[Standardization of the resistance of grounded electrocardiographs with patient circuits ground-insulated to electrical cophase interferences from an external main].

The possibility of simulating conditions for electrocardiographic interferences examination by current and voltage generators is shown. These two models allow it to adopt for appraising the resistance of electrocardiographs to outside cophasic electric interferences any one of the two equivalent parameters, viz. "the equivalent resistance of cophasic interferences" and "coefficient of cophasic rejection". The said parameters represent the relation between the differential value of the interferences voltage at the inlet of the electrocardiograph and the interferences current and interferences voltage of the current generators and of the interverences voltage that produced the former, respectively. The required magnitudes for these parameters have been found, namely less than or equal to 14 Om and 0.5-10(-6) V. For practical purposes it is preferable to use the coefficient of cophasic rejection.