| The "notch"
can be adjusted to a specific frequency, depth and width. The most versatile
type of notch filter is the "parallel notch filter" or "parallel
trap circuit"; these are two different names for a combination of a
resistor, inductor, and capacitor in parallel.These filters are very difficult
to design, due to the complex interactions of the non-ideal portions of
each componentThe advantages of a parallel notch filter are that they work
independently from the impedance of the driver, and can be added to an existing