Clinical Finger-Clip Pulse Oximeter Probe
Provides dual-wavelength red (660 nm) and infrared (940 nm) LEDs and silicon PIN photodiode.
Biomedical Engineering / Pulse Oximeter PPG Calibration
FREE TO EXPLORELABORATORY 10 · BIOMEDICAL ENGINEERING
Pulse Oximeter Dual-Wavelength PPG & Ratio-of-Ratios Calibration
Determine the ratio-of-ratios parameter R = (AC660/DC660) / (AC940/DC940) across blood oxygen saturations (SpO2) and calibrate the empirical calibration curve. Explore interactive physiological instrumentation simulation, biomechanics, and biomedical engineering telemetry.
BIOINSTRUMENTATION · BIOSIGNALS · BIOMECHANICS · IMAGING
Your virtual biomedical engineering laboratory.
ARTERIAL OXYGEN SATURATION SPO2—
PHYSIOLOGICAL & TEST CELL TELEMETRY
Ready to sample with Ratio R = 0.8 ratio.
Adjust Ratio R, 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 calibration model applies across the clinical diagnostic range (SpO2 75% to 100%). Evaluated using a clinical finger-clip probe with 660 nm red LED and 940 nm infrared LED paired with a low-noise silicon PIN photodiode. Calibrated across ratio-of-ratios R from 0.40 (SpO2 = 100%) to 1.40 (SpO2 = 75%) in 0.20 increments.
Biomedical apparatus & physiological sensors.
Optical Tissue-Blood Perfusion Phantom
Calibrated optical phantom with variable pulsatile blood mimicking fluid and controlled oxygenation.
Dual-Wavelength LED Multiplex Driver
Switches red and infrared LEDs alternately at 500 Hz with dark interval for ambient cancellation.
Precision Co-Oximeter Blood Reference Analyzer
Measures true fractional oxygen saturation (SaO2) via multi-wavelength spectrophotometry.
Photodiode Transimpedance Preamplifier & Demodulator
Separates 660 nm and 940 nm channels and splits each into filtered AC and DC analog signals.
Digital Signal Processor Telemetry Console
Samples PPG signals, extracts pulse peak-to-peak amplitudes, and calculates modulation ratio R.
FOLLOW THE METHOD
A reason behind every step.
Determine the ratio-of-ratios parameter R = (AC660/DC660) / (AC940/DC940) across blood oxygen saturations (SpO2) and calibrate the empirical calibration curve. Standardized parameter settings: 0.4, 0.6, 0.8, 1.0, 1.2, 1.4 ratio.
01
Optical Alignment and Ambient Light Cancellation
Clip the sensor probe onto the optical phantom; verify that the ambient dark-period subtraction circuit eliminates background room light hum.
02
LED Drive Current Standardization
Adjust LED drive currents so that baseline DC voltages on both red and infrared channels settle to equal 2.000 V levels.
03
Full Oxygenation Baseline (R = 0.40)
Oxygenate blood phantom to 100.0% SaO2; record pulsatile AC and DC amplitudes, confirming ratio R = (AC660/DC660)/(AC940/DC940) = 0.400.
04
Controlled Desaturation Step Progression
Deoxygenate the circulating phantom fluid in controlled steps to achieve parameter R values of 0.60, 0.80, 1.00, 1.20, and 1.40.
05
Simultaneous Reference SpO2 Logging
Record gold-standard SaO2 from the bench co-oximeter and log corresponding SpO2 readings over 20 cardiac pulse cycles.
06
Calibration Curve Regression Analysis
Plot SpO2 against modulation ratio R, fitting least-squares linear regression to determine calibration slope k_ox and intercept SpO2,0.
YOUR NOTEBOOK · 0 OBSERVATIONS
Turn measurements into biomedical engineering insight.
Points are your recorded observations. The solid regression line validates Pulse Oximeter PPG Calibration mathematical scaling.
LINEAR REGRESSION FIT · y = mx + b
SpO2 = -k_ox · R + SpO2,0 = -25.0000 · R + 110.0000
| # | Ratio-of-Ratios Parameter R (ratio) | Arterial Oxygen Saturation SpO2 (%) | Ratio-of-ratios parameter R (ratio) | Oxygen saturation SpO2 (%) | Remove |
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