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PHOTOPLETHYSMOGR

APHICCARDIOTACHOMETER

PRESENTED By

A.DHANUJA

M.NAGAVARSHINI

S.PAVITHRA

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OUTLINE

What is photoplethysmographic cardiotachometer ?

Objective

Algorithm

Signal Extraction

Signal conditioning

Peak detector

Overall setup

App Development

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WHAT ISPHOTOPLETHYSMOGRAPHIC

CARDIOTACHOMETER ?  Photoplethysmography !ardiotachometer!ardiotachometer –A heart rate monitor 

Photoplethysmography"

  Photo + PlethysmographyPlethysmography-A measurement technique used

to measure the volume changes in di##erent parts

o# the body$

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OBJECTIVE

To measure heart rate

Why not use stethoscope ?

Why not E!% ?

And why PPG cardiotachometer ?

 

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ALGORITHM :

The Signal from the finger tip

is etracted !y using the principleof photoplethysmographic

transduction "

The signal is then conditioned as

the raw signal from the sensor is

quite wea# and is contaminated

with noise on the top of the $%

component"

Peak Detection using Sliding and

%lim!ing Pea# detection method"

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  SIGNAL EXTRACTIONPRINCIPLE:

Photoplethysmography -

&easures changes in the

volume o# the blood

in the blood vessels !y

the reflection or

transmission of the light

from or through the

tissue "

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WHAT CAUSES CHANGE IN VOLUME OF BLOOD ?

When the 'entricles of the heart

contracts (the volume of the !lood

in the !lood 'essels( mostly in

arteries increases ( there!y the

amount of light absorbed increases

so light re#lected or transmitted

decreases"

When the 'entricles of the heart

relaxes( the volume of the !lood in

the !lood 'essels( mostly in arteries

decreases( the amount o# light

absorbed there!y decreases so light

re#lected or transmitted increases"

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HOW IS ELECTRICAL PULSATION GENERATED ?

The change in the 'olume ofthe !lood within the artery will

directly affect the reflection

from or transmission through

the tissue to !e recei'ed !y the

 photo detector thus generating

an electrical pulsation relatedto plethysmography"

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SIGNAL CONDITIONING

The signal is then conditioned using filters as the raw signal

from the sensor is quite wea# and is contaminated with noiseon the top of the $% component"

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Peak detet!"

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OVERALL SETUP

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