# US 11,451,319 B2 · High-frequency signal transmission-reception circuit > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,451,319 B2 - Document ID: US11451319B2 - Status: Granted - Kind: B2 - Application number: 17/103,175 - Filed: 2020-11-24 - Published: 2021-05-27 - Granted: 2022-09-20 - Earliest claimed: 2019-11-25 - Assignees: Murata Manufacturing Co., Ltd. - Applicants: Murata Manufacturing Co., Ltd. - Inventors: Kazuhiro Takahashi - Web page: https://patentgrep.com/patent/US11451319B2 ## CPC - H04K 3/22: {including jamming detection and monitoring} - H03F 3/195: in integrated circuits - H03F 3/245: {with semiconductor devices only} - H04B 1/40: Circuits - H04B 1/401: for selecting or indicating operating mode - H04B 1/525: with means for reducing leakage of transmitter signal into the receiver - H03F 2200/294: the amplifier being a low noise amplifier [LNA] - H03F 2200/451: the amplifier being a radio frequency amplifier - H04K: SECRET COMMUNICATION; JAMMING OF COMMUNICATION - H03F: AMPLIFIERS - H04B: TRANSMISSION ## Abstract A high-frequency circuit includes a transmission circuit that transmits a high-frequency signal, a reception circuit that receives a high-frequency signal, and a multiplexer that separates a reception path and a transmission path for high-frequency signals. In the reception circuit, a filter circuit in which a first frequency response and a second frequency response different from the first frequency response can be switched in accordance with a jamming wave for a high-frequency signal to be received is provided in the reception path for a high-frequency signal. ## Claims ### Claim 1 A high-frequency signal transmission-reception circuit comprising: a high-frequency circuit configured to perform transmission and reception of high-frequency signals with one or more antenna ports, the high-frequency circuit comprising: a transmission circuit configured to transmit a high-frequency signal; a reception circuit configured to receive a high-frequency signal; a multiplexer configured to separate a reception path and a transmission path for the high-frequency signals; and a filter circuit in the reception path, wherein the filter circuit is configured to selectively switch between a first frequency response and a second frequency response in accordance with a jamming wave for a high-frequency signal, the second frequency response being different than the first frequency response, wherein the transmission circuit comprises a sub-controller configured to control a transmission operation in accordance with a control command from at least a main controller, wherein the reception circuit comprises a sub-controller configured to control a reception operation in accordance with the control command from at least the main controller, and wherein the sub-controller of the transmission circuit is configured to: perform control so that the filter circuit has the first frequency response when the transmission circuit is not performing a transmission operation, and perform control so that the filter circuit has the second frequency response when the transmission circuit is performing a transmission operation. ### Claim 2 (depends on 1) The high-frequency signal transmission-reception circuit according to claim 1, wherein the second frequency response has an attenuation pole outside a passband of a high-frequency signal that is received. ### Claim 3 (depends on 1) The high-frequency signal transmission-reception circuit according to claim 1, wherein the second frequency response has an attenuation pole at a frequency different from a frequency of an attenuation pole of the first frequency response, the frequency of the attenuation pole of the first frequency response being outside a passband of a high-frequency signal that is received. ### Claim 4 (depends on 1) The high-frequency signal transmission-reception circuit according to claim 1, wherein the filter circuit comprises an LC series resonant circuit. ### Claim 5 (depends on 1) The high-frequency signal transmission-reception circuit according to claim 1, wherein the filter circuit comprises a band pass filter circuit. ### Claim 6 (depends on 1) The high-frequency signal transmission-reception circuit according to claim 1, wherein the jamming wave is a second harmonic component of a high-frequency signal transmitted by the transmission circuit, and wherein the second frequency response has an attenuation pole that attenuates at least the second harmonic component. ### Claim 7 A high-frequency signal transmission-reception circuit, further comprising: a high-frequency circuit configured to perform transmission and reception of high-frequency signals with one or more antenna ports, the high-frequency circuit comprising: a transmission circuit configured to transmit a high-frequency signal; a reception circuit configured to receive a high-frequency signal; a multiplexer configured to separate a reception path and a transmission path for the high-frequency signals; a filter circuit in the reception path, wherein the filter circuit is configured to selectively switch between a first frequency response and a second frequency response in accordance with a jamming wave for a high-frequency signal, the second frequency response being different than the first frequency response; and a jamming wave detection circuit in a stage preceding the filter circuit, the jamming wave detection circuit being configured to detect the jamming wave superimposed in the reception path, wherein the transmission circuit comprises a sub-controller configured to control a transmission operation in accordance with a control command from at least a main controller, wherein the reception circuit comprises a sub-controller configured to control a reception operation in accordance with the control command from at least the main controller, and in accordance with the jamming wave detection circuit, and wherein the sub-controller of the reception circuit is configured to: perform control so that the filter circuit has the first frequency response when no jamming wave is detected by the jamming wave detection circuit, and perform control so that the filter circuit has the second frequency response when the jamming wave is detected by the jamming wave detection circuit. ### Claim 8 (depends on 7) The high-frequency signal transmission-reception circuit according to claim 7, wherein the second frequency response has an attenuation pole outside a passband of a high-frequency signal that is received. ### Claim 9 (depends on 7) The high-frequency signal transmission-reception circuit according to claim 7, wherein the second frequency response has an attenuation pole at a frequency different from a frequency of an attenuation pole of the first frequency response, the frequency of the attenuation pole of the first frequency response being outside a passband of a high-frequency signal that is received. ### Claim 10 (depends on 7) The high-frequency signal transmission-reception circuit according to claim 7, wherein the filter circuit comprises an LC series resonant circuit. ### Claim 11 (depends on 7) The high-frequency signal transmission-reception circuit according to claim 7, wherein the filter circuit comprises a band pass filter circuit. ### Claim 12 (depends on 7) The high-frequency signal transmission-reception circuit according to claim 7, wherein the jamming wave is a second harmonic component of a high-frequency signal transmitted by the transmission circuit, and wherein the second frequency response has an attenuation pole that attenuates at least the second harmonic component.