In a digital filter, what does "feedback" refer to?

A) Using previous output values to compute the current output

B) Sampling the input signal multiple times

C) Increasing the filter's bandwidth

D) Enhancing the input signal

Answer: A) Using previous output values to compute the current output

Explanation: Feedback in a digital filter refers to using previous output values in the computation of the current output, which is a characteristic of IIR filters. This allows for a more complex response to input signals.