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Signature of the invigilator: Roll no.:

C B . E N . U 4

Amrita Vishwa Vidyapeetham

B.Tech. Degree Examinations – Nov/Dec. 2014

Seventh Semester

Electronics and Communication Engineering

ECE453 Biomedical Signal Processing Time: Three hours Maximum: 100 Marks

Answer all questions

1) Fill in the blanks: (15 x 2 = 30 Marks)

a) The neurotransmitter which initiates sleep is------------------------------------------------------

b) The electrical activity of muscles is recorded as -------------------------------------------.

c) The arrhythmic condition in which the heart rate is decreased from normal is named as--

------------------------------------.

d) The U wave in ECG signal represents the depolarization of ----------------------------------

e) The alteration in an ongoing EEG signal due to sudden flash of light is-----------------------

------------------------------------.

f) A theta wave in EEG signal will be in ----------------frequency range and it indicates that

the person is in--------------------metal condition.

g) The Fourier transform of rect is----------------------------------------------.

h) Process of changing from a resting state to the generation of an action potential is called

-------------------------------------and the process of changing from action potential back to

the resting state is called--------------------------

i) In resting state the cell membrane is less permeable for-----------ions and highly

permeable for------------ions

j) The time during which the cell is depolarized and can be restimulated to another action

event is called--------------------

Date:

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k) During resting state, inside of the cell has a slightly -----------------------------potential

when compared to outside.

l) Impulse signal δ(t) can be represented in terms of unit step signal u(t) as --------------------

m) The time during which the cell is depolarized and cannot be restimulated to another

action event is called--------------------

n) The anatomically specialized junction between two neurons is called---------------------and

it is characterized by the presence of---------------------which enhances conduction

between the neurons.

o) The axon of a nerve cell is insulated with ----------------------------------.

2) Match the following (10 x 2 = 20 Marks)

(a) Delta waves (i)seizures

(b)ERP (ii)Arrhythmia

(c)4-7Hz (iii)5-30 minutes

(d)Small window size (STFT) (iv)Auditory stimulus

(e)epilepsy (v)Weiner filtering

(f)Tachycardia (vi)neurotransmitter

(g)REM (vii)0-4Hz

(h)power line interference (viii)Good time resolution

(i)LMS algorithm (ix)Beta waves

(j)Acetyl choline (x)Above 12.5

(xi) 60Hz

(xii)Theta waves

(xiii) Good frequency resolution

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Ans:

(a) (b) (c) (d) (e) (f) (g) (h) (i) (j)

3) (a) Name the parts labeled: (5 x 1 = 5 marks)

Ans:

(A) (B) (E)

(C) (D)

(b) Consider a continuous time signal x(t) defined as x(t) = sketch

the input signal and output signals y1(t) and y2(t) for the continuous system

(5 Marks)

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Ans:

i/p / o/p Plot

x(t)

y1(t)

y2(t)

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4) The EEG signal obtained from a person has amplitudes x(n)=(0. 3 ,0.5 ,0.1) at

discrete intervals of time. And if the amplitude is greater than 0.7mV it indicates an

epileptic seizure. By using parametric modeling predict whether this person will

have epilepsy or not. You can use the next two amplitude values. (10Marks)

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5) Fill the table and mark all the parameters in the given ECG signal (15 marks)

Feature Explanation ,Duration & Amplitude)

PR interval

PR segment

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QRS complex

ST segment

QT interval

6) For recording ECG signals two lead systems are used limb lead system and chest lead

system. In each of these systems there will be one positive electrode, negative

electrode and one reference. Fill the table below for each of the lead system.

(10Marks)

Lead Name +ve electrode

- ve electrode

Standard limb lead system

Lead I

Lead II

Lead III

Augmented limb lead system

aVR

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aVL

aVF

Chest lead system

V1

V2

V3

V4

V5

V6

7) A man who sleeps for 8 hrs has the following probabilities of sleep stage transitions. Draw

the markov chain generated by the matrix and find the probability such that first state was

W then it changes to R then to S3 (5Marks)

(Hint:- W-Wakefulness,R-REM,S1S2S3-Stage 1,2 3)

W R S1 S2 S3

W 0 .02 .033 .01 .001

R 0.3 0 0 0.43 0.56

S1 0.5 0.70 0.67 0.27 0.13

S2 0.45 0.258 0.87 0.57 0.02

S3 0.22 0.67 0.234 0.567 0.765

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Space for rough work