Biomedical Instrumentation

Basic block diagram of Biomedical instrumentation

1. Biomedical Transducer
Ms. Dixita Dhobi, Lecturer
Biomedical Engineering

2. Introduction to Biomedical Instrumentation
CHAPTER-1

3. Introduction
•Biomedicalinstrumentationistheapplicationofbiomedical
engineeringwhichismainlyfocusonthedevicesand
mechanicswhichisusedtomeasureandevaluatesome
physicalquantity.Themainpurposeofthebiomedical
instrumentationisusedtomeasurethepresenceofsome
physicalquantity.
•Itisthebranchwhichdealswiththeuseofinstrumentsto
measureandcontrolvariables.

4. Basic Bio instrumentation system
The basic Bio instrumentation system consists of the following
components,
•Subject (human body as a input)
•Primary Sensing device
•Transducer
•Signal processing unit
•Terminating stage (Display, Recorder, Controller and Computer)

5. Block diagram of Bio-instrumentation system
PRIMARY
SENSING
DEVICE
TRANSDUCER
SIGNAL
PROCESSING
UNIT
DISPLA
Y
RECOR
DER
CONTRO
LLER
COMPU
TER
TERMINATING STAGE
I/P

6. Description
Subject(Input)
•Thesubjectisthehumanbeingonwhomthemeasurements
aremade.
Primarysensingdevice
•Primarysensingdeviceisattachedtothehumanbody,which
isusedtosensesomephysicalquantityliketemperature,
pressureetcandthentransmitintotransducer.

7. Continue…
Transducer
•Transducerisadevice,whichisconnecttotheprimary
sensingdevice.Transducerreceivesomephysicalquantity
fromtheprimarysensingdevice.
•Thentransducerconvertsnon-electricalquantity/physical
quantityintoelectricalquantity.

8. Signal conditioning equipment
•Thepartoftheinstrumentationsystemthatamplifies,modifies
orinanyotherwaychangetheelectricoutputofthetransduceris
calledsignalconditioningorsignalprocessingdevice/equipment.
•Signalconditioningequipmentusuallyconsistsoffunctionssuch
asfiltering(digitaloranalog),amplification,Demodulation,
A/DconverterandD/Aconverter.
•Theyhelpinincreasingthesensitivityofdevicebyamplification
oftheoriginalsignal.Andfilterisusedtoremoveunwantednoise
andfrequencyformsignalandprovideaccurateoutput.

9. Continue…Displaysystem
•Theelectricaloutputofthesignalconditioningequipment
mustbeconvertedintoaformthatcanbeperceivedbyone
oftheman’ssensesthatcanconveytheinformationobtained
bythemeasurementinameaningfulway.
•Thedisplaysystemprovidesavisiblerepresentationofthe
quantityasaanalogordigitalform.

10. Continue…
Recording,ControllerandComputer
•Itisnecessarytorecordthemeasuredinformationorto
transmititfromonelocationtoanotherlocation.
•Forthispurposethiscomponentisrequired.
•Acontroldeviceisusedtohavetoanautomaticcontrolof
thestimulus,transducers,signalprocessingunitorany
otherpartofthe‘Bioinstrumentationsystem’.
•Wholesystemisconnectedtothecomputer.Itisnecessary
torecordtheoutputandtotransmititfromonelocationto
anotherlocation.