Sunday, August 05, 2007
ECG has an amplitude of only about 1 mV, so to detect it an amplifier is needed. There is a problem, though - electrical noise, or electromagnetic interference (EMI). EMI is generated by many common appliances, such as power lines, fluorescent lights, car ignitions, motors and fans, computers, monitors, printers, TVs and television, and cell phones. When the ECG is amplified, the noise is amplified too, and often swamps the ECG signal. Luckily, the noise is usually of a higher frequency than the ECG. For example, AC hum is 60 Hz, which is above the highest frequency in the ECG (about 20 Hz). So the noise can be reduced by low-pass filtering.
Labels: ECG AMPLIFIER
# posted by Dr. Ulman @ 11:52 PM 
