1 a mn t cos 2 fc t with fc the effective

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Unformatted text preview: fc t + θ ) and sin ( 2π fc t + θ ) . Show how to use these oscillator signals plus two lowpass filters to build a receiver that recovers both message signals from x (t ) . c) Now suppose that the local oscillator in your receiver design from part (b) has a phase error, so the oscillator signals are actually cos ( 2π fc t + φ ) and sin ( 2π fc t + φ ) where φ ≠ θ . Find the output signals produced by your receiver. Why is this case worse than what happens with phase error in DSB- SC? 4. Suppose that mn (t ) is the triangular wave message signal shown below. !1 + a mn (t )# cos ( 2π fc t + θ ) (with fc >> the effective a) The AM wave x (t ) = A " $ bandwidth of mn (t ) ) is applied to an ideal envelope detector, which produces the output y (t ) shown on the next page. What are the values of A and a ? b) Now suppose that the value of a is increased to 1.5. Sketch the envelope detector output. 5. (This is a...
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This homework help was uploaded on 03/06/2014 for the course ECE 563 taught by Professor Goeckel during the Fall '11 term at UMass (Amherst).

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