\frac{T_{d} s+1}{\alpha T_{d} s+1} where a < 1. Use K you designed in Prob. 1. Provide the Bode plot of the open-loop with the stability margins. You will need iterations to find the correct max and max

Problem 3. (15 points) Design the lag compensator such that you achieve the both re-requirements. D_{c}(s)=\frac{T_{i} s+1}{\alpha T_{i} s+1} where a > 1. Use K you designed in Prob. 1. Provide the Bode plot of the open-loop with the stability margins. You will need iterations to find the correct T; and a.

Consider the closed-loop control system shown below: \text { where } C(s)=K D_{c}(s) \text { and } G(s)=\frac{1}{(s+1)\left(\frac{s}{2}+1\right)\left(\frac{s}{5}+1\right)} The design requirements are given below: \text { 1. Stcady-state requircment: } K_{p} \geq 9 \text { ( } K_{p} \text { is a static position crror constant.) } 2. Transient requirement: phase margin > 45 deg Problem 1. (10 points) Assuming De(s) = 1, dctcrminc K such that you can achicve thesteady-state requirement. Then, provide the Bode plot of the open-loop with the stabilitymargins (use "margin" command in MATLAB).

At 50m you receive a -60 dBmW signal, at a frequency of 5GHZ. What was thetransmitted power in Watts if you ignore antenna gain and any losses.Please show all your working.(a)(10 marks) (b)A data transmission line has the following characteristics: Characteristic impedance: 50N Сараcitance: 100pF/m Attenuation (per 100m):1 1. The inductance per metre of the line 2. The attenuation coefficient at 10MHZ 3. The phase delay in degrees between two points over 5 metres at a frequency of10MHZ(6 marks)

Electro Magnetic Interference (EMI) is normally considered as being either conductive or radiative. For each type of interference describe ways of reducing their effects. A carrier of frequency 800kHz is being Amplitude Modulated (AM) by a modulating signal that is a sine wave at a constant frequency of 8kHz and constant amplitude. The modulation index is less than 100%. Determine the frequency of the upper sideband and lower sideband and total bandwidth of the resultant Amplitude Modulated(3 marks)waveform. If the carrier in part (b) has a peak-to-peak voltage of 10V and the modulating signal has a peak-to-peak voltage of 5V, determine the modulation index, the maximum and minimum voltages of the resultant Amplitude Modulated waveform and the peak amplitude of the upper and lower side bands. Hence, determine the modulating signal voltage that would result in 100% modulation.(7 marks) Briefly describe the process by which the modulating signal would be extracted from the Amplitude Modulated waveform at a receiver. Using the signal described in part(b) and if the demodulator comprises a simple diode detector, determine a value for the demodulator's time constant and justify your choice. Hence, determine the value of capacitance required if the resistance = 2k.(9 marks)

3. Use the "Sommerfeld ground" option in FEKO and choose some specific values of the parameters for the lossy ground. You can use a value for the conductivity 10-03 ≤ ≤ 12 × 10-03 Siemens/meter, and, the relative permittivity as & = 15; the permeability is Mo = 4π X 10-07 Henries/meter. (These are the data one needs to enter when using the Sommerfeld ground option in FEKO.) Repeat the results of part 1 using the lossy ground option and compare your results in part 3 against the ones obtained in parts 1 and 2.

1- When a cable carries multiple currents, all in the same direction, this would be associated with which coupling mode? Select one: A. Differential mode B. Common mode C. Antenna mode D. Common impedance E. None of the above 2- Interference at the source can be reduced by: Select one: A. Low noise design B. Shielding C. Decoupling D. Filtering E. All of the above 3- Shielding for magnetic fields at low frequency can be done with: Select one: A. Purely conductive material B. Aluminium C. Copper D. A high-permeability material such as mu-metal or its derivatives E. B & C 4- In hazardous areas, one would be more inclined to consider Select one: A. both the upper and lower explosive limit B. the lower explosive limit C. the upper explosive limit D the upper flammable limit 5- An instrument is to be mounted in a hazardous area. If it is marked T2" (maximum surface temperature of 300°C). Select one: A. it is safe to be used with gasses and vapours that have an ignition temperature greater than 300°C. B. it is safe to be used with gasses and vapours that have an ignition temperature lower that 300°C. C it can only be used with gasses and vapours whose ignition temperature is 300°C. D. it is unsafe as it gets too hot 6- ATEX 100a European Directive deals solely with Select one: A. the minimum requirements for improving the safety and health protection of workers potentially at risk from an explosive atmosphere B. the zone classification of a hazardous area C equipment and protective systems intended for use in potentially explosive atmospheres D. the IEC Standard to which equipment is certified 7- Who, generally speaking, is held responsible for the appropriate explosion protection safety of any given installation? Select one: A. The installer B. The equipment supplier C. The certifying authority D. The plant owner 8- HAZOPS work best if they are conducted Select one: A. when the P&IDs have been finalised, but before detailed design has commenced B. at any time. They are not influenced by P&IDs C. over beer and pretzels D. before the P&IDs have started 9- Which of the following listed certificate numbers would be for an equipment which has special conditions for installation of operation? Select one: A. BASOSATEX1234 U B. PTB07ATEX1784X C. SIRA09ATEX0645/1 D. CESI08ATEX1323

Objectives: Set up antenna experiment, analyze/interpret data, and use engineering judgment to draw conclusions. Report effectively with a range of audiences. A B RG-39-7 2 D Figure 1. An example coaxial cable is shown. 'A' denotes the outer insulator. 'B' denotes the outer conductor. 'C' denotes the inner insulator. 'D' denotes the inner conductor. Lab 6 Instructions: a) Investigate using a coaxial cable to create a center-fed half-wavelength dipole antenna with a length of about 2.45 inches (i.e. dipole length). Assume the coaxial cable has an SMA connectors. b) Write a report for Lab6. A sample Lab6 report outline is below: 1. Introduction/Team Members/Team Members Contribution Paragraph(s) should introduce the laboratory, team member names, contributions of each team member, etc. (If a member doesn't contribute, then simply list their contribution as none. You will not lose points for the other team members lack of contributions.) II. Block Diagram Sketch of Experiment Create a block diagram(s) or sketch(s) as described below. Include a figure caption(s), annotations, etc. for your block diagram(s). A. Create sketches illustrating the assemble/build steps for a design of center-fed half-wavelength dipole antenna with a length of about 2.45 inches (i.e. dipole length). B. Sketch the current distribution for a center-fed half-wavelength dipole antenna. III. Data Analysis and Interpretation A. Calculate the length in cm of your center-fed half-wavelength dipole antenna design. B. Calculate the free-space frequency corresponding to a wavelength of 4.90 inches. C. Discuss bandwidth of your center-fed half-wavelength dipole antenna design. IV. Conclusions Paragraph(s) summarizing what you learned/discovered in the lab experience. Considering the concepts learned during this course, draw conclusions. c) Create a file (i.e. pdf, doc, or docx) of your Lab6 report. Each student creates their own Lab6 report. d) In Canvas, upload your Lab6 report (i.e. pdf, doc, or docx) to LAB6 (See Tab -> Canvas Assignments) by its Canvas due date.