10.6084/m9.figshare.5792589.v1
Marco Rovetta
Marco
Rovetta
João Fernando Refosco Baggio
João Fernando Refosco
Baggio
Raimes Moraes
Raimes
Moraes
An automatic gain control circuit to improve ECG acquisition
SciELO journals
2018
Biopotential amplifier
QRS detection
Amplitude normalization
AGC
SNR
2018-01-17 02:55:25
Dataset
https://scielo.figshare.com/articles/dataset/An_automatic_gain_control_circuit_to_improve_ECG_acquisition/5792589
<div><p>Abstract Introduction Long-term electrocardiogram (ECG) recordings are widely employed to assist the diagnosis of cardiac and sleep disorders. However, variability of ECG amplitude during the recordings hampers the detection of QRS complexes by algorithms. This work presents a simple electronic circuit to automatically normalize the ECG amplitude, improving its sampling by analog to digital converters (ADCs). Methods The proposed circuit consists of an analog divider that normalizes the ECG amplitude using its absolute peak value as reference. The reference value is obtained by means of a full-wave rectifier and a peak voltage detector. The circuit and tasks of its different stages are described. Results Example of the circuit performance for a bradycardia ECG signal (40bpm) is presented; the signal has its amplitude suddenly halved, and later, restored. The signal is automatically normalized after 5 heart beats for the amplitude drop. For the amplitude increase, the signal is promptly normalized. Conclusion The proposed circuit adjusts the ECG amplitude to the input voltage range of ADC, avoiding signal to noise ratio degradation of the sampled waveform in order to allow a better performance of processing algorithms.</p></div>