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Exercises 1.) Use dsolve to obtain a symbolic expression for the zero-input response for the following system: y”’+8y”+2521y’+5018y=f”+5018f, y(0)=1 ,y'(0)=1,y”(0)=0 2.) Plot the zero-input response for the system from part 1 with 0 ≤ t ≤ 4. 3.) Create a system object using tf ...
Problem 6 Consider a superheterodyne receiver for standard AM radio. a. If you wish to receive a radio station at 1345 𝑘𝐻𝑧, what local oscillator frequency is needed? (Let 𝑓𝐼𝐹=255 𝑘𝐻𝑧) b. What is the “image station” we need to watch out for ...
4 Problem 5 Answer the questions a. Briefly show the advantages and disadvantages of DSB-LC. b. Briefly show the advantages of DSB-SC compared to DSB-LC. c. Briefly explain the advantages of using QAM. Is QAM always better than DSB-SC?
Problem 4 Consider a message signal 𝑚(𝑡) with bandwidth 𝑊=2 𝑘𝐻𝑧, applied to a DSB-SC modulator, s.t., 𝑠(𝑡)=𝐴𝑐𝑚(𝑡)cos(2𝜋𝑓𝑐𝑡). Assuming perfect synchronism between the carrier waves in the modulator and detector. a. Determine (sketch) the spectrum of the detector output when 𝑓𝑐=1 ...
Consider a message signal 𝑚(𝑡)=cos(4𝜋𝑡)volts(1𝛺), and carrier 𝑐(𝑡)=cos(20𝜋𝑡) 𝑉(1Ω). Assuming 𝑥(𝑡)=[3𝑚(𝑡)+5]𝑐(𝑡), (DSB-LC). a. What is the modulation index? b. Find the closed form of 𝑋(𝑓), c. Sketch 𝑋(𝑓) d. Find the power developed across a load of 75 ohm due to this AM wave. e. ...
Problem 2 Find the energy spectral density (ESD), 𝑆𝑋(𝑓), of 𝑠(𝑡)=e^5𝑡𝑢(−𝑡).