Apparatus and method for measuring blood pressure using linearly varying air pressure

A method for measuring the blood pressure using linearly varying air pressure, comprising:

• (a) injecting air into a compression unit until a reference pressure value is reached;
• (b) calculating a current pressure value of the compression unit from a pressure signal output from an analog-to-digital converter (ADC), and a linear pressure for the current pressure value;
• (c) determining whether the current pressure value is greater than the linear pressure;
• (d) if the current pressure value is determined to be greater than the linear pressure, increasing a rate of dropping pressure of the compression unit;
• (e) if the current pressure value is determined to be equal to or less than the linear pressure, decreasing the rate of dropping pressure of the compression unit;
• (f) after (d) or (e), determining whether a number of current pressure values calculated is equal to fs×t, where fs denotes a sampling frequency of the analog-to-digital converter and t denotes a period of time required until a maximum pressure Pmax of the compression unit drops to a minimum pressure Pmin;
• (g) if the number of current pressure values is determined to be less than fs×t, then changing a variable i denoting the order of the pressure signal input from the analog-to-digital converter and proceeding to (b);
• and
• (h) if the number of current pressure values is determined to be equal to fs×t, determining the blood pressure using the current pressure values in a quantity equal to fs×t.