LAB MANUAL FOR BIOMEDICAL INSTRURMENTATION LAB

 

Experiment No.1

Blood Pressure Measurement

Aim:

To Measure blood pressure using Sphygmomanometer.

Requirements:

1. Cuff
2. Inflator
3. Stethoscope
4. Sphygmomanometer

Theory:

Blood Pressure

            Blood pressure is a measurement of the force applied to the walls of the arteries as the heart pumps blood through the body. The pressure is determined by the force and amount of blood pumped, and the size and flexibility of the arteries. Blood pressure is continually changing depending on activity, temperature, diet, emotional state, posture, physical state, and medication use. The ventricles of heart have two states: systole (contraction) and diastole (relaxation). During diastole blood fills the ventricles and during systole the blood is pushed out of the heart into the arteries. The auricles contract anti- phase to the ventricles and chiefly serve to optimally fill the ventricles with blood. The corresponding pressure related to these states are referred to as systolic pressure and diastolic pressure .The range of systolic pressure can be from 90 mm of Hg to 145mm of Hg with the average being 120 mm of Hg. The diastolic pressure typically varies from 60mm of Hg to 90 mm of Hg and the average being 80 mm of Hg.

Procedure

1. Wrap the upper arm with the pressure cuff belt.
2. Increase the cuff pressure about 30 mmHg higher than the systolic blood pressure.
3. Decrease the cuff pressure slowly.
4. Note down the reading of manometer when the sound starts. This corresponds to systolic blood pressure.
5. Continue to decrease the pressure till the sound disappears. This corresponds to Diastolic blood pressure.

Spyhgmomanometer:

            This includes a mercury manometer, an upper arm cuff, a hand inflation bulb with a pressure control valve and requires the use of a stethoscope to listen to the Korotkoff sounds. Relies on the ausculatory technique.

 

S No.	Patient Name	Sphygmomanometer
		Systolic (mmHg)	Diastolic (mmHg)
1	X
2	Y
3	Z
4	A

 

Experiment No.2

Real time Acquisition of ECG Signal and measurement of ECG parameters

Aim:

To acquire real time ECG signal and measure its parameters.

Requirements:

1. Electrodes
2. Amplifier
3. Filter
4. DSO

Theory:

An electrocardiogram (ECG or sometimes EKG) is a reading of the electrical activity of the heart. The potentials originated in the individual fibers of heart muscle are added to produce the ECG wave form. The ECG reflects the rhythmic electrical depolarization and repolarization of the myocardium (heart muscle) associated with the contractions of the atria and ventricles.

It has 5 different wave deflections: P. Q, R, S and T. In general, ECGs are useful for detecting abnormal rhythms caused by damage to the autorhythmic fibers or abnormal levels of electrolytes such as potassium, sodium or calcium. They are often not as useful in detecting damage to cardiac muscle.

A typical ECG is taken using 12 lead system. The ECGs that are recorded in class, use 3 leads

The P, 0, R. S and T deflections and intervals between indicate the following:

            The P wave represents the electrical signal produced by the SA node in the right atrium and the propagation of that impulse to the AV node and to the cardiac muscles of the atria.

 

            The PR/PQ interval runs from the beginning of the P wave to the beginnipg of the QRS complex. During this interval includes what is mentioned in the P wave as well as the contraction produced by the atrial cardiac muscles. Atnal contraction occurs during the flat part of the interval.

 

            The QRS complex represents the depolarization of the ventricles. Reflected in this is the movement of the electrical signal down the AV bundle, right and left bundle branches, Purkinje fibers and the propagation of that signal to the cardiac muscles of the ventricles. Because of the greater muscle mass of the ventricles, the signal is much larger than the P wave. Also during this time you have repolarization of the atrial cardiac muscles, however the electrical signal is masked by the large depolarization produced by the ventricular muscles.

 

            The ST interval represents the contraction of the ventricles. It is measured from the junction of where QRS ends and the T wave begins.

 

            The T wave represents the repolarization of the ventricles. The absolute refractory period occurs during the ST Interval and extends to the apex of the T wave. The relative refractory period the latter half of the T wave.

            The QT interval runs from the beginning of the QRS complex to the end of the T wave. This represents the time it takes for depolarization and repolarization of the ventricles. This interval will vary with heart rate.

