What is the function of a high-pass filter?

A high-pass filter serves the specific function of allowing frequencies above a designated threshold to pass while attenuating frequencies that are lower than that threshold. This characteristic makes high-pass filters essential in various applications, such as audio processing, where they can help eliminate unwanted low-frequency noise and improve clarity in sounds, particularly in vocal signals or musical instruments.

The fundamental principle of a high-pass filter is based on its frequency response curve, which shows that as the frequency increases beyond the cutoff point, the output level increases, while frequencies below this point are progressively reduced. This behavior is crucial for tasks such as removing hum from audio signals or isolating high-frequency components in a signal processing chain.

In contrast, other choices do not accurately represent the function of high-pass filters. For instance, amplifying sound at low frequencies is the opposite of what a high-pass filter does, as it specifically blocks those lower frequencies. Similarly, while it may seem that attenuating all frequencies could describe a filter, a high-pass filter only attenuates those below a certain threshold, not all frequencies. Combining various frequency signals is also irrelevant to the function of a high-pass filter, which focuses solely on allowing high frequencies to pass. Thus, the correct choice is aptly identified as the one