Question

Problem 3 For the following signals, 345 points were sampled. a) 3.75 Hz signal sampled at 10 Hz b) 24.8 Hz signal sampled at 20 Hz c) 175 Hz signal sampled at 30 Hz Determine: i) The Nyquist frequency and whether the signal is aliased. ii) The values for Af and the uncertainty in the frequency ur (round to the nearest 0.001 Hz). If aliased, what is the aliased frequency (include a marked-up folding diagram, available on Canvas for Quiz 2 equations, if you use the folding diagram method). Find the peak frequency value obtained from a discrete Fourier transform (DFT) for each of these signals (Round your answer to the nearest 0.001 Hz). Hint: The possible discrete frequencies steps available from a DFT are n Af where n is a whole number (including 0). The nearest Δ step to the expected frequency has the highest peak amplitude on a DFT (where the expected frequency is either the actual signal frequency if it is unaliased or its aliased frequency). iii) iv)

Answer 1

Alan e allase Sampl ưng equo"Y 2 &bre.th The Nyquist -fhe 41,6

1t) The frequne 220 39.5

- 175 H2 OmpUin umber o 0 34「