Patent ID: 9572500
Date: 2017-02-21
CPC Classifications: A61B

Claim:
1. An electronic sphygmomanometer comprising: a cuff that is worn on a measurement area; an inflation and deflation unit that adjusts a pressure applied to the cuff; a plurality of pressure sensors connected to the cuff; a plurality of oscillation circuits, provided in correspondence to the respective plurality of pressure sensors, that output a square wave signal of a frequency based on pressures; an oscillation circuit adjustment circuit having a plurality of input terminals to receive signals from the plurality of oscillation circuits, and having only one output terminal that allows the output of the square wave signal from one of the plurality of oscillation circuits to pass; and a CPU having only one analog input terminal that is configured to accept an input of the square wave signal from the one output terminal of the oscillation circuit adjustment circuit and configured to calculate a blood pressure from the frequency of the square wave signal, wherein the CPU comprises a switching unit that outputs an activation signal that is applied selectively to one of the plurality of oscillation circuits so that when one oscillation circuit is activated by the activation signal, the remaining oscillation circuits are not activated, and wherein the CPU is further configured to determine whether or not an abnormality has occurred in the plurality of pressure sensors, upon comparing the blood pressures obtained from the plurality of oscillation circuits associated with the plurality of pressure sensors, respectively.