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ELECTROCARDIOGRAPH LEAD DISTRIBUTION AND CONTACT TESTING APPARATUS

  • US 3,757,778 A
  • Filed: 01/13/1971
  • Issued: 09/11/1973
  • Est. Priority Date: 01/13/1971
  • Status: Expired due to Term
First Claim
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1. In electrocardiograph apparatus, a distributor having a plurality of input terminals for receiving electrical signals generated at selected positions on a patient under examination, a plurality of input leads terminating in electrodes adapted to be placed into contact with the patient and connected to said terminals, buffer amplifier means associated with said leads for accepting a high imput impedance signal from the patient and for converting it to a low output impedance signal, extended cable means for connecting the low output impedance signals from said distrubutor to remote amplifying and recording means, a driven ground circuit including means for sensing induced voltages in the patient and means responsive to said last named means for introducing a compensating voltage to one patient electrode whereby the voltage of the patient is kept zero relative to ground, and further in which said means for sensing induced voltages in the patient consists of a filter circuit selectively sensitive to low frequency signals and insensitive to high frequency signals, a differential output for receiving signals from said filter circuit, a ground sensing means for providing a second input to said differential amplifier.

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