 

Procedure

1. Connect the 3 leads one on each, right arm, left arm, left leg and the ground lead will be connected on the right leg.
2. Connect the outputs of the leads to DSO through amplifier and filter.
3. Measure the various ECG parameters which are listed in table below.

 

Tabulation:

 

Subject	P wave		QRS Complex				T wave
	Amplitude in mv	Duration in mm	Q amplitude in mv	R amplitude in mv	S amplitude in mv	QRS duration in ms	Amplitude in mv	Duration in mm
1
2
3

 

Experiment No. 3

Measurement of peripheral pulse rate using Plethysmograph

 

Aim:

To measure the peripheral pulse rate. (finger plethysmography)

Requirements:

1. Finger Plethysmograph
2. Pulse Sensor I
3. DSO

Theory:

            Pulse is usually called as heart rate, which is number of times heart beats each minute (bpm).It gives information about how well the heart is working. It checks general health and overall fitness level. There are various techniques to measure pulse or heart rate. Heart rate is very important parameter in medical field. Average heart rate of human being is adult male is 70 bpm and 75 bpm for adult female, babies heart rate ranges around 120 bpm and older children it is around 90 bpm. Heart rate increases during exercise and varies with fitness and age. If heart rate is lower than the threshold level then bradycardia occurs and if higher, then tachycardia.

A finger Plethysmograph is used to measure peripheral pulse.

 

Pulse rate:

            Pulse rate is the number of pulsation per minute palpable in an artery, usually of a limb

 

Peripheral pulse sensor:

            A peripheral pulse sensor is a particular convenient non-invasive method of measuring peripheral pulse. Typically It has a pair of small light emitting diode (LED) and light dependent resistor (LDR) placed over a translucent part of the subject’s body usually a fingertip or an earlobe.

 

Procedure:

1. Switch ON the system.
2. Place the sensor on the finger and connect it to the system.
3. Take pulse count for one minute.
4. Measure the duration between two pulses and calculate the pulse rate.

 

Tabulation:

Subject	Display reading Bprn	Pulse rate in bpm=60000/R-R interval
1
2
3
4
5

 Theory of LabVIEW (Laboratory Virtual Instrument Engineering Workbench)

What Is LabVIEW?

            LabVIEW is a program development application, much like various commercial C or BASIC development systems, or National Instruments Lab Windows. However, LabVIEW is different from those applications in one important respect. Other programming systems use text-based languages to create lines of code, while LabVIEW uses a graphical programming language to create programs In block diagram form.

 How Does LabVIEW Work?

            LabVIEW includes libraries of functions and development tools designed specifically for instrument control. LabVIEW also contains libraries of functions and development tools for data acquisition. LabVIEW programs are called virtual instruments (VIs) because their appearance and operation Imitate actual instruments. However, they are analogous to functions from conventional language programs. VIs has both an interactive user interface and a source code equivalent and accept parameters from higher-level VIs.

 Virtual Instruments

LabVIEW programs are called virtual instruments (VIs), VIs have three main parts: the

front panel, the block diagram, and the icon/connector.

• Front Panel - Serves as the user interface.
• Block diagram - Contains the graphical source code that defines the functionality of the VI.
• Icon and connector Dane - Identifies the VI so that you can use the VI In another VI.

            A VI within another VI is called a sub VI. A sub VI

            Corresponds to a subroutine in text-based programming

            Languages

 Terminals: The terminals represent the data type of the control or indicator. You can configure front panel controls or indicators to appear as icon or data type terminals on the block diagram.

 

Nodes: Nodes are objects on the block diagram that have inputs and/or outputs and perform operations when a VI runs.

 

Wires: Transfer of data among block diagram objects is done through wires.

 

Structures: Structures are graphical representations of the loops and case statements of text-based programming languages.

Experiment No. 4

Addition, Subtraction, Multiplication and Division of Numbers

 AIM: Perform addition, subtraction, multiplication and division of two numbers

 Requirements:

LabVIEW software

Procedure:

Step 1: Start the Lab view and select the blank VI.

Step 2: Create front and block diagram panel.

Step 3: Right click on the front panel and select numeric controls as inputs and numeric indicators as output

Step 4: Generate different arithmetic operators such as addition, subtraction, multiplication and division in block diagram panel.

