Interference signal cancellation over a broad frequency range

1. A method of filtering a signal, the method comprising:

passing a first signal through a signal filter that at least partially cancels the first signal using a modulation system by:

(a) amplifying quadrature components of an input signal associated with the first signal,

(b) amplifying non-quadrature components of the input signal, and

(c) combining the amplified quadrature components from (a) and the amplified non-quadrature components from (b).

2. The method of claim 1 , wherein:

the quadrature components of the input signal are 90 degrees out of phase with each other; and

the non-quadrature components of the input signal are not 90 degrees out of phase with each other.

3. The method of claim 1 , wherein the signal filter comprises a tapped delay line having a first tap and a second tap separated by a delay line having a characteristic RF signal delay time; and

the modulation system includes a first modulator that receives an input signal from the first tap and a second modulator that receives an input signal from the second tap.

4. The method of claim 1 , wherein the first signal is received at an antenna that also generates the first signal.

5. The method of claim 1 , further comprising imparting separate signal weights to the quadrature and non-quadrature components of the input signal.

6. A signal filtering system comprising:

a signal filter that receives a first signal and is in communication with a receiver that also receives the first signal, the signal filter comprising:

(a) a modulation system that modulates the first signal, the modulation system being capable of amplifying quadrature components of an input signal associated with the first signal and amplifying non-quadrature components of the input signal, and

(b) a signal adder that combines the amplified quadrature and non-quadrature components of the input signal from (a) to generate filtered first signal and that communicates the filtered first signal to the receiver.

7. The system of claim 6 , wherein:

the quadrature components of the input signal are 90 degrees out of phase with each other; and

the non-quadrature components of the input signal are not 90 degrees out of phase with each other.

8. The system of claim 6 , wherein the signal filter further comprises:

a tapped delay line having a first tap and a second tap separated by a delay line having a characteristic RF signal delay time; and

the modulation system includes a first modulator that receives an input signal from the first tap and a second modulator that receives an input signal from the second tap.

9. The system of claim 6 , wherein the receiver receives the first signal at an antenna that also generates the first signal.

10. The system of claim 6 , wherein the signal filter further includes a signal weight adjuster connected to modulation system, the signal weight adjuster being adapted to impart separate signal weights to the quadrature and non-quadrature components of the input signal.

11. A method of transmitting and receiving radio frequency (RF) signals, the method comprising:

transmitting a transmit signal;

receiving a receive signal;

generating a filtered transmit signal including amplified quadrature and non-quadrature components of an input signal associated with the transmit signal; and

cancelling interference caused by the transmit signal to the receive signal using the filtered transmit signal.

12. The method of claim 11 , wherein the same antenna transmits the transmit signal and receives the receive signal.

13. The method of claim 11 , wherein the transmit signal and receive signal have overlapping frequencies.

14. The method of claim 11 , wherein the transmit signal is transmitted and the receive signal is received simultaneously.

15. The method of claim 11 , wherein the quadrature components of the input signal are 90 degrees out of phase with each other and the non-quadrature components of the input signal are not 90 degrees out of phase with each other.

16. The method of claim 11 , further comprising imparting separate signal weights to the quadrature and non-quadrature components of the input signal.

17. A radio frequency (RF) communications system comprising:

a transmitter that generates a transmit signal;

a signal filter that amplifies quadrature and non-quadrature components of an input signal associated with the transmit signal to produce a filtered transmit signal;

a receiver in communication with the signal filter and that receives a receive signal; and

a signal combiner that combines the filtered transmit signal with the receive signal.

18. The system of claim 17 , further comprising an antenna that transmits the transmit signal and receives the receive signal.

19. The system of claim 17 , wherein the transmitter and receiver transmit and receive at overlapping frequencies.

20. The system of claim 17 , wherein the quadrature components of the input signal are 90 degrees out of phase with each other and the non-quadrature components of the input signal are not 90 degrees out of phase with each other.

21. The system of claim 17 , the signal filter includes a signal weight adjuster adapted to impart separate signal weights to the quadrature and non-quadrature components of the input signal.