Notch filter and method
AssigneeTropian, Inc.
InventorsRonald A. Meck, Earl W. McCune, Jr., Edwin R. Twitchell
Life of this patent
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Abstract
An apparatus and method are provided for attenuating an undesired frequency (f1) relative to a desired frequency (f0) in a signal transmitted from an out-put (220) of an active element (210). Generally, the apparatus includes a parallel-resonant trap (145) coupled to the output of the active element (210), the trap including a network of reactive elements (235).
Claims2
A method of modifying a filter design including a reactive element of a first type and having a given filter response having a given comer frequency to add to a response of the filter a notch characteristic occurring at a desired notch frequency, comprising:
- adding a reactive element of a second type to the reactive element of the first type to form one of a series-resonant combination and a parallel-resonant combination;
- determining by formula a value of the reactive element of the second type as a function of the value of the reactive element of the first type, the comer frequency, and the notch frequency;
- and
- determining by formula a new value of the reactive element of the first type as a function of an old value of the reactive element of the first type, the comer frequency, and the notch frequency.
Dependencies are inferred from the claim text.