Sleep Signal Conditioning Device for Clipped Sensor Signals
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Solution Overview
Problem
Sleep signal conditioning devices face challenges in capturing both low amplitude physiological signals and high amplitude movement signals due to the large dynamic range required, often resulting in signal clipping that prevents accurate assessment of motion intensity.
Innovation Solution
A sleep signal conditioning device and method that utilize multiple sensors to estimate clipped signals by calculating a ratio based on the magnitude of non-clipped signal portions, allowing for the generation of an estimated signal that restores the original dynamic range, thereby providing accurate physiological and movement signals during sleep.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If adjustable attenuation is applied to the sensor signal to enable measuring both small and large amplitude signals, then the dynamic range is extended, but the measurement precision of the physiological signals deteriorates due to signal clipping
Solution Approach 1:
The patent segments the sensor signal processing into multiple channels with different attenuation levels. Instead of applying a single attenuation level to all signals, the system divides the signal processing into multiple pathways, each handling different amplitude ranges, thereby preventing clipping while maintaining precision across the full dynamic range
Solution Approach 2:
The patent dynamically changes the attenuation parameter based on the signal amplitude. By adjusting the attenuation level according to the detected signal strength, the system maintains optimal measurement precision across varying signal conditions while extending the effective dynamic range of the monitoring system
2Adaptability or versatility
If a large dynamic range is required to capture both low amplitude physiological signals and high amplitude movement signals, then both signal types can be detected, but signal clipping occurs that prevents accurate assessment of motion intensity
Solution Approach 1:
The patent segments the monitoring function into specialized channels: one optimized for physiological signals and another for movement signals. This segmentation allows each channel to operate within its optimal range without clipping, preserving motion intensity information that would otherwise be lost in a single-channel system
Solution Approach 2:
The patent introduces an intermediary processing stage that detects clipping conditions and compensates for lost information. When clipping is detected in the movement signal channel, the system uses intermediate calculations and alternative signal paths to recover motion intensity data that would otherwise be permanently lost
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively mitigates signal clipping by estimating energy from non-clipped signal portions, providing a proportional and accurate output signal that captures both physiological and movement data without the need for complex logarithmic sensors, thus enhancing sleep monitoring accuracy.
Implementation Method 1
It is known that piezoelectric sensors positioned under a mattress are suitable for extracting physiological signals
Data Source
AI summary
A method and device are provided for conditioning a sleep signal from a sleep sensor for a sleep monitor. A sleep sensor is configured to sense a physiological signal, such as a cardiac or respiratory signal from a sleeping mammal, such as a human, e.g. an infant or a baby. If the mammal exhibits also (gross) body movement during his sleep, the sensor signal may be clipped. The method and device provide a conditioning of the sleep signal by providing an estimation of the sleep signal instead of the conditioned sleep signal itself when the sensor signal is clipping.