PE2-3.1 Introduction to Biomedical Signals
You can explain action potential generation and describe the origin and waveform characteristics of ECG, EEG, EMG, PCG, ENG, ERP and EGG, and state the objectives and difficulties of biomedical signal analysis.
Every signal in this course starts as an action potential in a cell, so understanding that one mechanism explains why all of them look the way they do. Learn each signal by its amplitude and frequency band — an ECG is millivolts, an EEG microvolts — because those numbers dictate the entire amplifier design in Unit 3. The difficulties section deserves real attention: biomedical signals are non-stationary, patient-specific and buried in interference, which is why methods that work on radio signals often disappoint here.
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Action potential and its generation
Where every signal in this subject comes from: a cell changing its membrane voltage. Nothing later makes sense without this, so it is worth the time.
Electrocardiogram (ECG): origin and waveform characteristics
The heart's signal, and the letters used to name its parts. It is the most measured signal in medicine and the reference for the whole course.
Electroencephalogram (EEG) and Electromyogram (EMG)
The brain's and the muscle's signals, which are far smaller and noisier. The amplitude difference is why the amplifier topic later is so demanding.
Phonocardiogram (PCG) and Electroneurogram (ENG)
Two more signals, one acoustic and one from a nerve. They broaden the picture beyond the electrical signals above.
Event-related potentials (ERPs) and Electrogastrogram (EGG)
Signals produced in response to a stimulus, and one from the gut. Event-related potentials are buried in noise and recovered by averaging, which the filtering topic explains.
Objectives of biomedical signal analysis
What you are actually trying to achieve by analysing any of these. Stating the objective first is what keeps the technique choice honest.
Difficulties in biomedical signal analysis
Why this is harder than ordinary signal processing: the signal is small, the interference is large, and it is often another physiological signal. It is the honest framing of the subject.
Computer-aided diagnosis
Where all of this is heading, which is a system that supports a clinician rather than replaces one. That framing matters for how the results are presented.
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