# US 2026/0076609 A1 · Sympathetic nervous signal sensing system and method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2026/0076609 A1 - Document ID: US20260076609A1 - Status: Published application - Kind: A1 - Application number: 19/333,025 - Filed: 2025-09-18 - Published: 2026-03-19 - Earliest claimed: 2024-09-18 - Assignees: National Tsing Hua University - Applicants: National Tsing Hua University - Inventors: TING-WEI WANG - Web page: https://patentgrep.com/patent/US20260076609A1 ## CPC - A61B 5/4035: {Evaluating the autonomic nervous system} - A61B 5/308: for electrocardiography [ECG] - A61B 5/311: for nerve conduction study [NCS] - A61B 5/318: Heart-related electrical modalities, e.g. electrocardiography [ECG] - A61B 5/388: Nerve conduction study, e.g. detecting action potential of peripheral nerves - A61B 5/7225: {Details of analogue processing, e.g. isolation amplifier, gain or sensitivity adjustment, filtering, baseline or drift compensation (input circuits for detecting, measuring, or recording bioelectric or biomagnetic signals A61B5/30; specific diagnostic methods using bioelectric or biomagnetic signals A61B5/316)} - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) ## Abstract The sympathetic nervous signal sensing system includes an electrode pair, a high input impedance receiving circuit, a differential circuit, and a post-processing circuit. The electrode pair is arranged on a target and includes a first electrode configured to receive a first signal and a second electrode configured to receive a second signal. The high input impedance receiving circuit includes a first follower configured to receive a first signal and output a third signal, and a second follower configured to receive a second signal and output a fourth signal. The differential circuit is configured to perform differential processing on the third signal and the fourth signal to generate a fifth signal. The post-processing circuit is configured to filter the fifth signal according to a first filtering frequency band to output a sympathetic nervous signal. ## Claims ### Claim 1 A sympathetic nervous signal sensing system, comprising: an electrode pair disposed outside a sympathetic nervous signal source of a target, wherein the electrode pair includes: a first electrode configured to receive a first signal; and a second electrode configured to receive a second signal; a high input impedance receiving circuit coupled to the electrode pair, wherein the high input impedance receiving circuit includes: a first follower configured to receive the first signal and output a third signal approximately equal to the first signal; and a second follower configured to receive the second signal and output a fourth signal approximately equal to the second signal; a differential circuit coupled to the high input impedance receiving circuit, wherein the differential circuit is configured to perform a differential process on the third signal and the fourth signal to generate a fifth signal; and a post-processing circuit coupled to the high input impedance receiving circuit, wherein the post-processing circuit is configured to filter the fifth signal with a first filtering band to output a sympathetic nervous signal. ### Claim 2 (depends on 1) The sympathetic nervous signal sensing system of claim 1, further comprising: a common-mode electrode configured to receive a common-mode signal corresponding to the first signal; and wherein the differential circuit is further configured to perform the differential process on the common-mode signal with the third signal and the fourth signal respectively. ### Claim 3 (depends on 1) The sympathetic nervous signal sensing system of claim 1, further comprising a backend device configured to receive the sympathetic nervous signal and perform at least one signal processing on the sympathetic nervous signal. ### Claim 4 (depends on 1) The sympathetic nervous signal sensing system of claim 1, wherein the post-processing circuit is further configured to filter the fifth signal with a second filtering band to output an electrocardiogram (ECG) signal. ### Claim 5 (depends on 1) The sympathetic nervous signal sensing system of claim 1, further comprising an AC coupling circuit coupled between the high input impedance receiving circuit and the differential circuit, wherein the AC coupling circuit is configured to remove DC components of the third signal and the fourth signal. ### Claim 6 (depends on 1) The sympathetic nervous signal sensing system of claim 1, further comprising a bias resistor coupled between an input terminal of the first follower and ground. ### Claim 7 (depends on 1) The sympathetic nervous signal sensing system of claim 1, further comprising a negative impedance circuit coupled between the electrode pair and the high input impedance receiving circuit, wherein the negative impedance circuit is configured to provide a negative impedance value approximately equal to a negative value of an equivalent impedance from the sympathetic nervous signal source to the electrode pair, to input terminals of the first follower and the second follower. ### Claim 8 (depends on 7) The sympathetic nervous signal sensing system of claim 7, further comprising a controller coupled between the post-processing circuit and the negative impedance circuit, wherein the controller is configured to adjust the negative impedance value of the negative impedance circuit based on at least one signal parameter of the sympathetic nervous signal. ### Claim 9 (depends on 7) The sympathetic nervous signal sensing system of claim 7, further comprising a controller coupled between the post-processing circuit and the negative impedance circuit, wherein: the post-processing circuit is further configured to filter the fifth signal with a second filtering band to output an electrocardiogram (ECG) signal; and the controller is configured to adjust the negative impedance value of the negative impedance circuit based on at least one signal parameter of the electrocardiogram signal. ### Claim 10 A sympathetic nervous signal sensing method, comprising: disposing an electrode pair outside a sympathetic nervous signal source of a target, the electrode pair comprising a first electrode configured to receive a first signal and a second electrode configured to receive a second signal; using a high input impedance receiving circuit to receive the first signal and output a third signal approximately equal to the first signal, and to receive the second signal and output a fourth signal approximately equal to the second signal; using a differential circuit to perform a differential process on the third signal and the fourth signal to generate a fifth signal; and using a post-processing circuit to filter the fifth signal with a first filtering band to output a sympathetic nervous signal. ### Claim 11 (depends on 10) The sympathetic nervous signal sensing method of claim 10, further comprising: disposing a common-mode electrode configured to receive a common-mode signal corresponding to the first signal; and further performing the differential process on the common-mode signal with the third signal and the fourth signal using the differential circuit. ### Claim 12 (depends on 10) The sympathetic nervous signal sensing method of claim 10, further comprising using a backend device to receive the sympathetic nervous signal and perform at least one signal processing on the sympathetic nervous signal. ### Claim 13 (depends on 10) The sympathetic nervous signal sensing method of claim 10, further comprising filtering the fifth signal with a second filtering band using the post-processing circuit to output an electrocardiogram (ECG) signal. ### Claim 14 (depends on 10) The sympathetic nervous signal sensing method of claim 10, further comprising using an AC coupling circuit to remove DC components of the third signal and the fourth signal. ### Claim 15 (depends on 10) The sympathetic nervous signal sensing method of claim 10, further comprising using a negative impedance circuit to provide a negative impedance value approximately equal to a negative value of an equivalent impedance from the sympathetic nervous signal source to the electrode pair, to an input terminal of the high input impedance receiving circuit. ### Claim 16 (depends on 15) The sympathetic nervous signal sensing method of claim 15, further comprising using a controller to adjust the negative impedance value of the negative impedance circuit based on at least one signal parameter of the sympathetic nervous signal. ### Claim 17 (depends on 15) The sympathetic nervous signal sensing method of claim 15, further comprising: filtering the fifth signal with a second filtering band using the post-processing circuit to output an electrocardiogram (ECG) signal; and using a controller to adjust the negative impedance value of the negative impedance circuit based on at least one signal parameter of the electrocardiogram signal.