# US 11,307,712 B2 · Systems, methods, and devices for capacitive sensing with sinusoidal demodulation > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,307,712 B2 - Document ID: US11307712B2 - Status: Granted - Kind: B2 - Application number: 17/127,760 - Filed: 2020-12-18 - Published: 2021-10-07 - Granted: 2022-04-19 - Earliest claimed: 2020-04-07 - Assignees: Cypress Semiconductor Corporation - Applicants: Cypress Semiconductor Corporation - Inventors: Viktor Kremin; Oleksandr Pirogov; Vadym Grygorenko; Jens Weber - Web page: https://patentgrep.com/patent/US11307712B2 ## CPC - G06F 3/04182: {Filtering of noise external to the device and not generated by digitiser components} - H03K 17/962: {Capacitive touch switches} - G06F 3/04166: {Details of scanning methods, e.g. sampling time, grouping of sub areas or time sharing with display driving (Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally G06F3/04184)} - G06F 3/044: by capacitive means - G06F 3/0446: {using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes} - H03K 2217/960705: Safety of capacitive touch and proximity switches, e.g. increasing reliability, fail-safe - H03K 2217/96071: characterised by the detection principle - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) - H03K: PULSE TECHNIQUE (measuring pulse characteristics G01R; modulating sinusoidal oscillations with pulses H03C; transmission of digital information H04L; discriminator circuits detecting phase difference between two signals by counting or integrating cycles of oscillation H03D3/04; automatic control, starting, synchronisation or stabilisation of generators of electronic oscillations or pulses where the type of generator is irrelevant or unspecified H03L; coding, decoding or code conversion, in general H03M) ## Abstract Systems, methods, and devices improve the sensitivity of capacitive sensors. Devices may include an attenuator configured to receive an input from at least one sense electrode of a capacitive sensing device. The attenuator may be included in a sensing channel of a capacitive sensor. Devices may further include a signal generator coupled to an input of the attenuator. The signal generator may include one or more processors configured to generate a sinusoidal signal based, at least in part, on one or more noise characteristics of a scan sequence associated with one or more transmit electrodes of the capacitive sensing device, and provide the sinusoidal signal to the input of the attenuator. ## Claims ### Claim 1 A device comprising: an attenuator configured to receive an input from at least one sense electrode of a capacitive sensing device, the attenuator being included in a sensing channel of a capacitive sensor; a signal generator coupled to an input of the attenuator, the signal generator comprising one or more processors configured to: generate a sinusoidal signal based, at least in part, on one or more noise characteristics of a scan sequence associated with one or more transmit electrodes of the capacitive sensing device; and provide the sinusoidal signal to the input of the attenuator; and wherein the device further comprises: a mixer configured to combine the sinusoidal signal received from the signal generator and the input received from the at least one sense electrode, and further configured to generate an output based on the combining. ### Claim 2 (depends on 1) The device of claim 1, wherein the signal generator comprises a sinusoidal modulator. ### Claim 3 (depends on 1) The device of claim 1, wherein the mixer is a variable gain amplifier configured to change gain based on gain control signal. ### Claim 4 (depends on 1) The device of claim 1, wherein the signal generator is configured to use the sinusoidal signal to modulate a gain of the attenuator, and wherein the sinusoidal signal is a rectified sinusoidal signal. ### Claim 5 (depends on 1) The device of claim 1, wherein the signal generator is configured to provide the sinusoidal signal to the attenuator during the scan sequence. ### Claim 6 (depends on 1) The device of claim 1, wherein the signal generator is further configured to implement a window function. ### Claim 7 (depends on 1) The device of claim 1, wherein the at least one sense electrode and the one or more transmit electrodes are included in an electrode array of a capacitive touch screen. ### Claim 8 (depends on 1) The device of claim 1, wherein the signal generator is configured to be synchronous with a transmit signal generator, and wherein the transmit signal generator is configured to implement a phase offset value. ### Claim 9 (depends on 8) The device of claim 8, wherein the phase offset is determined based on a peak response of the capacitive sensor. ### Claim 10 A method comprising: generating a transmit drive signal based, at least in part, on one or more scanning parameters, the transmit drive signal being provided to one or more transmit electrodes of a capacitive sensing device; generating, using a signal generator, a sinusoidal signal based, at least in part, on one or more noise characteristics of the transmit drive signal and capacitive sensing device; receiving a sensed signal from at least one sense electrode of the capacitive sensing device; reducing the one or more noise characteristics in the sensed signal based, at least in part, on the sinusoidal signal; and wherein the reducing comprises: combining, using a mixer, the sensed signal with the sinusoidal signal at an input of an attenuator. ### Claim 11 (depends on 10) The method of claim 10, wherein the signal generator comprises a sinusoidal modulator. ### Claim 12 (depends on 10) The method of claim 10, wherein the mixer is a variable gain amplifier configured to change gain based on a gain control signal. ### Claim 13 (depends on 10) The method of claim 10, wherein the reducing comprises: modulating a gain of an attenuator based, at least in part, on the sinusoidal signal. ### Claim 14 A system comprising: a plurality of sense electrodes implemented in a capacitive sensing device; a plurality of transmit electrodes implemented in the capacitive sensing device; and an attenuator configured to receive an input from at least one of the plurality of sense electrodes, the attenuator being included in a sensing channel of a capacitive sensor; and a signal generator coupled to an input of the attenuator, the signal generator comprising one or more processors configured to: generate a sinusoidal signal based, at least in part, on one or more noise characteristics of a scan sequence associated with one or more transmit electrodes of the capacitive sensing device; provide the sinusoidal signal to the input of the attenuator; a controller configured to implement the scan sequence and obtain a plurality of measurements based on the scan sequence; and wherein the device further comprises: a mixer configured to combine the sinusoidal signal received from the signal generator and the input received from the at least one of the plurality of sense electrodes, and further configured to generate an output based on the combining. ### Claim 15 (depends on 14) The system of claim 14, wherein the signal generator comprises a sinusoidal modulator. ### Claim 16 (depends on 14) The system of claim 14, wherein the signal generator is configured to use the sinusoidal signal to modulate a gain of the attenuator. ### Claim 17 (depends on 14) The system of claim 14, wherein the signal generator is configured to provide the sinusoidal signal to the attenuator during the scan sequence.