ECE 438 Assignment No. 3 Spring 2018 - Purdue Engineeringece438/hw_sol/hw3_sol.pdf · Since X_s(f)...

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ECE 438 Assignment No. 3 Spring 2018 f

Transcript of ECE 438 Assignment No. 3 Spring 2018 - Purdue Engineeringece438/hw_sol/hw3_sol.pdf · Since X_s(f)...

Page 1: ECE 438 Assignment No. 3 Spring 2018 - Purdue Engineeringece438/hw_sol/hw3_sol.pdf · Since X_s(f) == 1, X(\omega) == 1. This is consistent with the fact that x[n] = \delta[n], as

ECE 438 Assignment No. 3 Spring 2018

f

Page 2: ECE 438 Assignment No. 3 Spring 2018 - Purdue Engineeringece438/hw_sol/hw3_sol.pdf · Since X_s(f) == 1, X(\omega) == 1. This is consistent with the fact that x[n] = \delta[n], as

f

f

Note that sinc(20f) has zero crossings at f=k/20 for integer k.

An alternate answer for (c)-i is

𝑋𝑐(𝑓) = sin(2πf10) / sin(2𝜋𝑓2) ∙ {𝑠𝑖𝑛𝑐(2(𝑓 − 1/4)) + 𝑠𝑖𝑛𝑐(2(𝑓 + 1/4))}

Page 3: ECE 438 Assignment No. 3 Spring 2018 - Purdue Engineeringece438/hw_sol/hw3_sol.pdf · Since X_s(f) == 1, X(\omega) == 1. This is consistent with the fact that x[n] = \delta[n], as

-8 -6 -4 -2 0 2 4 6 8 n

x[n]

t

x(t)

1/800 2/800 3/800 4/800

Page 4: ECE 438 Assignment No. 3 Spring 2018 - Purdue Engineeringece438/hw_sol/hw3_sol.pdf · Since X_s(f) == 1, X(\omega) == 1. This is consistent with the fact that x[n] = \delta[n], as
allebach
Text Box
Since X_s(f) == 1, X(\omega) == 1. This is consistent with the fact that x[n] = \delta[n], as shown in part (a). So the solution below is not correct.
Page 5: ECE 438 Assignment No. 3 Spring 2018 - Purdue Engineeringece438/hw_sol/hw3_sol.pdf · Since X_s(f) == 1, X(\omega) == 1. This is consistent with the fact that x[n] = \delta[n], as
Page 6: ECE 438 Assignment No. 3 Spring 2018 - Purdue Engineeringece438/hw_sol/hw3_sol.pdf · Since X_s(f) == 1, X(\omega) == 1. This is consistent with the fact that x[n] = \delta[n], as
Page 7: ECE 438 Assignment No. 3 Spring 2018 - Purdue Engineeringece438/hw_sol/hw3_sol.pdf · Since X_s(f) == 1, X(\omega) == 1. This is consistent with the fact that x[n] = \delta[n], as
Page 8: ECE 438 Assignment No. 3 Spring 2018 - Purdue Engineeringece438/hw_sol/hw3_sol.pdf · Since X_s(f) == 1, X(\omega) == 1. This is consistent with the fact that x[n] = \delta[n], as
Page 9: ECE 438 Assignment No. 3 Spring 2018 - Purdue Engineeringece438/hw_sol/hw3_sol.pdf · Since X_s(f) == 1, X(\omega) == 1. This is consistent with the fact that x[n] = \delta[n], as
Page 10: ECE 438 Assignment No. 3 Spring 2018 - Purdue Engineeringece438/hw_sol/hw3_sol.pdf · Since X_s(f) == 1, X(\omega) == 1. This is consistent with the fact that x[n] = \delta[n], as