Patent ID: 7738610

Claim:
A system for reducing an interfering signal in a radio signal, the system comprising: a first notch filter having first and second inputs and having an output, said first input of said first notch filter configured to receive the radio signal, said first notch filter configured to produce a first filtered signal at said output of said first notch filter; a signal analyzer having an input configured to receive an intermediate frequency (IF) signal and having an output, said IF signal based on said first filtered signal, said signal analyzer configured to detect an energy content in said radio signal; an amplifier having an input coupled to said output of said first notch filter and having an output; a processing unit having an input coupled to said output of said signal analyzer and having an output coupled to said second input of said first notch filter, said processing unit configured to: a) determine a frequency of the interfering signal and monitor an energy in the interfering signal; b) tune said first notch filter to an initial tune value; wherein the initial tune value indicates a previously determined interfering signal; c) detect an energy content in said radio signal; d) tune said first notch filter away from said initial tune value while monitoring said energy in the interfering signal; e) repeat c)-d) until said energy in the interfering signal is at least partially minimized at a new tune value for tuning of said first notch filter; and f) store the new tune value as said initial tune value for future alignment of said first notch filter and to compensate for changes in operation of said first notch filter; and a second notch filter having a first input coupled to said output of said amplifier, a second input coupled to said output of said processing unit, and an output, said second notch filter configured to produce a second filtered signal from said first filtered signal at said output of said second notch filter.