Active notch filter

摘要

A method and apparatus are disclosed for filtering a signal, such as a transmit communication signal with a configurable notch filter. The configurable notch filter may attenuate a set of frequencies near a selected notch frequency. In some embodiments, the configurable notch filter may include a variable resistor, a variable capacitor, a first inductor, and a second inductor. The variable resistor may be configured to compensate for resistive losses within the configurable notch filter. The variable capacitor may be configured to determine the set of frequencies to be attenuated.

主权项

1. A configurable notch filter to attenuate a set of frequencies within a transmit communication signal near a notch frequency, the configurable notch filter comprising:
a first inductive element to receive the transmit communication signal; a second inductive element magnetically coupled to the first inductive element; and a first variable capacitor electrically coupled in parallel to the second inductive element, the first variable capacitor having a first capacitance value that is directly proportional to an inductance value of the first inductive element and is inversely proportional to an inductance value of the second inductive element.