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M. Mukunda Rao
may produce a complex motion artefact, just as ambient light can also cause artefacts by coupling to probe receiver, either directly or by transmission through the
tissue. Whilst it is theoretically possible by straightforward means to remove ambient
artefact, practical limitations mean that sufficiently bright or high frequency artificial light sources can still cause artefacts. Thus it is imperative that the investigations/measurements should be conducted under controlled conditions. A normal PPG
signal free from artefacts is shown in Fig. 2.4. Figures 2.5 and 2.6 show the breathing
signal and ECG signal recorded under normal breathing conditions.
A special equipment which was designed and built for this study called Universes
II by Mr. K. H. Strotmann, Germany, for simultaneous recording of all the above
parameters namely PPG, Breathing & ECG was used for the present investigation.
Fig. 2.4 Typical PPG signal free of any artefact
Fig. 2.5 Typical breathing signal free of any artefact
Fig. 2.6 Typical ECG signal free from any artefact
M. Mukunda Rao
may produce a complex motion artefact, just as ambient light can also cause artefacts by coupling to probe receiver, either directly or by transmission through the
tissue. Whilst it is theoretically possible by straightforward means to remove ambient
artefact, practical limitations mean that sufficiently bright or high frequency artificial light sources can still cause artefacts. Thus it is imperative that the investigations/measurements should be conducted under controlled conditions. A normal PPG
signal free from artefacts is shown in Fig. 2.4. Figures 2.5 and 2.6 show the breathing
signal and ECG signal recorded under normal breathing conditions.
A special equipment which was designed and built for this study called Universes
II by Mr. K. H. Strotmann, Germany, for simultaneous recording of all the above
parameters namely PPG, Breathing & ECG was used for the present investigation.
Fig. 2.4 Typical PPG signal free of any artefact
Fig. 2.5 Typical breathing signal free of any artefact
Fig. 2.6 Typical ECG signal free from any artefact