A single chip computer control system of electrocardiac analog patient was introduced in this paper. Electrocardiogram is showed on the monitor by controlling the keyboard and at the same time change of the cardiagram is managed digitally and displayed on electrocardiac monitor. There are about more than fourty typical cardiograms. All the change of the patient′s cardiogram before and after defibrillation and recovering can be simulated automatically. Strong interference is bring about by defibrit has been...