Integrated tunable RF notch filter

A method of filtering in a radio frequency front-end, the method comprising:

• receiving a radio frequency input signal and amplifying the radio frequency input signal to generate an amplified RF signal;
• downconverting the amplified RF signal to generate a baseband signal;
• generating hard-decision samples of ones and zeroes from the baseband signal;
• analyzing the hard-decision samples to detect at least one interferer and to generate a control signal for control of filtering of at least one frequency range of the amplified RF signal corresponding to the at least one interferer;
• and
• notch filtering out the at least one frequency range from the amplified RF signal based at least partly on the control signal to filter out the at least one interferer.

A method of filtering an interferer in a radio frequency front-end, the method comprising:

• receiving a radio frequency input signal and amplifying the radio frequency input signal to generate an amplified RF signal;
• downconverting the amplified RF signal to generate a baseband signal;
• generating hard-decision samples of ones and zeroes from the baseband signal;
• analyzing the hard-decision samples to generate a control signal for control of filtering of at least one frequency range of the amplified RF signal;
• filtering out the at least one frequency range from the amplified RF signal based at least partly on the control signal;
• and
• computing Fourier Transforms of the hard-decision samples to generate an estimate of a frequency of the interferer or the at least one filter frequency of filtering.

A method of locating a contour of optimal attenuation for a notch filter having a two-dimensional control characteristic so that both frequency and depth of filtering vary according to variation with a first control input and a second control input, the method comprising:

• (a) activating broadband noise in a front-end of a wireless receiver for calibration;
• (b) filtering the broadband noise in the front-end of the wireless receiver with the notch filter;
• (c) selecting an initial settings for the first control input of the notch filter, and then performing (d)-(f):
• (d) observing a frequency response of the notch filter for a first plurality of settings of the second control input, wherein the first plurality of settings cover a first range and are spaced apart at a first spacing;
• (e) observing the frequency response of the notch filter for a second plurality of settings of the second control input, wherein the second plurality of settings cover a second range that is smaller than the first range and covers a frequency response observation from the first range that has the deepest notch characteristic, and wherein the second plurality of settings are spaced apart by a second spacing that is tighter than the first spacing;
• (f) collecting the setting from within the second plurality of setting having the deepest notch characteristic for the particular settings of the first control input and the second control input;
• (g) repeating (d)-(f) for other settings of the first control input;
• and
• (h) determining a contour for control of the notch filter based on the collected setting for the first control input and the second control input having the deepest notch characteristic.

An apparatus comprising:

• (a) a controllable source of broadband noise;
• (b) a notch filter having a two-dimensional control characteristic so that both frequency and depth of filtering vary according to variation with a first control input and a second control input;
• and
• (c) a processor configured to control activation of the controllable source of broadband noise and control filtering by the notch filter, the processor configured to select an initial settings for the first control input of the notch filter, and then is configured to (d)-(f):
• (d) observe a frequency response of the notch filter for a first plurality of settings of the second control input, wherein the first plurality of settings cover a first range and are spaced apart at a first spacing;
• (e) observe the frequency response of the notch filter for a second plurality of settings of the second control input, wherein the second plurality of settings cover a second range that is smaller than the first range and covers a frequency response observation from the first range that has the deepest notch characteristic, and wherein the second plurality of settings are spaced apart by a second spacing that is tighter than the first spacing;
• (f) collect the setting from within the second plurality of setting having the deepest notch characteristic for the particular settings of the first control input and the second control input;
• (g) wherein the processor is configured to repeat (d)-(f) for other settings of the first control input;
• (h) wherein the processor is configured to determine a contour for control of the notch filter based on the collected setting for the first control input and the second control input having the deepest notch characteristic.