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Question and answers about analog communication
Typology: Thesis
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University of Akron Department of Electrical and Computer Engineering 4400 341: Introduction to Communication Systems - Spring 2015 Assignment โ 3 3.8- 4 Find the mean square value (or power) of the output voltage y(t) of the system shown in Figure 1 if the input voltage PSD ๐! ๐ = ฮ (๐๐). Calculate the power (mean square value) of the input signal x(t). Figure 1
4.2- 1 You are given the baseband signals: I. ๐ ๐ก = cos( 1000 ๐๐ก) II. ๐ ๐ก = 2cos 1000 ๐๐ก + sin( 2000 ๐๐ก) III. ๐ ๐ก = cos( 1000 ๐๐ก) cos( 3000 ๐๐ก) IV. exp (โ 10 ๐ก ) For each one, do the following: a) Sketch the spectrum of m(t) b) Sketch the spectrum of the DSB-SC signal m(t)cos( 10 , 000 ๐๐ก) c) Identify the upper sideband (USB) and lower sideband (LSB) spectra.
4.2- 8 The system shown in Figure 2 is used for scrambling audio signals. The output y(t) is the scrambled version of the input m(t). a) Find the spectrum of the scrambled signal y(t) b) Suggest a method of descrambling y(t) to obtain m(t) Figure 2
4.3- 5 In a DSB-SC amplitude modulation system, the message signal is ๐ ๐ก = ๐!!!๐ข(๐ก โ 2 ) and the carrier signal is cos( 2000 ๐๐ก). a) Find and sketch the Fourier transform of the message signal. b) Find and sketch the Fourier transform of the modulated signal.
