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US 4,382,233 AGranted
Multiple-feedback path filter
AssigneeTektronix, Inc.
InventorBruce E. Hofer
Life of this patent
Estimating the term…
Abstract
A multiple-feedback path bandpass/bandreject filter which exhibits a nearly constant Q over a predetermined frequency range, and which is tunable by means of a single variable impedance element is provided. A Thevenin equivalent voltage source is placed in series with the tuning element, wherein the Thevenin voltage is a predetermined constant fractional amplitude of the bandreject output voltage, or its equivalent.
Claims4
A multiple feedback path filter comprising in combination:
- an operational amplifier having a plurality of feedback paths from output to input, said feedback paths including one or more impedance elements;
- a single variable-impedance tuning element connected to said operational amplifier;
- and
- means for applying a voltage to said variable-impedance tuning element to effect a nearly constant Q over a predetermined frequency range.
1 more element
Dependencies are inferred from the claim text.