| Also known as “Q”,
the resonance of
a filter is the measure of the amount of feedback from the filter’s output
to its input. Filters with high
“Q” will amplify the signal at the cut-off frequency and thereby narrow
the filter’s effective bandwidth. |
A good example of a filter with
a high Q is a wah wah pedal for the guitar: the familiar “wah” is
the sound of a swept low pass filter with high Q. |
Some filters permit the Q to increase to the point
of feedback,
at which point the filter becomes a sine oscillator. |