4. (20 points) A spoken-word narration recorded on a book-on-CD is bandlimited to B 4 kHz. The narration is sampled at the standard rate of 44,100 samples/sec. To reconstruct it, the sampled narration is passed through a Butterworth low-pass filter with a cutoff frequency of f 4 kHz. What is the minimum filter order required so that all parts of the sampled signal spectrum, in the region IfI 2 f B, are suppressed by at least 0.001 times their unfiltered values? Hint: lHƯ)l = 1N1 + (f/h)2n. 4. (20 points) A spoken-word narration recorded on a book-on-CD is bandlimited to B 4 kHz. The narration is sampled at the standard rate of 44,100 samples/sec. To reconstruct it, the sampled narration is passed through a Butterworth low-pass filter with a cutoff frequency of f 4 kHz. What is the minimum filter order required so that all parts of the sampled signal spectrum, in the region IfI 2 f B, are suppressed by at least 0.001 times their unfiltered values? Hint: lHƯ)l = 1N1 + (f/h)2n.
-
Engineering 2022-05-15 19:04:59