A precision ECG signal generator providing full Lead II QRS amplitude variability and an accurate timing profile

This paper reports the design and development of a precision ECG signal generator intended for use in test and calibration of electrocardiographic equipment, ECG signal processing systems and as a cardiac teaching tool. It generates a Lead II signal which maintains the timing and profile characteristics of a Lead II electrocardiograph signal across a range of heart rates between 45 and 185 bpm in 1 bpm steps. The QRS amplitude can be adjusted in 1 microV increments from 100 microV to 10 mV. The up-slope of the QRS can be set between 15 ms and 45 ms with 1 ms resolution. The P and T wave amplitudes can be adjusted as a 1-100% scaling of the QRS complex amplitude with a 1% resolution. A color LCD with touch screen capability provides the user with facilities for inputting parameters, viewing the output wave parameters and a graphical representation of the resulting output waveform. The signal generator outputs a precision differential signal via a digital to analogue stage which has been designed using low noise techniques to produce accurate signals at the lower end of the QRS amplitude range.