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formula,: we have from DTFT of y[n]Note the above expression is two pulses at and the scaling factor is:where Therefore, where (b) ans: After the ideal LPF, the Fourier transform of Take inverse Fourier transform of , the output signal is:Note both the and θ terms are introduced by ZOH function where is introduced because is nonideal and θ represents the delay of Q . We want to digitize and store a signal on a CD, and then reconstruct it at a later time. Let the signal and let the sampling frequency Hz.(a) Determine the continuous time signal after the reconstruction.(a) ans: Assuming (ZOH+ ideal LPF) is used. This problem can be solved by using the results directly from . In there are 3 sinusoidal signals instead of only one in . Details of the solutions are omitted.