# US 12,119,800 B2 · Signal transmission circuit and signal transmission system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,119,800 B2 - Document ID: US12119800B2 - Status: Granted - Kind: B2 - Application number: 17/633,123 - Filed: 2020-05-11 - Published: 2022-09-01 - Granted: 2024-10-15 - Earliest claimed: 2019-08-07 - Assignees: Hitachi Astemo, Ltd. - Applicants: Hitachi Astemo, Ltd. - Inventors: Yutaka Uematsu; Hideyuki Sakamoto - Web page: https://patentgrep.com/patent/US12119800B2 ## CPC - H03H 7/0153: {Electrical filters; Controlling thereof} - B60R 16/023: for transmission of signals between vehicle parts or subsystems - H03H 7/46: Networks for connecting several sources or loads, working on different frequencies or frequency bands, to a common load or source - H04B 3/02: Details - H04L 25/02: Details {; arrangements for supplying electrical power along data transmission lines (systems for transmitting signals via power distribution lines H04B3/54)} - H03H 7/1775: {Parallel LC in shunt or branch path (H03H7/1791 takes precedence)} - H03H 2007/013: {Notch or bandstop filters} - H03H: IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS (waveguides, resonators, lines or other devices of the waveguide type H01P) - B60R: VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR - H04B: TRANSMISSION - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract A signal transmission circuit includes a common frequency filter configured to filter a signal centering on a common frequency that is an anti-resonance frequency; a first frequency filter configured to filter a signal centering on a first frequency that is an anti-resonance frequency; a second frequency filter configured to filter a signal centering on a second frequency that is an anti-resonance frequency; a first route connected to a first signal wiring line configured to transmit a digital signal; and a second route connected to a second signal wiring line configured to transmit a digital signal. The first route has the common frequency filter connected to a power supply circuit, and the first frequency filter disposed between the common frequency filter and the first signal wiring line and connected in series to the common frequency filter, the second route has the common frequency filter, and the second frequency filter disposed between the common frequency filter and the second signal wiring line and connected in series to the common frequency filter, and both the first frequency and the second frequency are equal to or higher than the common frequency. ## Claims ### Claim 1 A signal transmission circuit comprising: a common frequency filter configured to filter a signal centering on a common frequency that is an anti-resonance frequency; a first frequency filter configured to filter a signal centering on a first frequency that is an anti-resonance frequency; a second frequency filter configured to filter a signal centering on a second frequency that is an anti-resonance frequency; a first route connected to a first signal wiring line configured to transmit a first digital signal; and a second route connected to a second signal wiring line configured to transmit a second digital signal, wherein the first route has the common frequency filter connected to a power supply circuit, and the first frequency filter disposed between the common frequency filter and the first signal wiring line and connected in series to the common frequency filter, the second route has the common frequency filter, and the second frequency filter disposed between the common frequency filter and the second signal wiring line and connected in series to the common frequency filter, and both the first frequency and the second frequency are equal to or higher than the common frequency. ### Claim 2 (depends on 1) The signal transmission circuit according to claim 1, wherein the common frequency filter has a larger volume than the first frequency filter and the second frequency filter. ### Claim 3 (depends on 1) The signal transmission circuit according to claim 1, wherein the common frequency is lower than the first frequency and the second frequency. ### Claim 4 (depends on 1) The signal transmission circuit according to claim 1, wherein the first frequency, the second frequency, and the common frequency have the same value. ### Claim 5 (depends on 1) The signal transmission circuit according to claim 1, wherein the first route further has a third frequency filter between the first frequency filter and the first signal wiring line, the third frequency filter configured to filter a signal centering on a third frequency that is an anti-resonance frequency, the second route further has a fourth frequency filter between the second frequency filter and the second signal wiring line, the fourth frequency filter configured to filter a signal centering on a fourth frequency that is an anti-resonance frequency, and the common frequency is equal to or less than any of the first frequency, the second frequency, the third frequency, and the fourth frequency. ### Claim 6 (depends on 1) The signal transmission circuit according to claim 1, further comprising: a third frequency filter configured to filter a signal centering on a third frequency that is an anti-resonance frequency; a fourth frequency filter configured to filter a signal centering on a fourth frequency that is an anti-resonance frequency; a third route connected to a third signal wiring line configured to transmit a third digital signal; and a fourth route connected to a fourth signal wiring line configured to transmit a fourth digital signal, wherein the third route has the common frequency filter, and the third frequency filter disposed between the common frequency filter and the third signal wiring line and connected in series to the common frequency filter, the fourth route has the common frequency filter, and the fourth frequency filter disposed between the common frequency filter and the fourth signal wiring line and connected in series to the common frequency filter, and the common frequency is lower than any of the first frequency, the second frequency, the third frequency, and the fourth frequency. ### Claim 7 (depends on 1) The signal transmission circuit according to claim 1, further comprising a second common frequency filter configured to filter a signal centering on a second common frequency that is an anti-resonance frequency, wherein the first route further has the second common frequency filter connected in series between the common frequency filter and the first frequency filter, the second route further has the second common frequency filter connected in series between the common frequency filter and the second frequency filter, the second common frequency is equal to or higher than the common frequency, and both the first frequency and the second frequency are equal to or higher than the second common frequency. ### Claim 8 (depends on 1) The signal transmission circuit according to claim 1, wherein the common frequency filter has a functional safety switch between the common frequency filter and one of the first and second frequency filters connected to the common frequency filter, the functional safety switch configured to detect overcurrent and a short circuit to ground and protect a power supply. ### Claim 9 (depends on 1) A signal transmission system configured to connect a camera and an ECU module by a plurality of signal wiring lines including the first signal wiring line and the second signal wiring line, wherein a plurality of cameras are connected to the ECU module, and a configuration of a PoC filter configuring an inside of the ECU module has a configuration of the signal transmission circuit according to claim 1.