II D digital instrumentation

Question 1

HFF makes muscle artifact look like

Answer 1

Beta

Question 2

evolution

Answer 2

gradual change in 
amplitude
frequency
or spatial distribution of
rhythm

Question 3

60 Hz

Answer 3

Notch filter

Question 4

common mode rejection

Answer 4

ACNS guideline: 90 Db

EEG amplifiers

Question 5

Common mode rejection

Answer 5

• the ability of an amplifier to reject like signals

- differential amplifier

Question 6

60 Hz filter has the greatest effect on

Answer 6

16 msec waveform

Question 7

voltage resolution

Answer 7

analog to digital converter

Question 8

time constant

Answer 8

LFF

Question 9

input impedance

Answer 9

high

Question 10

differential amplifier

Answer 10

magnifies common-mode voltage difference
differential amplification
info from 2 inputs and amplifying the difference

Question 11

Nyquist theorem

Answer 11

minimum sampling rate
2X the frequency of the highest waves
eX: HFF: 70 Hz min sample rate: 210
ACNS guideline: 3x the HFF

Question 12

frequency response curve

Answer 12

filters

Question 13

frequency response curve

Answer 13

sharpness is determined by the roll off

Question 14

double the inter-electrode distances

Answer 14

higher amplitude

Question 15

frequency

Answer 15

Hz

Question 16

frequency

Answer 16

sampling rate

Question 17

system gain

Answer 17

ratio of amplifiers to output to the input signal

Question 18

fast Fourier transform

Answer 18

converts time function into sine waves of different frequencies

Question 19

long time constant

Answer 19

LF .1 Hz

Question 20

time constant of .5 sec

Answer 20

LF .3 Hz

Question 21

ground electrode EEG

Answer 21

FPz

Question 22

delta wave best seen with filter

Answer 22

time constant 1.0 sec

Question 23

voltage resolution

Answer 23

analog to digital

Question 24

HFF of 15 Hz, what percent of amplitude is visible?

Answer 24

.7

Question 25

time constant for 3 Hz

Answer 25

.05 sec

Question 26

sampling rate for HFF of 70Hz

Answer 26

210 psec

Question 27

eliminate cortical spikes

Answer 27

change HFF from | 70 Hz to 15 Hz.

Question 28

3 Hz wave attenuated by what percentage of .3 Hz filter?

Answer 28

.3

Question 29

LFF is changed from 1 Hz to 5 Hz. | How is 2 Hz wave affected?

Answer 29

significantly attenuated

Question 30

LFF of 5 Hz will attenuate a 5 Hz wave

Answer 30

.3

Question 31

time constant for 3 Hz

Answer 31

.05 sec

Question 32

.5 Hz was is enhanced without affecting spike with this filter:

Answer 32

LFF .3 Hz

Question 33

signals with like frequency, amplitude and phase

Answer 33

are canceled

Question 34

vertical resolution

Answer 34

amplitude

Question 35

sampling rate

Answer 35

a signal sampled at intervals and assigned a numeric value

Question 36

When a 60 Hz sine is sampled at 100 Hz

Answer 36

aliasing

Question 37

long time constant

Answer 37

LFF .1 Hz

Question 38

A/D converter

Answer 38

converts analog signal into digital binary numbers

Question 39

high sampling rates

Answer 39

smooth connected lines

Question 40

ACNS guidelines for horizontal resolution

Answer 40

16 bits

Question 41

ability for amplifier to reject like signals

Answer 41

common mode rejection

Question 42

low sampling rate causes fast frequencies to appear slower | "undersampling"

Answer 42

aliasing

Question 43

input 1: +50 muV input 2: -100 muV what's the output voltage and deflection?

Answer 43

150 downward

Question 44

Not useful in digital EEG

Answer 44

biocal

Question 45

most sensitive

Answer 45

2 Uv/mm

Question 46

clipping of the waveforms happens

Answer 46

signal is outside of the range of the digitizer

Question 47

EEG amplifiers

Answer 47

differential | amplification

Question 48

increasing the # of seconds on monitor

Answer 48

No Change in Spike amplitude or duration

Question 49

digital EEG montages are reformatted usijng

Answer 49

system reference

Question 50

sensitivity

Answer 50

the amount increased by differential amplifier to magnify input signal

Question 51

a filter

Answer 51

alters the amplitude of frequencies