Bi-quad calibration
AssigneeSpero Devices, Inc.
InventorDev V. Gupta
Life of this patent
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Abstract
Embodiments include methods of tuning state variable filters. Examples include state variable filters whose center frequencies can be tuned using variable gain blocks coupled to outputs of filter integrators. First- and second-order state variable filters may operate on signals in parallel and their outputs combined to produce a filtered output. Filters may be tuned to pass or reject signals depending on the application; sample applications include, but are not limited to: agile filtering; spectrum analysis; interference detection and rejection; equalization; direct intermediate-frequency transmission; and single-sideband modulation and demodulation.
Claims9
A method of tuning a filter of a biquad circuit, the biquad circuit comprising analog circuit components including a loss pad, a first integrator, and a second integrator, the method comprising:
- tuning the loss pad to generate a target gain value at a predetermined frequency;
- tuning a phase of the first integrator to a target phase at the predetermined frequency;
- tuning a phase of the second integrator to the target phase at the predetermined frequency;
- and
- tuning a gain of the first integrator to the target gain value at the predetermined frequency;
- and
- tuning a gain of the second integrator to the target gain value at the predetermined frequency;
- wherein each tuning step comprises changing circuit values.
Dependencies are inferred from the claim text.