The gradual reduction in gain or signal response at the upper or lower frequency limits of a circuit. In filter design, engineers measure how steeply a signal attenuates beyond the cutoff frequency, typically expressing the slope in decibels per octave or decade. A steep slope creates a sharp boundary, while a gentle slope allows more out-of-band frequencies to pass.
We need the low-pass filter to roll off at 20 kilohertz to cut out the switching noise.
Related terms
Lowpass
A type of filter that allows low-frequency signals to pass while blocking higher frequencies.
Band-pass
Describing a circuit or filter that allows a specific range of frequencies to pass while blocking those outside the range.
Band-stop
Describing a circuit or filter that blocks a specific range of frequencies while allowing all others to pass.