A band-stop filter passes frequencies above and below a certain range.

An all-pass filter passes through all frequencies unchanged, but changes the phase of the signal.

A low-pass filter passes low frequencies while blocking higher frequencies.

A band-stop filter passes high and low frequencies outside of a specified band.

An all-pass filter passes all frequencies equally well, but alters the phase relationship among them.

A typical filter might pass frequencies over 4,000 Hz (4 kHz).

Cutoff frequency is the frequency beyond which the filter will not pass signals.

These optical filters usually have more exact reflective and pass bands than absorptive filters.

We then apply a specific filter which will allow only the desired signal to pass.

Each filter passes the portion of the signal present in its own frequency range or band.