An Electro-Cardio-Graph (ECG) is a device that records the electrical
activity of the heart. Skin electrodes placed at designated locations on the body
collect ECG measurement information, and from these waveforms different
information on heart condition can be derived.
This paper discusses the design and implementation of a single-channel ECG
(three-electrode) circuit with a bandwidth of (0.5-100) Hz for patient monitoring
purposes. The front end of an ECG must be able to deal with weak signals ranging
from few microvolts to few millivolts. An analogue ECG amplifier is designed and
implemented using instrumentation amplifier (IA) followed by band pass filter
(BPF), then by notch filter (NF) to minimize noise affecting the signal, and a right
leg drive circuit (RLDC). .
The ECG data is recorded and analyzed with greater flexibility using personal
computer. The (ALS 4000) PC-sound card is used as a data acquisition device. The
Matlab program (version 6.5) is employed to acquire data from sound card then
digitally processing the signal in order to display the ECG signal on a PC monitor.