Pulse Wave Propagation Time Calculation Device with Peak Shift Correction

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Solution Overview

Problem

Existing pulse wave propagation time measurement devices face challenges in achieving precise measurements due to peak shifts caused by filtering, particularly because electrocardiographic and photoelectric pulse wave signals have different frequency components, leading to reduced precision in calculating pulse wave propagation time.

Innovation Solution

A pulse wave propagation time measurement device is designed with an electrocardiographic sensor and a photoelectric pulse wave sensor, incorporating signal processing means for filtering and peak detection, along with a correcting mechanism that adjusts for delay times based on frequency components to accurately specify peaks and calculate pulse wave propagation time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If filtering processing is performed on electrocardiographic and photoelectric pulse wave signals, then signal-to-noise ratio is improved, but peak positions are shifted reducing measurement precision

Engineering Contradiction:
Improvesignal-to-noise ratioVSAvoidpeak detection precision
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent applies preliminary action by performing filtering processing on the electrocardiographic and photoelectric pulse wave signals before peak detection. This advance filtering improves the signal-to-noise ratio of the input signals, creating a cleaner signal foundation for subsequent peak detection, thereby resolving the contradiction between noise reduction and measurement precision.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent applies parameter changes by dynamically adjusting the delay time correction values based on the detected frequency components of the signals. The correction values are modified according to frequency variations, allowing the system to compensate for filter-induced peak shifts adaptively, thus maintaining measurement precision while benefiting from filtering.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If frequency-dependent filters are used to process signals with different frequency components, then signal quality is improved, but differential peak shifts occur between electrocardiographic and photoelectric pulse wave signals

Engineering Contradiction:
Improvesignal qualityVSAvoidpulse wave propagation time measurement precision
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent applies feedback by detecting the frequency components of the filtered signals and using this information to adjust the delay time correction values. This feedback loop allows the system to compensate for the differential peak shifts caused by frequency-dependent filtering, maintaining accurate pulse wave propagation time measurements while preserving signal quality improvements.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent applies parameter changes by modifying the delay time correction parameters based on the detected frequency components. When frequency variations are detected, the correction values are adjusted accordingly, enabling the system to adapt to different signal conditions and compensate for differential shifts between the two signal types.

Inventive Principle:
Principle #35Parameter changes

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

This approach improves the signal-to-noise ratio and allows for more precise measurement of pulse wave propagation time by correcting for peak shifts, even with frequency-dependent filters, ensuring accurate detection of peaks and calculation of pulse wave propagation time.

Implementation Method 1

an electrocardiographic sensor 10 having electrocardiographic electrodes 11, 12 and detecting an electrocardiographic signal

Methodology Applied
Scientific EffectElectrocardiographic potential detection: Electrical Impedance Tomography

Implementation Method 2

a photoelectric pulse wave sensor 20 having a light-emitting element 21 and a light-receiving element 22 and detecting a photoelectric pulse wave signal

Methodology Applied
Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentEP2962633B1Pulse wave propagation time calculation device
Publication Date: 2020.03.04 MURATA MFG CO LTD
  • EP2962633B1 patent drawingFigure 1
  • EP2962633B1 patent drawingFigure 2
  • EP2962633B1 patent drawingFigure 3

AI summary

A pulse wave propagation time measurement device (1) includes a first signal processing section (310) configured to perform filtering processing on an electrocardiographic signal detected by an electrocardiographic sensor (10), a second signal processing section (320) configured to perform filtering processing on a photoelectric pulse wave signal detected by a photoelectric pulse wave sensor (20), peak detectors (316, 326) respectively configured to detect peaks of the electrocardiographic signal and the photoelectric pulse wave signal, delay time obtaining sections (317, 327) respectively configured to obtain a delay time of the electrocardiographic signal in the first signal processing section (310) and a delay time of the photoelectric pulse wave signal in the second signal processing section (320), peak correctors (318, 328) respectively configured to correct the peak of the electrocardiographic signal and the peak of the photoelectric pulse wave signal based on the delay time of the electrocardiographic signal and the delay time of the photoelectric pulse wave signal, and a pulse wave propagation time measurement section (330) configured to obtain a pulse wave propagation time from a time difference between the peak of the electrocardiographic signal and the peak of the photoelectric pulse wave signal which have been corrected.