Controlling Q-factor of filters
First Claim
1. A method of controlling a Q-factor for a filter, the method comprising:
- stabilizing an active feedback to provide a variable feedback in said filter;
varying the active feedback based on an input signal to said filter; and
in response to the variable feedback, producing a desired Q-factor for said filter at a first frequency band.
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Abstract
The present invention provides a method and an apparatus for controlling a Q-factor for a filter. The method comprises stabilizing an active feedback to provide a variable feedback in a filter, varying the active feedback based on an input signal to the filter, and producing a desired Q-factor for the filter at a first frequency band, in response to the variable feedback. The method further comprises reconfiguring a center frequency and a bandwidth of the filter based on a channel bandwidth of the input signal to the filter to adjust the Q-factor for the filter in response to a second frequency band different than the first frequency band. By reconfiguring a center frequency and a bandwidth of a filter, the Q-factor for the filter, such as a flexible or reconfigurable filter, may be controlled across a multiplicity of frequency band signals. Using software, for example, a common signal path may be provided for the multiplicity of frequency band signals within a frequency agile radio of a base station by tuning the radio based on a variable feedback through realization of a negative parallel resistance. Thus, tuneability of the Q-factor may provide frequency agile radios that include flexible or reconfigurable filters in a base station to serve different frequency bands without changing hardware. In this way, significant savings associated with frequency agility may be obtained.
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Citations
35 Claims
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1. A method of controlling a Q-factor for a filter, the method comprising:
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stabilizing an active feedback to provide a variable feedback in said filter;
varying the active feedback based on an input signal to said filter; and
in response to the variable feedback, producing a desired Q-factor for said filter at a first frequency band. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A filter comprising:
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a resonant circuit having an input terminal and an output terminal; and
a feedback path coupled to said resonant circuit, stabilization of feedback in said feedback path to provide a variable feedback, wherein said resonant circuit to stabilize an active feedback in said filter, vary the active feedback based on an input signal to said filter and produce a desired Q-factor for said filter at a first frequency band in response to the variable feedback. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30)
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31. An article comprising a computer readable storage medium storing instructions that, when executed cause a system to:
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stabilize an active feedback to provide a variable feedback in said filter;
vary the active feedback based on an input signal to said filter; and
produce a desired Q-factor for said filter at a first frequency band in response to the variable feedback. - View Dependent Claims (32, 33, 34, 35)
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Specification