# US 2015/0146589 A1 · Feed-forward canceller > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2015/0146589 A1 - Document ID: US20150146589A1 - Status: Published application - Kind: A1 - Application number: 14/260,727 - Filed: 2014-04-24 - Published: 2015-05-28 - Earliest claimed: 2013-11-25 - Assignees: Raytheon Company - Applicants: Raytheon Company - Inventors: Kenneth M. Webb; Charles A. Hall; Tina P. Srivastava; Anthony T. McDowell - Web page: https://patentgrep.com/patent/US20150146589A1 ## CPC - H04L 5/1461: {Suppression of signals in the return path, i.e. bidirectional control circuits} - H04B 1/525: with means for reducing leakage of transmitter signal into the receiver - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) - H04B: TRANSMISSION ## Abstract A feed-forward cancellation system includes a transmitting element and a receiving element. The transmitting element is in electrical communication with a transmitting line. The transmitting element is configured output a transmission signal to the transmitting line. The receiving element is in electrical communication with a receiving line. The receiving element is configured to process a response signal that is generated in response to the transmission signal and that is delivered to the receiving line. At least one antenna is configured to transmit the transmission signal, receive the response signal generated based on the transmission signal, and deliver the response signal to the receiving line. The feed-forward cancellation system further includes an electronic cancellation unit configured to generate a cancellation signal based on the transmission signal. The cancellation signal eliminates saturation from at least one of the response signal and the receiving line. ## Claims ### Claim 1 A feed-forward cancellation system, comprising: a transmitting element in electrical communication with a transmitting line, the transmitting element configured to output a transmission signal to the transmitting line; a receiving element in electrical communication with a receiving line, the receiving element configured to process a response signal that is generated in response to the transmission signal and delivered to the receiving line; at least one antenna configured to perform at least one of: transmit the transmission signal, receive the response signal generated based on the transmission signal, and deliver the response signal to the receiving line; an electronic cancellation unit configured to generate a cancellation signal based on the transmission signal that eliminates saturation from at least one of the response signal and the receiving line. ### Claim 2 (depends on 1) The feed-forward cancellation system of claim 1, wherein the cancellation unit includes a digital signal processor having a first output that is in electrical communication with the transmitting line, and a second output that is in the electrical communication with the receiving line. ### Claim 3 (depends on 2) The feed-forward cancellation system of claim 2, wherein the saturation includes at least one of a leakage signal that leaks from transmitting line through the circulator, an antenna reflection signal that leaks from the antenna through the circulator, and an interference signal that is delivered independently from the antenna and onto the receiving line. ### Claim 4 (depends on 3) The feed-forward cancellation system of claim 3, wherein the at least one antenna is a single antenna configured to receive the transmission signal and transmit a response signal to the receiving line. ### Claim 5 (depends on 4) The feed-forward cancellation system of claim 4, further comprising a circulator in electrical communication with the antenna, the transmitting element and the receiving element, the circulator configured to deliver the transmission signal to the antenna and deliver the response signal to the receiving line. ### Claim 6 (depends on 5) The feed-forward cancellation system of claim 5, wherein the cancellation signal is phase-shifted with respect to the transmission signal. ### Claim 7 (depends on 6) The feed-forward cancellation system of claim 6, wherein the cancellation unit includes a combiner having a first input that receives the response signal from the circulator and a second input that receives the cancellation signal from the digital signal processor, the combiner configured to combine the cancellation signal with the response signal such that saturation of the response signal is eliminated. ### Claim 8 (depends on 7) The feed-forward cancellation system of claim 7, wherein the cancellation unit is configured to identify a type of saturation among a plurality of different saturation types, and to generate the cancellation signal in response to identifying the type of saturation. ### Claim 9 (depends on 8) The feed-forward cancellation system of claim 8, wherein the cancellation unit delivers the cancellation signal to receiving line prior to outputting the transmission signal. ### Claim 10 (depends on 9) The feed-forward cancellation system of claim 9, wherein the cancellation signal is phase-shifted 180 degrees with respect to the transmission signal. ### Claim 11 (depends on 1) The feed-forward cancellation system of claim 1, wherein the at least one antenna comprises: a transmitting antenna configured to receive the transmission signal from the transmitting line; and a receiving antenna located remotely from the transmitting antenna, the receiving antenna configured to receive the response signal and to deliver the response signal to the receiving line. ### Claim 12 (depends on 11) The feed-forward cancellation system of claim 11, wherein the electronic cancellation unit is configured to model a leakage path existing between the transmitting antenna and the receiving antenna, and to generate a digital cancellation signal based on the modeled leakage path. ### Claim 13 A method of eliminating saturation in a simultaneous transmitting and receiving system, the method comprising: delivering a transmission signal from the simultaneous transmitting and receiving system to at least one antenna; receiving via the at least one antenna a response signal that is based on the transmission signal and delivering the response signal to a receiving line of the simultaneous transmitting and receiving system; and generating a digital cancellation signal based on the transmission signal using the simultaneous transmitting and receiving system, the digital cancellation signal configured to eliminate saturation from at least one of the response signal and the receiving line. ### Claim 14 (depends on 13) The method of claim 13, further comprising phase-shifting the cancellation signal with respect to the transmission signal. ### Claim 15 (depends on 14) The method of claim 14, further comprising combining the cancellation signal to the response signal such that saturation of the response signal is eliminated. ### Claim 16 (depends on 15) The method of claim 15, further comprising identifying a type of saturation among a plurality of different saturation types, and generating the cancellation signal in response to identifying the type of saturation. ### Claim 17 (depends on 16) The method of claim 16, further comprising delivering the cancellation signal to receiving line prior to outputting the transmission signal. ### Claim 18 (depends on 17) The method of claim 17, further comprising phase-shifting the cancellation signal 180 degrees with respect to the transmission signal. ### Claim 19 (depends on 18) The method of claim 18, wherein the type of saturation includes at least one of a leakage signal that leaks from transmitting line through the circulator, an antenna reflection signal that leaks from the antenna through the circulator, an interference signal that is delivered independently from the antenna and onto the receiving line. ### Claim 20 (depends on 13) The method of claim 13, further comprising: delivering the transmission signal from the simultaneous transmitting and receiving system to a first antenna; receiving via a second antenna located remotely from the first antenna a response signal generated in response to the transmission via, and delivering the response signal to the receiving line; modeling a signal leakage path that exists between the first antenna and the second antenna; and generating the cancellation signal based on the modeled leakage path.