Biomedical Instrumentation (concepts)

Question 1

Measurand

Answer 1

physical quantity measured by the instrument

Question 2

Sensor

Answer 2

a device that converts measurand to electrical signals
- should only respond to the form of energy in the measurand
-should be minimally invasive

Question 3

Signal conditioning

Answer 3

-allows for clearer and more accurate measurements
-amplification, filtering, digitizing, processing
-not directly coupled to the display device

Question 4

Output display

Answer 4

numerical, graphical discrete, continuous

Question 5

auxiliary elements

Answer 5

calibration, control, and feedback

Question 6

Constraints of biomedical measurement

Answer 6

-low magnitude of biological signals
-access constraint (invasive or non-invasive)
-stochastic physical quantity
-saftey issues

Question 7

stochastic quantity

Answer 7

approximation value or randomly determined

Question 8

Any measurement includes:

Answer 8

-signal and noise

Question 9

signal in a measurement

Answer 9

-ECG
-Blood pressure
-temperature

Question 10

Extrenal noise in a measurement

Answer 10

60Hz, radio frequency, magnetic

Question 11

Internal noise in a measurement

Answer 11

muscle noise, motion artifact (heart beating, breathing)

Question 12

Signal filtering

Answer 12

can seperate noise form desired signal using ther distinct property
(seperate high frequency from low)

Question 13

Analog filters

Answer 13

have the property of removing unwanted frequencies from our signal
(Are small circuits)

Question 14

What is noise?

Answer 14

is everything we collect that we do not want to remeber

Question 15

Main sources of noise in ECG are:

Answer 15

low frequency:
- muscle tremor
-respiration
60Hz

Question 16

Analog signal

Answer 16

a continous electrical signal

Question 17

Digital signal

Answer 17

only recorded at certain values

Question 18

Fourier transform

Answer 18

time-domain can be the average of 2 intervals and can be seperated into the 2 graphs that make the average
- can then be transformed into a frequency domain graph

Question 19

time-domain graph

Answer 19

shows how a signal changes over time

Question 20

frequency-domain graph

Answer 20

shows how much of the signal lies within each given frequency band over a range

Question 21

low-pass filters

Answer 21

filters out high frequencies, allows low frequencies

Question 22

high-pass filters

Answer 22

removes low-frequencies, allows high frequencies

Question 23

band-pass filters

Answer 23

allows frequencies within a specific range to pass, blocks frequencies outside of that range

Question 24

Notch filter

Answer 24

weakends frequencies within a narrow range, allows other frequencies to pass

Question 25

operational amplifiers

Answer 25

needed to amplify, enhance the very small signals that we measure -convert to digital form

Question 26

current

Answer 26

electrical current is a flow of electrical chrage through a conductive medium -passes electrically through wires

Question 27

Current equation

Answer 27

I = Q/ t

Question 28

Voltage

Answer 28

difference in the amount of electrical potential between 2 points (in a circuit or electrical field)

Question 29

Higher voltage = _______ current

Answer 29

higher current

Question 30

Voltage that does not change over time

Answer 30

DC constant voltage (V)

Question 31

Voltage that changes over time

Answer 31

AC time-varying voltage v(t)

Question 32

Resistance

Answer 32

a circuit element that limits the flow of current through it

Question 33

Resistance, current, and voltage

Answer 33

V = I R

Question 34

Capacitor

Answer 34

stores charge, made up of 2 metal plates seperated by a non-conducting material (often air) DIELECTRIC- seperation between

Question 35

How does a capacitor work?

Answer 35

-charges cant easily flow between the plates -electrosn will start to jump the small distance bewteen plates when the negative + positive sides store enough charge (no direct charge)

Question 36

Difference between capacitors and batteries?

Answer 36

Capacitors are able to dispose of all of their charge very quickly - batteries are more susutainable charge

Question 37

Capacitance equation

Answer 37

C = Q/ /\V

Question 38

Q in equations

Answer 38

electrical charge

Question 39

LPF diagram

Answer 39

Resistor is first, capacitor is second

Question 40

HPF diagram

Answer 40

Capacitor is first, resistor is second