Wideband active radio frequency interference cancellation system

• US 9,479,214 B2
• Filed: 11/25/2014
• Issued: 10/25/2016
• Est. Priority Date: 11/25/2013
• Status: Active Grant

• Current Assignee: Raytheon Company (Rtx Corporation)
• Original Assignee: Raytheon Company (Rtx Corporation)
• Inventors: Webb, Kenneth M., Hall, Charles A., Srivastava, Tina P., McDowell, Anthony T.
• Primary Examiner(s): Chen, Junpeng
• Application Number:
  US14/553,076
• Publication Number:
  US 20150155899A1
• Time in Patent Office: 700 Days
• US Class Current: 1/1
• CPC Class Codes: H04B 1/525 with means for reducing leakage of transmitter signal into the receiver

Abstract

A wideband radio frequency (RF) interference cancellation system includes an electronic channel canceller configured to split an electronic reference signal output from an electronic transmitting element into a plurality of band signals. At least one electronic band pass filter is configured to receive a respective band signal delivered to a respective channel. The wideband RF interference cancellation system further includes at least one electronic tunable cancellation element configured to tune the respective channel such that reflections are canceled before being input to receiving element.

Claims

1. A wideband radio frequency (RF) interference cancellation system, comprising:

an electronic channel canceller configured to split an electronic reference signal output from an electronic transmitting element into a plurality of band signals;

an electronic receiving element configured to receive the electronic reference signal;

a low pass filter, a mid pass filter, and a high pass filter each in electrical communication with the channel canceller, the at least one electronic band pass filter configured to receive a respective band signal delivered to a respective channel; and

at least one electronic tunable cancellation element in electrical communication with a respective band pass filter, the at least one tunable cancellation element configured to tune the respective channel such that reflections are canceled before being input to receiving element,

wherein the at least one electronic tunable cancellation element includes a first electronic tunable cancellation element interposed between the low pass filter, a second electronic tunable cancellation element interposed between the mid pass filter, and a third electronic tunable cancellation element interposed between the high pass filter.

2. The wideband RF interference cancellation system of claim 1, wherein the first, second, and third tunable cancellation elements each have a different frequency response setting with respect to one another.

3. The wideband RF interference cancellation system of claim 2, further comprising:

an electronic signal detector having an input interposed between a transmission path and the receiving element, the signal detector configured to determine at least one signal characteristic of a transmission signal traveling on the transmission line; and

an electronic canceller microcontroller in electrical communication with the signal detector and configured to control at least one of the first, second, and third electronic tunable cancellation elements to actively tune a respective channel based on the at least one signal characteristic of the transmission signal.

4. The wideband RF interference cancellation system of claim 3, wherein the at least one characteristic of the transmission signal is determined before delivering the transmission signal to the receiving element.

5. The wideband RF interference cancellation system of claim 4, wherein the at least one characteristic of the transmission signal includes at least one of a reflection of the transmission signal, leakage of the transmission signal, a voltage level of the transmission signal, and a frequency of the transmission signal.

6. The wideband RF interference cancellation system of claim 5, wherein a portion of transmission signal is diverted to the first, second, and third electronic tunable cancellation elements to determine the at least one signal characteristic.

7. The wideband RF interference cancellation system of claim 6, wherein at least one of the first, second and third tunable cancellation elements sample the portion of the transmission signal and outputs a sampled cancellation signal to a receiving line connected to an input of the receiving element.

8. The wideband RF interference cancellation system of claim 7, wherein the sampled cancellation signal cancels leakage existing on the receiving line.

9. A method of actively cancelling interference from a wideband radio frequency system, the method comprising:

generating a transmission signal to be delivered to a receiving element;

splitting the transmission signal into a plurality of band signals;

receiving at least one band signal delivered to a respective channel using a low pass filter to receive respective low pass band signal, a mid pass filter to receive a respective mid pass band signal, and a high pass filter to receive a respective a high pass band signal;

sampling a portion of the transmission signal using first, second, and third tunable cancellation elements connected to outputs of the low pass, mid pass, and high pass filters, respectively; and

tuning the respective channel such that reflections are canceled before being input to the receiving element.

10. The method of claim 9, wherein the first, second, and third tunable cancellation elements each have a different frequency response setting with respect to one another.

11. The method of claim 10, further comprising:

determining at least one signal characteristic of a transmission signal traveling on the transmission line; and

controlling at least one of the first, second, and third electronic tunable cancellation elements to actively tune a respective channel based on the at least one signal characteristic of the transmission signal.

12. The method of claim 11, further comprising determining the at least one characteristic of the transmission signal before delivering the transmission signal to the receiving element.

13. The method of claim 12, wherein the at least one characteristic of the transmission signal includes at least one of a reflection of the transmission signal, leakage of the transmission signal, a voltage level of the transmission signal, and a frequency of the transmission signal.

14. The method of claim 13, further comprising diverting the portion of transmission signal to the first, second, and third electronic tunable cancellation elements to determine the at least one signal characteristic.

15. The method of claim 14, further comprising sampling the portion of the transmission signal using at least one of the first, second and third tunable cancellation elements and outputting a sampled cancellation signal to a receiving line connected to an input of the receiving element.

16. The method of claim 15, further comprising cancelling leakage on the receiving line using the sampled cancellation signal.