Complex filters used in analog domain [closed]

1. What are filters in analog circuits?
2. What are analog RC filters?
3. Why do we have analog filters and not just filter signals in the digital domain?

What are filters in analog circuits?

What Is a Filter? A filter is a circuit capable of passing (or amplifying) certain frequencies while attenuating other frequencies. Thus, a filter can extract important frequencies from signals that also contain undesirable or irrelevant frequencies.

What are analog RC filters?

Analog filters, such as the RC low-pass filter, always transition gradually from passband to stopband. This means that it is impossible to identify one frequency at which the filter stops passing signals and starts blocking signals.

Why do we have analog filters and not just filter signals in the digital domain?

Digital and analog filters both take out unwanted noise or signal components, but filters work differently in the analog and digital domains. Analog filters will remove everything above or below a chosen cutoff frequency, whereas digital filters can be more precisely programmed.