Step 5: Using wiring operation connect inputs and outputs to the respective operators in the block diagram panel.

Step 6: Give the input values in the front panel, run the program and note down the output.

Experiment No 5

Realization of AND gate, OR gate, NOT gate, NAND gate, NOR gate, XOR gate using LabVIEW

 

AIM: Realization of AND gate, OR gate, NOT gate, NAND gate, NOR gate and XOR gate using LabVIEW

Requirements:

LABVIEW software.

Procedure:

Step 1: Start the LabVIEW and select the blank VI.

Step 2: Create front panel and block diagram panel.

Step 3: Select push buttons as inputs and round LED as output.

Step 4: Select the different Boolean operations such as AND, OR, XOR, NOT, NAND from the block diagram panel.

Step 5: Wire the boolean inputs and outputs in the block diagram panel.

Step 6: Give the inputs and verify the truth tables.

Experiment No.6

Measurement of Heart Rate using RR Interval

Aim:

To acquire the heart rate using R-R interval time using ECG

Requirements:

5. Electrodes
6. Amplifier
7. Filter
8. DSO

Theory:

            RR interval, in the time lapsed between two successive R waves of the QRS signal on the electro cardiogram (ECG) is a function of intrinsic properties of the sinus node as well as cuttonanic influences, artial and ventricular depolarization and repolarization are represented on the ECG as a series of waves the Pwave followed by the QRS complex and Twave. The first deflection in the ‘P’ wave associated with right and left atrial depolarization wave of atrial repolarization is invisible because of low amplitude.

            \Normal Heart Rate = 72bpm

Tabular Column:

S No	Subject	RR interval in ms	Calculated heart rate in bpm
1
2
3
4

 

Calculation:

1.             bpm à = 82 bpm

     

 Experiment No.7

PHONOCARDIOGRAM (PCG)

Aim:

To measure or record the sound of heat beat with pumping action of heart

Components:

1. DSO
2. PCG Sensor
3. Multiparameter Devices

 

Theory:

            A phonocardiogram (or PCG) is a plot of high fidelity recording of the sounds and murmur made by the heart with the help of the machine called the phonocardiograph. Thus phonocardiography is the recording of all the sounds made by the heart during a cardiac cycle. From this, we can hear the two sounds when heat beats which are Lub and Dub. The sounds result from vibrations created by closure of the heart values, these are at least two; the first when the antiventricular value close at the beginning of systole and the second when the aortic value and pulmonary value close at the end of systole.

• Two types of phonocardiogram used for recording
• Microphone type and
• Crystal type phonocardiogram

Procedure:

1. Connections are made as per the circuit diagram
2. Switch on the components
3. The microphone type phonocardiogram is connected to subject heart or crystal type phonocardiogram is connected to subject heart by applying gel on base of the PCG
4. Measure the amplitude and duration of the ‘Lub’ and ‘Dub’ sound
5. Note down the readings and repeat the same for further readings.

Experiment No.8

ELECTROMYOGRAPHY (EMG)

Aim:

To evaluate the health condition of muscles and the nerve cells that control them.

Equipments Required:

1. Dual Power Supply
2. DSO Wires
3. Multiparameter Devices
4. Electrodes

 

Theory:

            Electromyography (EMG) is a diagnostic procedure that evaluate the health conditions of muscles and the nerve cells that control them. These nerve cells are known as motor nervous. They transmit electrical signals that causes muscles to contract and relax the test is used to help detect neuro muscular abnormalities. During the test, one or more small needles (also called as electrodes) are inserted into the muscles through the skin.

Procedure:

1. make the connections as per block diagram.
2. Short the wires of positive and negative voltage of dual power supply.
3. Apply the gel to lift hand and start increasing the voltage till the waveform is appeared clearly.
4. Note down the readings.
5. repeat the same steps for further readings.

1. Same as EMG only put the gain knob at minimum position.
2. Before electrodes connecting to body put all knob position at zero position.
3. Electrode position put as figure
4. EMG mode switch on EMG gain at zero position stimulator pulse mode switch at 0.7ms now increase the intensity slowly. See the response on DSO.

Experiment No.9

INSTRUMENTATION AMPLIFIER

Aim:

To design and study instrumentation amplifier for the given gain.

