Three-Op-Amp Precision Instrumentation Amplifier
Provides buffered high-input-impedance (10 GΩ) differential biopotential amplification.
Biomedical Engineering / Instrumentation Amplifier CMRR
FREE TO EXPLORELABORATORY 05 · BIOMEDICAL ENGINEERING
Three-Op-Amp Instrumentation Amplifier Common-Mode Rejection Ratio (CMRR)
Measure differential gain and common-mode gain of a classic three-op-amp biomedical instrumentation amplifier to calculate CMRR across common-mode interference voltages. Explore interactive physiological instrumentation simulation, biomechanics, and biomedical engineering telemetry.
BIOINSTRUMENTATION · BIOSIGNALS · BIOMECHANICS · IMAGING
Your virtual biomedical engineering laboratory.
COMMON-MODE OUTPUT VOLTAGE V_OUT,CM—
PHYSIOLOGICAL & TEST CELL TELEMETRY
Ready to sample with V_cm = 1.5 V.
Adjust V_cm, then execute biomedical trial.
Biomedical engineering telemetry and physiological states are evaluated rigorously using 64-bit IEEE 754 precision. Residuals reflect ordinary least-squares regression across successive observations. Continuous data structures support high-fidelity biological and physiological modeling.
Biomedical assumptions and boundary condition limits
The linear leakage model applies within the linear common-mode input range (V_cm ≤ 3.0 V). Evaluated using a low-noise medical instrumentation amplifier (INA118 precision architecture) configured for fixed differential gain A_d = 1000. Common-mode gain A_cm is evaluated across 60 Hz sinusoidal common-mode voltages from 0.5 V to 3.0 V RMS.
Biomedical apparatus & physiological sensors.
Calibrated Precision Resistor Network (0.01% matched)
Establishes difference stage symmetry to achieve high common-mode rejection.
Dual-Channel Arbitrary Function Generator
Supplies calibrated 60 Hz common-mode sinusoidal test voltages from 0.5 V to 3.0 V RMS.
Low-Noise True-RMS Digital Microvoltmeter
Measures microvolt-level common-mode leakage output V_out,cm with 100 nV resolution.
Dual Regulated DC Power Supply (±15.00 V)
Powers the operational amplifier rails with ultra-low thermal noise and ripple.
Digital Storage Oscilloscope with FFT Spectrum Analyzer
Monitors output waveform purity and verifies absence of rail saturation or clipping.
FOLLOW THE METHOD
A reason behind every step.
Measure differential gain and common-mode gain of a classic three-op-amp biomedical instrumentation amplifier to calculate CMRR across common-mode interference voltages. Standardized parameter settings: 0.5, 1.0, 1.5, 2.0, 2.5, 3.0 V.
01
Differential Gain Verification
Apply a 1.000 mV peak-to-peak 10 Hz pure differential input signal; verify that differential output reads exactly 1.000 V peak-to-peak, confirming A_d = 1000 V/V.
02
Common-Mode Test Configuration
Tie both differential non-inverting and inverting inputs together to apply identical common-mode voltage V_cm simultaneously.
03
Initial Common-Mode Excitation
Apply a 60 Hz sinusoidal common-mode voltage of 0.500 V RMS, monitoring amplifier rails to ensure linear range.
04
Microvolt Output Leakage Measurement
Measure the residual 60 Hz output voltage V_out,cm using the precision true-RMS microvoltmeter over a 30-second integration window.
05
Common-Mode Progression Sequence
Increment common-mode voltage V_cm through 1.0, 1.5, 2.0, 2.5, and 3.0 V RMS, recording V_out,cm at each stage.
06
Gain Regression and CMRR Computation
Plot V_out,cm against V_cm to determine common-mode gain A_cm = slope / 1000 (in V/V), then calculate CMRR = 20·log10(A_d / A_cm).
YOUR NOTEBOOK · 0 OBSERVATIONS
Turn measurements into biomedical engineering insight.
Points are your recorded observations. The solid regression line validates Instrumentation Amplifier CMRR mathematical scaling.
LINEAR REGRESSION FIT · y = mx + b
V_out,cm = A_cm · V_cm = 0.0480 · V_cm
| # | Common-Mode Input Voltage V_cm (V) | Common-Mode Output Voltage V_out,cm (mV) | Common-mode input V_cm (V) | Common-mode output V_out,cm (mV) | Remove |
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