Blood Pressure Measurement via Vibration Signal Filtering
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Solution Overview
Problem
Traditional non-invasive blood pressure measurement techniques rely on subjective listening to Korotkoff sounds, which are prone to external noise interference, leading to inaccurate systolic and diastolic pressure determination.
Innovation Solution
A device and method that utilize a signal conversion circuit and processor to filter out noise from vibration signals, converting them into digital signals and determining systolic and diastolic pressure points, using a Wheatstone bridge, differential signal amplifier, low-pass filter, and analog-to-digital converter, with a finite impulse response digital filter to isolate the principal component wave.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional listening methods are used to detect Korotkoff sounds, then the measurement process is simple, but the accuracy is reduced due to external noise interference
Solution Approach 1:
The patent introduces vibration sensors as an intermediary device to detect Korotkoff sounds indirectly through body surface vibration, rather than direct listening. This intermediary approach isolates the measurement from external noise sources while capturing the essential physiological signal for accurate blood pressure determination
Solution Approach 2:
The patent replaces the acoustic listening system (stethoscope/microphone) with a vibration sensing system that measures mechanical vibrations of the body surface. This substitution transforms the detection method from acoustic to mechanical domain, effectively eliminating external noise interference while preserving Korotkoff sound detection capability
2Measurement precision
If vibration sensors are used to measure body surface vibration, then external noise interference is reduced, but signal noise remains in the waveform
Solution Approach 1:
The patent extracts the principal component wave from the noisy vibration signal through spectral analysis and filtering operations. By separating the desired Korotkoff sound signal from the noise components in the frequency domain, the system achieves clear waveform identification for accurate systolic and diastolic pressure determination
Solution Approach 2:
The patent transforms the vibration signal from time domain to frequency domain through Fourier transform, enabling parameter-based filtering. By identifying and removing frequency components outside the Korotkoff sound range, the system eliminates signal noise while preserving the essential measurement information
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 reduces noise interference, improving the accuracy of blood pressure measurement and subsequent cardiovascular condition evaluation by isolating the principal component wave corresponding to Korotkoff sounds.
Implementation Method 1
measuring a target area and generating a vibration signal by the vibration sensor
Implementation Method 2
The signal conversion circuit may comprise three resistors, the three resistors constitute a Wheatstone bridge with the vibration sensor
Implementation Method 3
The signal conversion circuit further comprises a low-pass filter electrically connected with the differential signal amplifier
Data Source
AI summary
A device for measuring blood pressure receives a vibration signal from a vibration sensor which is used to measure a target area. The device then converts the vibration signal into a digital signal and performs a filtering process on the digital signal. The filtering process involves removing noise around the principal component wave that corresponds to the pulsation of the target area within a specific range in the digital signal. Subsequently, based on the digital signal that has been filtered, the device determines a systolic pressure determination time point and a diastolic pressure determination time point to generate a blood pressure measurement result.