Method and apparatus for digital demodulation and further processing of signals obtained in the measurement of electrical bioimpedance or bioadmittance in an object

Inactive Publication Date: 2007-02-22
OSYPKA MEDICAL
View PDF76 Cites 99 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0025] With the sampling rate being significantly higher than the highest frequency component of the excitation signal, particularly an alternating current (AC), applied, the method and apparatus according to the invention provides measurement results at not only a sufficient resolution but a very high amplitude resolution. Unlike common approaches proposed for the display of multi-frequency bioimpedance (Withers P.O.: U.S. Pat. No. 5,280,429) and in a real-time electrical impedance tomography system (Brown B. H. and Barber D. C.: U.S. Pat. No. 5,311,878), bioimpedance or bioadmittance cardiometry requires a high resolution and accur

Problems solved by technology

However, conventional demodulation by diodes and subsequent low-pass filtering exhibit certain drawbacks.
Moreover, even a full-wave rectified sinusoidal signal is difficult to smooth; the time constant of the smoothing low-pass filter cannot be chosen appropriately high because the bandwidth of the desired demodulated signal will be limited, and critical waveform detail can be lost.
Digitization of a signal with rippl

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Method and apparatus for digital demodulation and further processing of signals obtained in the measurement of electrical bioimpedance or bioadmittance in an object
  • Method and apparatus for digital demodulation and further processing of signals obtained in the measurement of electrical bioimpedance or bioadmittance in an object
  • Method and apparatus for digital demodulation and further processing of signals obtained in the measurement of electrical bioimpedance or bioadmittance in an object

Examples

Experimental program
Comparison scheme
Effect test

Example

[0135] According to a first embodiment, FIG. 4a and 4b, the voltage controlled current source (VCCS) 42, which generates a single frequency (SF) or multi-frequency (MF) alternating current (AC), and the differential amplifier (A) 50 are switched to the calibration impedance 20, and the alternating current (AC) applied and the resulting voltage are measured, amplified and digitized.

[0136] In the event of a single frequency (SF) alternating current (AC) application, because the frequency of the measured alternating current (AC) applied and, thus, of the voltage measured is known, the samples measured, amplified and digitized can be fitted towards discrete values of an ideal sinusoidal waveform using commonly known fitting processes.

[0137] Then, in a process further referred to as indirect correlation, for each frequency fAC of the alternating current (AC) applied, the amplified, digitized and optionally fitted samples obtained from the measurement of the alternating current (AC) app...

Example

[0141] According to a second embodiment, FIG. 5, the voltage controlled current source (VCCS) 42, which generates a single-frequency (SF) alternating current (AC), and the differential amplifier (A) 50 are switched to the calibration impedance 20, and the alternating current (AC) applied and the resulting voltage are measured, amplified and digitized.

[0142] Because the frequency of the alternating current (AC) applied and, thus, of the voltage measured is known, the samples obtained, amplified and digitized can be fitted towards discrete values of an ideal sinusoidal waveform using commonly known fitting processes.

[0143] Then, in a process further referred to as direct correlation, the amplified, digitized and optionally fitted samples obtained from the measurement of the voltage and obtained from the measurement of the alternating current (AC) applied are correlated.

[0144] Thereafter, the aforementioned processes are performed with the current source (VCCS) 42 and to the differe...

Example

[0146] According to a third embodiment, FIG. 6, the voltage controlled current source (VCCS) 42, which generates a single frequency (SF) or multi-frequency (MF) alternating current (AC), and the differential amplifier (A) 50 are switched to the calibration impedance 20 but only the resulting voltage is measured, amplified and digitized.

[0147] In the event of a single frequency (SF) alternating current (AC) application, because the frequency of the alternating current (AC) applied and, thus, the frequency of the measured voltage is known, the samples obtained, amplified and digitized can be fitted towards discrete values of an ideal sinusoidal waveform using commonly known fitting processes.

[0148] Then, for each frequency fAC of the alternating current (AC) applied, the amplified, digitized and optionally fitted samples obtained from the voltage measurement are correlated with the discrete values of an ideal sine waveform in order to obtain a value proportional to the in-phase port...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

PUM

No PUM Login to view more

Abstract

Methods and apparatus for digital demodulation of signals obtained in the measurement of electrical bioimpedance or bioadmittance of an object. One example comprises: generating an excitation signal of known frequency content; applying the excitation signal to the object; sensing a response signal of the object; sampling and digitizing the response signal to acquire a digitized response signal representing the response signal with respect to frequency content, amplitude and phase; correlating, for each frequency fAC of the excitation signal applied, digitized samples of the response signal, with discrete values representing the excitation signal; calculating, using the correlated signals for each frequency fAC of the excitation signal applied, complex values for the bioimpedance Z(fAC); providing, over time, a set of digital bioimpedance waveforms Z(fAC,t)); separating the base bioimpedance Z0(fAC), from the waveforms; and separating the changes of bioimpedance ΔZ(fAC,t), from the waveforms.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] Priority for this patent application is being claimed to European Patent Application No. EP05017871, filed Aug. 17, 2005, titled “Method and apparatus for digital demodulation and further processing of signals obtained in the measurement of electrical bioimpedance or bioadmittance in an object”, which is incorporated herein by this reference. BACKGROUND [0002] 1. Technical Field [0003] This invention is related to the field of digital demodulation and further processing of signals obtained from the measurement of electrical bioimpedance or bioadmittance in a biological object, for instance an animal or a human due to cardiac and / or respiratory activity, for instance in cardiometry, in particular to the monitoring through measurement of the change in thoracic electrical bioimpedance (TEB) or bioadmittance, and pertains to the processing of the excitation, response and / or reference signals obtained through sensing and measuring excitation...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

Application Information

Patent Timeline
no application Login to view more
IPC IPC(8): A61B5/05
CPCA61B5/0535A61B5/0809A61B5/7239A61B5/7228
Inventor OSYPKA, MARKUSGERSING, EBERHARD
Owner OSYPKA MEDICAL
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Try Eureka
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap