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US 6,492,865 B1Granted
Band pass filter from two filters
AssigneeAcoustic Technologies, Inc.
InventorSamuel L. Thomasson
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Abstract
A band pass filter includes a pair of filters having different center frequencies and a difference amplifier coupled to the outputs of the filters. The filters preferably have response curves that intersect at −3 dB. The separation of the center frequencies determines, in part, the ripple in the response curve of the band pass filter.
Claims14
A filter for electrical signals, said filter comprising:
- an input;
- a first channel coupled to said input and including a first filter having a first center frequency;
- a second channel coupled to said input and including a second filter having a second center frequency;
- wherein the first center frequency and the second center frequency are not equal;
- and
- a difference amplifier coupled to said channels for subtracting the signals from the channels;
- whereby the difference amplifier produces an output signal characteristic of a bandpass filter.
4 more elements
A method for processing an electrical signal, said method comprising the steps of:
- applying the electrical signal to a pair of filters having separate center frequencies;
- and
- subtracting the output of one filter from the output of the other filter to produce an output signal characteristic of a band pass filter.
A filter for electrical signals, said filter comprising:
- a first channel including a first filter having a first center frequency;
- a second channel including a second filter having a second center frequency;
- wherein the frequency response curve of the first filter intersects the frequency response curve of the second filter;
- and
- a difference amplifier coupled to said channels for subtracting signals from the channels to produce an output signal characteristic of a bandpass filter having a center frequency between said first center frequency and said second center frequency.
2 more elements
Dependencies are inferred from the claim text.