BIOM 5100/SYSC 5302 - Final Exam - December 10, 2008

Sep 27, 2026

Uploaded by Levi

Final examination paper for BIOM 5100/SYSC 5302 at Carleton University (Systems and Computer Engineering), dated December 10, 2008. The exam is closed book with an allowed single sheet of notes and a 180-minute limit, requiring answers to any two of three questions. Topics cover ECG acquisition during exercise, including motion, sweat, and EMG artifacts, waveform interpretation, amplifier gain/common-mode rejection, and electrode voltage changes due to sweat. Additional sections address breathing measurement using a Fleisch-type pneumotach, gas-flow resistance, practical issues, and lung volume maneuvers.

LanguageEnglish

CategoryExam

FormatPDF

Pages3

Reading Time8 min

AccessFree to download

1. ECG Measurement

ECG exercise measurement issues and electrode models

ECG waveform and heart rate estimation

Differential vs common-mode output in an amplifier

Electrode gel chloride concentration and electrode voltage change

2. Breathing Measurement

Pneumotach working principle and flow measurement

Fleisch-type pneumotach resistance estimation

Pneumotach problems and mitigation approaches

Vital capacity maneuver and lung volume calculations

Heliox experiment and residual capacity

Pulse oximeter working principle

Carleton University, Systems and Computer Engineering BIOM 5100/SYSC 5302: Final Exam: December 10, 2008 Instructor: Andy Adler Instructions: -This exam has 3 pages and 3 questions. Answer any two (2) of them. Marks are indicated -You have 180 minutes to complete this exam. -This is a closed book exam; however, you are permitted to bring one 8:5" 􀀂 11" sheet of notes. -Write your answers on an examination booklet. You may take this examination paper with you -You may use the following equations and constants: E = mc2 Rc = (8􀀑L)= (􀀙r4 ) E = E0 + RTnF ln ac c = 3 􀀂 108 ~~m~~s F = m_ a P = VR 􀀚 air = 1:21~~k~~m~~g3~~ Lc = (􀀚L)= (􀀙r2 ) C = (􀀁 V )=(􀀁P ) P ( VN )􀀋 =Const 􀀚 blood = 1060 ~~k~~m~~g3~~ R = 8:31 J/(K􀀁mol) F = 9:65 􀀂 104 C~~ou~~mol~~l~~dV + V􀀋PdP = ~~1~~􀀚dN 􀀑 air = 1:8 􀀂 10􀀀6 Pa􀀁s Charge e 􀀀 : 1:6 􀀂 10􀀀19 Coul Patm = 101:3 kPa = 760 mmHg 1 mol = 6:02 􀀂 1023 particles Resistivity: 􀀚 blood = 450􀀊􀀁cm 􀀑 blood 􀀙 3:0 􀀂 10􀀀3 Pa􀀁s 1. ECG Measurement We would like to monitor the heart rate of a subject while she is exercising. Exercise causes three main difﬁculties for measurement of the ECG: a) movement artefacts, b) sweat on the electrodes, and c) artefacts from the EMG in the ECG. We consider two different electrodes systems to measure the ECG. \#1) we place two Ag/AgCl electrodes each shoulder of the subject, and \#2) we ask the subject to hold onto stainless steel handles which act as electrodes. (a) (5 points) Brieﬂy describe the origin of movement artefacts. Use an equation or diagram if necessary. Do movement artefacts differ for electrodes \#1 and \#2? Explain (􀀔 50 words) . (b) (5 points) Brieﬂy describe the effect of sweat on the electrodes. Show equivalent electrical models of the electrodes. Does sweat affect electrodes \#1 and \#2 differently? Explain (􀀔 50 words) . (c) (5 points) Brieﬂy describe how artefacts from the EMG affect the ECG. Can a ﬁlter be used to clean the signal? Use a diagram if necessary. How is the effect different on electrodes \#1 and \#2 different? Explain (􀀔 50 words) . (d) (5 points) Draw a diagram of the ECG waveform. Label the P,Q,R,S, and T events. In a segment of the ECG, R waves occur at the following times (after the start of measurement) 9:95s, 10:49s, 11:23s, 11:61s, and 12:45s. Estimate the heart rate (in beats/min). (e) (10 points) Consider the circuit diagram shown. The ampliﬁer is conﬁgured so that the differential gain is 100. From the speciﬁcations of the ampliﬁer, it has a common mode rejection ratio of 80 dB and an input impedance, Zin, of 1 M􀀊 . Two stainless steel electrodes are attached with electrode model parameters Cd = 0:3 􀀖F and Rs = 1 k􀀊 . The common mode voltage due to power-line interference is 3:0 V and the differential voltage is 3:0 mV (which can can consider to be at 10 Hz) . What is the ratio of the differential to common mode signal at the ampliﬁer output, V0 ? (f) (10 points) Consider a standard Ag/AgCl electrode where the electrode gel is modiﬁed by sweat from the subject. When fresh out of the package, the electrode gel has a concentration [Cl 􀀀 ]= 0:1~~m~~L~~ol~~ . Sweat has approximately [Cl 􀀀 ]􀀙 0:01~~m~~L~~ol~~ , and thus will reduce the concentration in the gel. Calculate the change in electrode voltage when [Cl 􀀀 ] changes from 0:1~~m~~L~~ol~~ to 0:05~~m~~L~~ol~~. Assume skin temperature is 30oC. In practice, will sweat show up as a fast or slow contribution to the signal, and as a differential or common mode effect? 2. Breathing Measurement We wish to measure breathing parameters patient from a patient using a Fleisch-type pneumotach as shown at right and a fast gas analyzer.([Image reproduced from](Image reproduced from spirxpert.com/technical2.htm)[ spirxpert.com/technical2.htm](Image reproduced from spirxpert.com/technical2.htm)) (a) (5 points) How does such a pneumotach work? Sketch a diagram showing how it is connected to a patient, and what measurements are made on it. Brieﬂy (􀀔 30 words) des

FAQs

What is required to complete the ECG measurement section of the exam?

Answer subquestions covering origins of motion artifacts, sweat effects using electrical models, EMG artifact impact and filtering, ECG waveform labeling with heart rate estimation, amplifier differential versus common-mode output, and electrode voltage change from sweat-induced chloride concentration changes.

How are the ECG measurement electrodes set up in the exam?

Two Ag/AgCl electrodes are placed on each shoulder (electrodes #1), or the subject holds stainless steel handles that act as electrodes (electrodes #2). The questions compare how artifacts differ between these systems.

How does the Fleisch-type pneumotach measure airflow and what must be discussed in its problem section?

It measures airflow by relating pressure/flow through many small channels to determine air flow rate. The exam also asks to explain one issue such as signal level changes due to heating/humidification or condensation blocking, and to propose a way to address it.

Sep 27, 2026

Uploaded by Levi