The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.

The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.

Date of Patent:
Dec. 31, 2013

Filed:

Mar. 03, 2006
Applicants:

Hongying Sheng, San Jose, CA (US);

Jun Wang, Cupertino, CA (US);

Inventors:

Hongying Sheng, San Jose, CA (US);

Jun Wang, Cupertino, CA (US);

Assignee:
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H03B 1/00 (2006.01); H03K 5/00 (2006.01); H04B 1/10 (2006.01); G06G 7/19 (2006.01);
U.S. Cl.
CPC ...
Abstract

A filter network having a variable cut-off frequency can be controlled in a way that allows the cut-off frequency to be changed gradually to avoid undesirable transient effects. An impedance network (such as a resistor network) that provides a plurality of impedance values is provided. Logic, and a corresponding method, are provided to change the impedance value gradually, such as on a step-wise basis, to change the cut-off frequency gradually. The size of the impedance step and the duration of the step can be preprogrammed, and may be different for different types of events that trigger the need for a frequency change. It may also be possible for those preprogrammed values to be initial values only, with the values changing under programmed control during the frequency changing process. Other values, such as the initial and target impedance values that determine the initial and target frequency, also may be programmable.


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