What is the most appropriate sampling rate for a HFF setting of 70 Hz, according to Nyquist theory?

According to Nyquist theory, to accurately capture a signal, the sampling rate must be at least twice the highest frequency present in the signal. This is known as the Nyquist rate. In this scenario, the high-frequency filter (HFF) is set to 70 Hz. Therefore, to determine the appropriate sampling rate, you would multiply the HFF setting by two.

Thus, the minimum sampling rate required would be 70 Hz x 2, which equals 140 Hz. Sampling at this rate ensures that any signals with frequencies up to 70 Hz can be effectively sampled without aliasing, meaning that the original signal can be reconstructed accurately from its samples.

Choosing a sampling rate lower than this would result in loss of fidelity and potential distortion of the signal, while selecting a higher rate would not directly improve the representation of the signal beyond the necessary threshold but could be considered for improving resolution or accommodating factors like noise. Therefore, 140 samples per second is the correct answer, as it aligns perfectly with the Nyquist requirement for the specified HFF setting.