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Chapter 31

Biomedical signals

Two lessons in Part XI, Applications. Read them in order, or start anywhere: a prerequisite is a link, never a gate.

Start with 31.1
0 of 2 readabout 34 minutes

Lessons in this chapter

One panel, millivolts from −1 to 2 against time in seconds from 3 to 6. The clean ECG is dashed and labelled clean, with R spikes at 3.62, 4.40, 5.17 and 5.95 s. The solid line, labelled low-pass, is the trace after the high-pass, the notch and the low-pass, from −0.31 to 0.93 mV. Its error RMS against the clean ECG over seconds 1 to 9 is 82 µV.One panel, millivolts from −1 to 2 against time in seconds from 3 to 6. The clean ECG is dashed and labelled clean, with R spikes at 3.62, 4.40, 5.17 and 5.95 s. The solid line, labelled low-pass, is the trace after the high-pass, the notch and the low-pass, from −0.31 to 0.93 mV. Its error RMS against the clean ECG over seconds 1 to 9 is 82 µV.

Lesson 118 minYou are hereRead

ECG processing

Clean a synthetic ECG with a high-pass, a notch and a low-pass, then find its beats with Pan–Tompkins and read the heart rate.

Two stacked panels over 0 to 30 s. EEG panel: the synthetic record in µV, from −46.3 to 111.5, against dotted reject levels at plus and minus 75 µV; four blinks rise above the upper one; the eyes-closed span, 10 to 20 s, is shaded. Relative band power panel: 29 windows of 29 drawn, centred at 1 to 29 s; alpha's share as dots on a solid line, delta's as squares on a dashed line; 10 rejected windows (centred at 2, 3, 4, 6, 7, 8, 21, 22, 23 and 24 s) shown as open crosses at their delta share. Span 20 to 30 s: alpha 22 %, delta 28 %, mean over the kept windows.Two stacked panels over 0 to 30 s. EEG panel: the synthetic record in µV, from −46.3 to 111.5, against dotted reject levels at plus and minus 75 µV; four blinks rise above the upper one; the eyes-closed span, 10 to 20 s, is shaded. Relative band power panel: 29 windows of 29 drawn, centred at 1 to 29 s; alpha's share as dots on a solid line, delta's as squares on a dashed line; 10 rejected windows (centred at 2, 3, 4, 6, 7, 8, 21, 22, 23 and 24 s) shown as open crosses at their delta share. Span 20 to 30 s: alpha 22 %, delta 28 %, mean over the kept windows.

Lesson 216 minYou are hereRead

EEG and rhythms

Read a synthetic EEG by frequency band: alpha rises as the eyes close, blink windows are rejected, and averaging trials recovers a small evoked response.

After this chapter

Where to go next.

The chapters either side, and the rest of Part XI in the library.

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