Methods and systems for determining a noise-robust acquisition configuration for operating a sensor system
Systems and methods of determining a noise-robust acquisition configuration for a sensor or communication system are disclosed. An exemplary method comprises a noise scan with: obtaining a sensor receive signal from the sensor system; determining a digital receive signal from the sensor receive signal by A/D conversion of the sensor receive signal at a predefined noise scan frequency; determining a plurality of decimated digital receive signals by integer decimation of the digital receive signal using two or more decimation rates that differ from each other, wherein each of the two or more decimation rates is associated with a respective candidate acquisition configuration; determining one or more noise measures for multiple of the candidate acquisition configurations using one or more of the plurality of decimated digital receive signals; and using the one or more noise measures, determining the acquisition configuration for operation of the sensor system from the candidate acquisition configurations.
1. A method of determining a noise-robust acquisition configuration for operation of a sensor system, comprising performing a noise scan, the noise scan comprising:
obtaining a sensor receive signal from the sensor system without a stimulus signal being applied to the sensor system;
determining a digital sensor receive signal from the sensor receive signal by A/D conversion of the sensor receive signal at a predefined noise scan frequency;
determining a plurality of decimated digital sensor receive signals by integer decimation of the digital sensor receive signal using two or more decimation rates that differ from each other, wherein respective ones of the two or more decimation rates are associated with a respective candidate acquisition configuration for the sensor system;
in response to determining the plurality of decimated digital sensor receive signals, determining one or more noise measures for multiple candidate acquisition configurations by evaluating one or more of the plurality of decimated digital sensor receive signals; and
using the one or more noise measures, determining the acquisition configuration for operation of the sensor system from the multiple candidate acquisition configurations; wherein
determining the acquisition configuration comprises selecting a preferred noise measure from the one or more noise measures and selecting a first candidate acquisition configuration of the candidate acquisition configurations, which first candidate acquisition configuration is associated with the preferred noise measure as the acquisition configuration.
2. The method of claim 1 , wherein the preferred noise measure yields the lowest noise level of the one or more noise measures.
3. The method of claim 1 , wherein for respective ones of the two or more decimation rates, corresponding groups of decimated digital sensor receive signals are determined, wherein in each group, the decimated digital sensor receive signals differ from each other in a different starting phase.
4. The method of claim 3 , wherein one or more of the noise measures are determined by an effective noise power estimation, which comprises a determination of a sum of phase-instantaneous noise measures over the respective decimated digital sensor receive signals of one of the groups of decimated digital sensor receive signals.
5. The method of claim 4 , wherein the phase-instantaneous noise measure is a sum of samples of a decimated digital sensor receive signal weighted with coefficients from a coefficient vector.
6. The method of claim 1 , wherein the acquisition configuration comprises at least one or more of a sampling frequency for A/D conversion, an operating frequency of a stimulus signal for operation of the sensor system, a scan duration, a number of samples to be acquired, and low-pass filter coefficients.
7. The method of claim 1 , wherein the predetermined noise scan frequency is significantly higher than an operating frequency of a stimulus signal during operation of the sensor system.
8. The method of claim 1 , wherein the two or more decimation rates are multiples of 2.
9. The method of claim 1 , wherein the sensor receive signal during the noise scan is acquired without a stimulus signal being applied to the sensor system.
10. The method of claim 1 , wherein determining the acquisition configuration for operation of the sensor system from the candidate acquisition configurations comprises comparing the one or more noise measures with a noise threshold and in case the noise threshold is not met by any of the noise measures:
increasing a scan time of at least one of the candidate acquisition configurations to obtain at least one updated candidate acquisition configuration;
determining one or more updated noise measures for the at least one updated candidate acquisition configuration; and
comparing the one or more updated noise measures with the noise threshold.
11. The method of claim 10 , wherein the increased scan time is an integer multiple of a scan time of a preceding noise scan.
12. The method of claim 1 , comprising following the noise scan, operating the sensor system during a signal-and-noise scan using the acquisition configuration determined during the noise scan.
13. The method of claim 12 , comprising subsequently conducting multiple noise scans between two signal-and-noise scans, wherein the multiple noise scans use predefined noise scan frequencies, wherein the predefined noise scan frequencies of at least some of the multiple noise scans differ from each other.
14. The method of claim 13 , comprising determining an overall acquisition configuration for operation of the sensor system during a signal-and-noise scan from acquisition configurations obtained during the subsequently conducted multiple noise scans.
15. The method of claim 12 , wherein an aperture time of an A/D conversion during the noise scan is identical to, or substantially an integer fraction of, an aperture time set for the signal-and-noise scan.
16. The method of claim 1 , wherein the sensor system is one or more of a capacitive sensor system and a touchscreen sensor system.
17. A non-transitory computer-readable medium including contents that are configured to cause a sensor circuit to conduct the method of claim 1 .
18. A sensor circuit to determine an acquisition configuration for operation of a sensor system, comprising:
a sensor interface for obtaining a sensor receive signal from the sensor system without a stimulus signal being applied to the sensor system;
an A/D converter to determine a digital sensor receive signal from the sensor receive signal by A/D conversion of the sensor receive signal at a predefined noise scan frequency;
a decimation circuit, to determine a plurality of decimated digital sensor receive signals by integer decimation of the digital sensor receive signal using two or more decimation rates that differ from each other, wherein respective ones of the two or more decimation rates are associated with a respective one of multiple candidate acquisition configurations for the sensor system;
a noise evaluation circuit, to, in response to determining the plurality of decimated digital sensor receive signals, determine one or more noise measures for multiple candidate acquisition configurations by evaluating one or more of the plurality of decimated digital receive signals; and
a configuration circuit, to determine the acquisition configuration for operation of the sensor system from the multiple candidate acquisition configurations using the one or more noise measures; wherein
determining the acquisition configuration comprises selecting a preferred noise measure from the one or more noise measures and selecting a first candidate acquisition configuration of the candidate acquisition configurations, which first candidate acquisition configuration is associated with the preferred noise measure as the acquisition configuration.
