| abstract |
A blood pressure measurement instrument controlled by a microprocessor has an inflatable cuff, a pump for inflating the cuff, an acoustic sensor and amplifier for processing auscultatory sounds and supplying signals to a microcomputer, a display for displaying blood pressure, and pressure sensor for measuring air pressure in the cuff and supplying signals to the microprocessor. The invention comprises an improved air bleed rate controller for providing a linearized bleed slope reference signal which is compared to an actual cuff pressure signal from the cuff pressure transducer, to control a variable opening bleed valve. The reference signal is applied at the initiation of the bleed control phase through a logic circuit from the microcomputer and a time delay switch. Additional logic provides a bleed valve override signal for closing the valve during the pumping phase and providing dumping of cuff pressure on the completion of blood pressure measurement. |