Components:

1. Resistors
2. Power Supply
3. Breadboard
4. Op-amp connecting wires

 

Procedures:

1. Make the connections as per the circuit diagram.
2. Rig up the circuit as shown in figure.
3. Give the input V₂ = 1.5v and V₁ = 1.0v at Pin No.3 of IC (1) & IC (2)
4. Note down the output voltage V₀ at Pin No.6 of IC (3)
5. Compare the practical values with theoretical values.
6. Repeat the procedure for different input.

 Tabular Column:

Activity on Subjects	Normal Activity O/p voltage	Soft Activity o/p voltage	Load in hand activity o/p voltage	Stimulator Activity o/p voltage

 

Design:

R₁ = R₃ = R₄ = 100kW

Assuming gain of 10 find out the value of R₂ using

                       

Where A is gain

 Tabular Column:

Sl No	Gain (A)	R2 in W	Practical Values	Theoretical Values
01

 

Calculation:

R₁ = R₃ = R₄ = 100kW

1. A = 10	2. A = 2
3. A = 5	4. A = 3

 

5. A = 50

           

 

1.         V0 = -A (V
2.         For A = 2             V0 = - A (V1
3.         For A = 5             V0 = - A (V1
4.         For A = 3             V0 = -
5.         For A = 50             V0 = - A (V1

 

Experiment No.10

NOTCH FILTER

Aim:

To design a notch filter for a cut off frequency of 50Hz and to plot the frequency response.

Components:

1. Function generator
2. Regulated power supply
3. Resistors (33k, 100k, 1k)
4. Capacitors 01mF(4)

 

Procedures:

1. The circuit is set up as shown in circuit diagram and all equipments are switched on.
2. In the function generator, the amplitude of sinewave is kept constant as 10v
3. The input frequency is varied in steps
4. The amplitude of wave for each o/p is noted down
5. Gain Vo/Vi and gain in dB = 20 log (Vo/Vi) are calculated for each frequency, tabulated  and is plotted on semilog graph sheet.

 

Circuit Diagram:

Nature of Graph:

 

 

 

 

 

 

 

Design:

           

 

Tabular Column:

S No.	Frequency in Hz	Output Vo	Gain = Vo/Vi	Gain in dB=20 log (Vo/Vi)
1
2
3
4
5

 

Experiment No.11

SECOND ORDER BUTTER-WORTH HIGH PASS FILTER

Aim:

To design a second order butter worth high pass filter for a cut off frequency of 0.05Hz to plot the frequency response.

Components Required:

1. Resistors 3.2MW
2. Capacitors (1mF) (2)
3. Op-amp LM741 (1)
4. Function Generator RPS and CRO

 

Procedures:

            The circuit is connected as shown in the circuit diagram all the equipment are switched ‘ON’ the function generator is kept in sinewave mode and the amplitude of sinewave is adjusted to a constant value of 5v. The frequency is varied in suitable steps from 0 to 10000 Hz for each frequency the amplitude of O/p voltage is noted, for each frequency, the gain (Vo/Vi) and dB gain = 20 log₁₀ (Vo/Vi) are calculated and tabulated.

 

Tabular Column:

S No.	Frequency in Hz	Output Vo in (v)	Gain = Vo/Vi	Gain in dB=20 log (Vo/Vi)
1
2
3
4
5
6
7
8
9
10

Experiment No.12

LOW PASS FILTER

Aim:

To design a second order butter worth low pass filter for a cut off frequency of 100Hz and to plot the frequency response.

 

Components Required:

1. Function generator
2. Regulated power supply
3. Resistors (15kW, 100kW, 1kW)
4. Capacitor 0.1mF

 

Procedures:

1. The circuit is connected as shown in circuit diagram and all equipments are switched On
2. The function generator is kept in ‘Sine Wave’ mode and the amplitude of 1/P sine wave is kept constant at 10v
3. The frequency i/P is varied in suitable steps the amplitude of o/p is noted down for each frequency
4. The gain C1 = Vo/Vi and gain in dB = 20log₁₀ (Vo/Vi) is calculated for each frequency and then tabulated.

 

Tabular Column:

S No.	Frequency in Hz	Output Vo in (v)	Gain = Vo/Vi	Gain in dB=20 log (Vo/Vi)
1
2
3
4
5
6
7
8
9
10