19. A capacitive touch sensing system, comprising:
one or more electrodes, configured for capacitive sensing; and
the sensor circuit of claim 18 , which sensor circuit is connected to at least one of the one or more electrodes.
20. A method of determining a noise-robust acquisition configuration for operation of a communication system, comprising performing a noise scan, the noise scan comprising:
obtaining a receive signal from the communication system without a stimulus signal being applied to the communication system;
determining a digital receive signal from the receive signal by A/D conversion of the receive signal at a predefined noise scan frequency;
determining a plurality of decimated digital receive signals by integer decimation of the digital receive signal using two or more decimation rates that differ from each other, wherein respective ones of the two or more decimation rates are associated with a respective one of multiple candidate acquisition configurations for the communication system;
in response to determining the plurality of decimated digital receive signals, determining one or more noise measures for multiple candidate acquisition configurations by evaluating one or more of the plurality of decimated digital receive signals; and
using the one or more noise measures, determining the acquisition configuration for operation of the communication system from the multiple candidate acquisition configurations; wherein
determining the acquisition configuration comprises selecting a preferred noise measure from the one or more noise measures and selecting a first candidate acquisition configuration of the candidate acquisition configurations, which first candidate acquisition configuration is associated with the preferred noise measure as the acquisition configuration.
21. A communication circuit to determine an acquisition configuration for operation of a communication system, comprising:
a communication system interface to obtain a receive signal from the communication system without a stimulus signal being applied to the communication system;
an A/D converter to determine a digital receive signal from the receive signal by A/D conversion of the receive signal at a predefined noise scan frequency;
a decimation circuit, to determine a plurality of decimated digital receive signals by integer decimation of the digital receive signal using two or more decimation rates that differ from each other, wherein respective ones of the two or more decimation rates are associated with a respective one of multiple candidate acquisition configuration for the communication system;
a noise evaluation circuit, to, in response to determining the plurality of decimated digital receive signals, determine one or more noise measures for multiple candidate acquisitions configuration by evaluating one or more of the plurality of decimated digital receive signals; and
a configuration circuit, to determine the acquisition configuration for operation of the communication system from the multiple candidate acquisition configurations using the one or more noise measures; wherein
determining the acquisition configuration comprises selecting a preferred noise measure from the one or more noise measures and selecting a first candidate acquisition configuration of the candidate acquisition configurations, which first candidate acquisition configuration is associated with the preferred noise measure as the acquisition configuration.
22. A method of determining a noise-robust acquisition configuration for operation of a sensor system, comprising performing a noise scan, the noise scan comprising:
obtaining a sensor receive signal from the sensor system without a stimulus signal being applied to the sensor system;
determining a digital sensor receive signal from the sensor receive signal by A/D conversion of the sensor receive signal at a predefined noise scan frequency;
determining a plurality of decimated digital sensor receive signals by integer decimation of the digital sensor receive signal using two or more decimation rates that differ from each other, wherein respective ones of the two or more decimation rates are associated with a respective candidate acquisition configuration for the sensor system;
in response to determining the plurality of decimated digital sensor receive signals, determining one or more noise measures for multiple candidate acquisition configurations by evaluating one or more of the plurality of decimated digital sensor receive signals; and
using the one or more noise measures, determining the acquisition configuration for operation of the sensor system from the multiple candidate acquisition configurations; wherein
determining the acquisition configuration for operation of the sensor system from the candidate acquisition configurations comprises comparing the one or more noise measures with a noise threshold and in case the noise threshold is not met by any of the noise measures:
increasing a scan time of at least one of the candidate acquisition configurations to obtain at least one updated candidate acquisition configuration;
determining one or more updated noise measures for the at least one updated candidate acquisition configuration; and
comparing the one or more updated noise measures with the noise threshold.
23. A non-transitory computer-readable medium including contents that are configured to cause a sensor circuit to conduct the method of claim 22 .
24. A sensor circuit to determine an acquisition configuration for operation of a sensor system, comprising:
a sensor interface for obtaining a sensor receive signal from the sensor system without a stimulus signal being applied to the sensor system;
an A/D converter to determine a digital sensor receive signal from the sensor receive signal by A/D conversion of the sensor receive signal at a predefined noise scan frequency;
a decimation circuit, to determine a plurality of decimated digital sensor receive signals by integer decimation of the digital sensor receive signal using two or more decimation rates that differ from each other, wherein respective ones of the two or more decimation rates are associated with a respective one of multiple candidate acquisition configurations for the sensor system;
a noise evaluation circuit, to, in response to determining the plurality of decimated digital sensor receive signals, determine one or more noise measures for multiple candidate acquisition configurations by evaluating one or more of the plurality of decimated digital receive signals; and
a configuration circuit, to determine the acquisition configuration for operation of the sensor system from the multiple candidate acquisition configurations using the one or more noise measures; wherein
determining the acquisition configuration for operation of the sensor system from the candidate acquisition configurations comprises comparing the one or more noise measures with a noise threshold and in case the noise threshold is not met by any of the noise measures:
increasing a scan time of at least one of the candidate acquisition configurations to obtain at least one updated candidate acquisition configuration;
determining one or more updated noise measures for the at least one updated candidate acquisition configuration; and
comparing the one or more updated noise measures with the noise threshold.
25. A capacitive touch sensing system, comprising:
one or more electrodes, configured for capacitive sensing; and
the sensor circuit of claim 24 , which sensor circuit is connected to at least one of the one or more electrodes.