Tunable filter
AssigneeHuawei Technologies Co., Ltd.
InventorGiuseppe Gramegna
Life of this patent
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Abstract
The disclosure relates to a tunable filter. The tunable filter includes: a filter input; a filter output; at least one feedback loop coupled between the filter output and the filter input, where the at least one feedback loop includes at least one tunable feedback capacitance which is configured to tune a cut-off frequency of the tunable filter; and an active element, coupled between the filter input and the filter output and configured to drive the at least one tunable feedback capacitance, the active element having a transfer function with a primary pole and at least one secondary pole, where the active element includes a first stabilization element that is coupled to a first internal node of the active element.
Claims20
A tunable filter comprising:
- a filter input;
- a filter output;
- at least one feedback loop coupled between the filter output and the filter input, wherein the at least one feedback loop comprises at least one tunable feedback capacitance which is configured to tune a cut-off frequency of the tunable filter;
- and
- an active element coupled between the filter input and the filter output and configured to drive the at least one tunable feedback capacitance, said active element having a transfer function with a primary pole and at least one secondary pole,
- wherein the active element comprises a first stabilization element that is coupled to a first internal node of the active element,
- wherein the first stabilization element is configured to establish a linear relationship between a location of the primary pole and a location of the at least one secondary pole of the active element.
An apparatus comprising a tunable filter, wherein the tunable filter comprises:
- a filter input;
- a filter output;
- at least one feedback loop coupled between the filter output and the filter input, wherein the at least one feedback loop comprises at least one tunable feedback capacitance which is configured to tune a cut-off frequency of the tunable filter;
- and
- an active element, coupled between the filter input and the filter output and configured to drive the at least one tunable feedback capacitance, said active element having a transfer function with a primary pole and at least one secondary pole,
- wherein the active element comprises a first stabilization element that is coupled to a first internal node of the active element,
- wherein the first stabilization element is configured to establish a linear relationship between a location of the primary pole and a location of the at least one secondary pole of the active element.
A method of making a tunable filter comprising:
- providing a filter input, and a filter output;
- connecting at least one feedback loop between the filter output and the filter input, wherein the at least one feedback loop comprises at least one tunable feedback capacitance which is configured to tune a cut-off frequency of the tunable filter;
- and
- connecting an active element between the filter input and the filter output, wherein the active element is configured to drive the at least one tunable feedback capacitance, and the active element has a transfer function with a primary pole and at least one secondary pole,
- wherein the active element comprises a first stabilization element that is coupled to a first internal node of the active element,
- wherein the first stabilization element is configured to establish a linear relationship between a location of the primary pole and a location of the at least one secondary pole of the active element.
Dependencies are inferred from the claim text.