Sensor Data Correction Using On-Chip Interpolation
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Solution Overview
Problem
Inaccuracies in sensor data sampling due to manufacturing variability and temperature variations, which are not effectively addressed by existing methods without increasing power consumption, especially when using external host processors or high-frequency phase locked loops.
Innovation Solution
Incorporating a low power interpolator circuit within the sensor chip to correct data inaccuracies using a reference clock signal, allowing for interpolation of sampled values and reducing power consumption by performing corrections within the sensor chip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a host processor external to the sensor chip is used to correct sampling inaccuracies, then measurement precision is improved, but power consumption increases
Solution Approach 1:
The correction function is extracted from the external host processor and implemented as dedicated interpolator circuitry within the sensor chip itself. This allows the correction operation to be performed locally with minimal power consumption while maintaining high sampling accuracy through specialized hardware designed solely for this purpose.
Solution Approach 2:
An interpolator circuit acts as an intermediary between the sampling unit and the host processor. This intermediary performs the correction function using a low-power reference clock signal, eliminating the need for the host processor to perform power-intensive correction operations while still delivering accurate corrected samples.
2Measurement precision
If a high frequency phase locked loop is used to correct sampling inaccuracies, then measurement precision is improved, but power consumption increases
Solution Approach 1:
The system changes the clock frequency parameter by using a low-frequency reference clock signal (e.g., 32.768 kHz) instead of a high-frequency clock signal. This parameter change enables accurate interpolation and correction of sampling errors while consuming significantly less power, as lower frequency oscillators require less energy to operate.
3Measurement precision
If correction operations are performed externally by a host processor, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The interpolator circuit is merged with the sensor chip, integrating the correction function directly into the sensing device. This consolidation eliminates the need for complex external correction processing by the host processor, reducing overall system complexity while maintaining high sampling accuracy through dedicated on-chip correction circuitry.
Data Source
AI summary
A device may include a sensor, a sampling unit, and an interpolator. The sensor may be configured to sense motion and output a sensed signal. The sampling unit may be configured to sample the sensed signal with a sensor clocking signal to generate a plurality of sampled values. The interpolator may be coupled to the sampling unit and may be configured to receive the plurality of sampled values, the sensor clocking signal, and a reference clocking signal external to the device. The interpolator may be configured to interpolate the plurality of sampled values based on the reference clocking signal and further based on the sensor clocking signal to generate a plurality of output values.