MEGR 3171  ·  UNC Charlotte Weekly Course Guides
Dr. Roger Tipton
Mechanical Engineering & Engineering Science
Week 4 of 15 MEGR 3171  ·  Module 1: Precision Measurement & Signal Science

Advanced Signal Conditioning

Design and analyze instrumentation amplifier circuits, Wheatstone bridge configurations, and lead-wire compensation schemes that condition real sensor signals to measurable levels.

Module 1  Precision Measurement & Signal Science Alciatore Ch. 4–5
Semester Progress
Week 4 / 15

Overview

Week 4 at a Glance

Week 4 moves into the hardware layer of the measurement chain. You will analyze instrumentation amplifiers (their CMRR advantage over op-amps), configure Wheatstone bridges in quarter-, half-, and full-bridge arrangements, and apply lead-wire and temperature compensation to achieve high-accuracy measurements in real environments.

This week directly supports the lab work in Weeks 7-10 where you will use these circuits to condition strain gauge, thermocouple, and force transducer signals.

Instrumentation amplifiersCMRRWheatstone bridgeBridge sensitivityLead-wire compensationBridge excitation
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Why it matters in practice. Strain gauges, load cells, RTDs, and most precision sensors produce millivolt-level signals buried in noise. An incorrectly configured bridge or low-CMRR amplifier will corrupt the measurement before it ever reaches the ADC.

Objectives

What You Will Be Able to Do

Course objectives (CO) define program-level skills. Module objectives (MO) define specific weekly targets that build toward them.

Course Objectives (CO)

CO3: Design signal conditioning circuits to meet target performance specifications.
CO4: Configure a data acquisition system correctly; apply Nyquist criterion.

Module Objectives (MO) — Week 4

Compute the output voltage of an instrumentation amplifier given input differential and common-mode voltages, gain, and CMRR.
CO3
Analyze quarter-, half-, and full-bridge Wheatstone configurations and compute bridge output voltage for a given gauge factor and strain.
CO3
Apply lead-wire and temperature compensation techniques to minimize systematic errors in bridge circuits.
CO3
Specify bridge excitation voltage and select an in-amp gain to achieve a target full-scale output voltage.
CO3
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Review these objectives before you start each assignment. They map directly to what is assessed on the quiz, homework, and exams.

Suggested Learning Path

How to Work Through This Week

Follow this sequence. Each step prepares you for the next. Do not attempt graded work before completing the instructional material it depends on.

1
Read Alciatore Ch. 4-5 (assigned sections)
Focus on the instrumentation amplifier analysis (Ch. 4) and Wheatstone bridge derivations (Ch. 5). Work through the quarter-bridge output equation from first principles before lecture.
2
Attend Lecture
Lecture 1 covers in-amps and CMRR. Lecture 2 covers bridge configurations and compensation. The problem session works a complete bridge-to-ADC signal chain specification.
3
Complete the Lab Signal Conditioning Exercise
Wire a quarter-bridge strain gauge circuit on your breadboard with a provided in-amp and verify the bridge output against calculated values. Record and report your results with uncertainty.
4
Submit Module 2 Homework — due this week
Module 2 Homework is due at the end of Week 4. Problems include CMRR calculation, bridge output for given strains, and full signal chain specification.

Instructional Material

Required Readings, Videos, and Resources

Complete all required items before moving to graded activities. The Aligns to column maps each resource to the module objectives it directly supports.

ResourceWhat You Will GainAligns toEst. Time
Read
Alciatore Ch. 4 (In-Amps) and Ch. 5 (Wheatstone Bridges) — assigned sections		 Instrumentation amplifier circuit analysis, CMRR derivation, bridge topology comparison, gauge factor application, and lead-wire error analysis. MO1-MO4 75-90 min
Lab
Lab: Quarter-Bridge Strain Gauge Circuit		 Build and characterize a quarter-bridge circuit. Measure CMRR experimentally and compare to datasheet specification. MO1, MO2 ~2 hr lab
Watch
Micro-lecture: Wheatstone Bridge Linearization		 3-minute clip on the nonlinearity error of the quarter-bridge and how half- and full-bridge configurations cancel it. MO2 3 min

Graded Learning Activities

Assignments and Due Dates

All graded work is submitted through Canvas. Complete the listed prerequisites before attempting each assignment.

AssignmentPrerequisitesWhat Is AssessedAligns toPoints
Module 2 Homework: Uncertainty Analysis
End of Week 4		 Complete Ch. 4-5 readings and attend both lectures. CMRR calculation, bridge output for multiple strain levels, signal chain specification, and uncertainty propagation through the bridge equation. MO1-MO4 50 pts
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Academic integrity. Bridge circuit measurements must be taken with your own hardware during the lab session. Copying numerical results from another student or a datasheet without performing the actual measurement is academic dishonesty.