9
Filter:
A circuit that removes some frequencies and allows other frequencies to pass
through the circuit.
A filter has a
cutoff frequency
that determines the point at which frequencies begin
to be removed.
A
lowpass
filter is one in which frequencies above the cutoff frequency are removed
and all frequencies below the cutoff are passed through.
A
highpass
filter is one in which frequencies below the cutoff frequency are
removed and frequencies above the cutoff are passed through.
A
bandpass
filter has two cutoff frequencies that define a frequency band, outside
of which the frequencies are removed (figure 7).
