Physical Quantity Detection Circuit With Digital Noise Filtering
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Solution Overview
Problem
Existing physical quantity sensor devices face challenges in detecting digital and analog sensor signals with high precision due to noise components, making it difficult to obtain accurate digital physical quantity signals.
Innovation Solution
A physical quantity detection circuit that includes an analog-to-digital converter, a digital filter to attenuate high-frequency noise, a multiplier circuit, and optional down-sampling and interpolation filters to improve signal precision, with adjustable tap coefficients for phase correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If digital detection is performed on the sensor signal without prior noise attenuation, then the detection processing can be executed, but the detection precision of the digital physical quantity signal deteriorates due to noise components
Solution Approach 1:
The patent applies preliminary action by performing noise attenuation through digital filtering before the detection processing is executed. The sensor signal is converted to digital form and filtered to remove noise components at high frequencies prior to the multiplication operation that detects the physical quantity. This preliminary noise removal ensures that the subsequent detection processing operates on clean signal data, thereby improving detection precision without being degraded by noise.
2Measurement precision
If over-sampling is performed to improve signal precision, then the signal-to-noise ratio improves, but the processing burden and storage requirements increase
Solution Approach 1:
The patent applies the taking out principle by extracting and removing the noise frequency components from the over-sampled digital sensor signal through digital filtering. After over-sampling converts the analog sensor signal to digital form with improved signal-to-noise ratio, the digital filter extracts and eliminates the harmful high-frequency noise components while preserving the useful signal components. This extraction of noise allows the system to maintain high signal precision while reducing the processing burden compared to handling all frequency components including noise.
3Measurement precision
If a digital filter with adjustable tap coefficients is used to attenuate noise, then the detection accuracy improves, but the device complexity increases
Solution Approach 1:
The patent applies parameter changes by using a digital filter with adjustable tap coefficients that can be optimized for different detection scenarios. The tap coefficients are configurable parameters that control the filtering characteristics of the digital filter. By adjusting these parameters, the system can optimize noise attenuation performance for different physical quantity detection applications while managing circuit complexity through parameter optimization rather than hardware redesign.
Data Source
AI summary
A physical quantity detection circuit (12) is used for a physical quantity sensor (10) that outputs a sensor signal according to a physical quantity given externally. In the physical quantity detection circuit (12), an analog-to-digital converter (104) converts an analog sensor signal (Ssnc) to a digital sensor signal (Dsnc). A digital filter (100) attenuates a frequency component of the digital sensor signal (Dsnc) that is higher than a predetermined cutoff frequency. A multiplier (106) multiplies a digital sensor signal (Dps) having passed the digital filter (100) by a digital detection signal (Ddet) to detect a digital physical quantity signal (Dphy).