savage67
Member level 1
Dear friends, the question below asked in my latest signal processing exam. I have no idea about it and i could not find any solution in literature. Could you please help me finding out the answer. Actually i believe that i am quite good at signal processing until this question.
A voltage signal is sampled digitally in the laboratory at three different sampling frequencies, and FFTs are performed on the sampled data. In all cases, 512 data points are taken. Here is a record of the observations:
‒ Data sampled at 115 Hz: A peak appears in the frequency spectrum at 2 Hz, with amplitude close to 3.0 V. Another peak appears in the frequency spectrum at 45 Hz, with amplitude close to 1.0 V.
‒ Data sampled at 280 Hz: A peak appears in the frequency spectrum at 48 Hz, with amplitude close to 3.0 V. Another peak appears in the frequency spectrum at 95 Hz, with amplitude close to 1.0 V.
Question: What are most likely the true frequencies (and their corresponding amplitudes) in the voltage signal.
A voltage signal is sampled digitally in the laboratory at three different sampling frequencies, and FFTs are performed on the sampled data. In all cases, 512 data points are taken. Here is a record of the observations:
‒ Data sampled at 115 Hz: A peak appears in the frequency spectrum at 2 Hz, with amplitude close to 3.0 V. Another peak appears in the frequency spectrum at 45 Hz, with amplitude close to 1.0 V.
‒ Data sampled at 280 Hz: A peak appears in the frequency spectrum at 48 Hz, with amplitude close to 3.0 V. Another peak appears in the frequency spectrum at 95 Hz, with amplitude close to 1.0 V.
Question: What are most likely the true frequencies (and their corresponding amplitudes) in the voltage signal.