Abstract: A motor control system that reduces noise while reducing power requirements but providing sufficient torque. A one-phase-on drive mode modified to microstep between “one phase on” positions is used to accelerate the motor in a non-linear manner to a maximum speed. The microstep drive modes have a constant period, and the step rate of the motor is increased by decreasing the number of microsteps in succeeding steps of the motor. A modified full step waveform maintains the motor at the maximum speed, where the current to one winding of the step motor changes polarity within one motor step while the other remains approximately constant providing increased smoothness in the drive and reduced noise. The polarity changes in accordance with the inductance and the compliance voltage of the motor.

Abstract: An ultrasound transducer comprises a sheath body constructed from a nonconductive material. The sheath body is configured to be installed over a medical device. A piezoelectric copolymer transducer is held snugly against the medical device by the sheath body when the ultrasound transducer is installed over the medical device. The piezoelectric copolymer transducer transduces incident ultrasound signals into corresponding electric signals. A ground conductor is coupled to a first surface of the piezoelectric copolymer transducer. A signal conductor is coupled to a second surface of the piezoelectric copolymer transducer and conducts the corresponding electric signals to a proximal end of the medical device.

Abstract: A motor control system that reduces noise while reducing power requirements but providing sufficient torque. A one-phase-on drive mode modified to microstep between “one phase on” positions is used to accelerate the motor in a non-linear manner to a maximum speed. The microstep drive modes have a constant period, and the step rate of the motor is increased by decreasing the number of microsteps in succeeding steps of the motor. A modified full step waveform maintains the motor at the maximum speed, where the current to one winding of the step motor changes polarity within one motor step while the other remains approximately constant providing increased smoothness in the drive and reduced noise. The polarity changes in accordance with the inductance and the compliance voltage of the motor.

Abstract: An ultrasound transducer comprises a sheath body constructed from a nonconductive material. The sheath body is configured to be installed over a medical device. A piezoelectric copolymer transducer is held snugly against the medical device by the sheath body when the ultrasound transducer is installed over the medical device. The piezoelectric copolymer transducer transduces incident ultrasound signals into corresponding electric signals. A ground conductor is coupled to a first surface of the piezoelectric copolymer transducer. A signal conductor is coupled to a second surface of the piezoelectric copolymer transducer and conducts the corresponding electric signals to a proximal end of the medical device.

Abstract: A wireless digital launch or firing system has a transmitter unit that can transmit separate RF signals representing an “enable” code sequence and an “actuate” code sequence, and a receiver unit which decodes the “enable” code sequence to enable receipt of the “actuate” code sequence, and decodes the “actuate” code sequence to actuate launching or firing. A digital processor receives the code sequences from a receiver circuit and compares them to stored digital code sequences. A memory latch maintains a normally-off primary switch in an “on” condition when the “enable” signal is received. A normally-off secondary switch is set to an “on” condition when the “actuate” signal is received.

Abstract: A system for noninvasively continuously monitoring arterial blood pressure includes a tissue stress sensor that has a continuous diaphragm for sensing stress within tissue adjacent a preselected artery caused by arterial pulsations within that artery. The stress sensitive diaphragm is coupled with electromechanical means for producing electrical signals that represent the stress within the tissue that is communicated to the sensor. These signals are then processed electronically in order to yield an output that is indicative of the arterial blood pressure of the preselected artery. The disclosed system includes methods of operation for determining blood pressure while maintaining a preselected artery in an optimum applanation state and an off-optimum applanation state.

Abstract: An ultrasound transducer comprises a sheath body constructed from a nonconductive material. The sheath body is configured to be installed over a medical device. A piezoelectric copolymer transducer is held snugly against the medical device by the sheath body when the ultrasound transducer is installed over the medical device. The piezoelectric copolymer transducer transduces incident ultrasound signals into corresponding electric signals. A ground conductor is coupled to a first surface of the piezoelectric copolymer transducer. A signal conductor is coupled to a second surface of the piezoelectric copolymer transducer and conducts the corresponding electric signals to a proximal end of the medical device.

Abstract: A motor control system that reduces noise while reducing power requirements but providing sufficient torque. A one-phase-on drive mode modified to microstep between “one phase on” positions is used to accelerate the motor in a non-linear manner to a maximum speed. The microstep drive modes have a constant period, and the step rate of the motor is increased by decreasing the number of microsteps in succeeding steps of the motor. A modified full step waveform maintains the motor at the maximum speed, where the current to one winding of the step motor changes polarity within one motor step while the other remains approximately constant providing increased smoothness in the drive and reduced noise. The polarity changes in accordance with the inductance and the compliance voltage of the motor.

Abstract: A motor control system that reduces noise while reducing power requirements but providing sufficient torque. A one-phase-on drive mode modified to microstep between "one phase on" positions is used to accelerate the motor in a non-linear manner to a maximum speed. The microstep drive modes have a constant period, and the step rate of the motor is increased by decreasing the number of microsteps in succeeding steps of the motor. A modified full step waveform maintains the motor at the maximum speed, where the current to one winding of the step motor changes polarity within one motor step while the other remains approximately constant providing increased smoothness in the drive and reduced noise. The polarity changes in accordance with the inductance and the compliance voltage of the motor.

Abstract: A system for noninvasively continuously monitoring arterial blood pressure includes a tissue stress sensor that has a continuous diaphragm for sensing stress within tissue adjacent a preselected artery caused by arterial pulsations within that artery. The stress sensitive diaphragm is coupled with electromechanical means for producing electrical signals that represent the stress within the tissue that is communicated to the sensor. These signals are then processed electronically in order to yield an output that is indicative of the arterial blood pressure of the preselected artery. The disclosed system includes methods of operation for determining blood pressure while maintaining a preselected artery in an optimum applanation state and an off-optimum applanation state.

Abstract: A device for mounting a tonometry sensor upon a patient's wrist includes a base portion that is specifically adapted to generally conform to the patient's wrist while providing a stable placement of the tonometry sensor relative to a preselected artery. A sensor housing is movably mounted upon the base portion and configured such that the mounting device has an essentially equal thickness at each end of the device. A strap member is provided for releasably securing the mounting device to a patient's wrist. The mounting device facilitates more accurate, non-invasive blood pressure measurement by providing a stable placement of the tonometry sensor relative to the tissue overlying a preselected artery at a measurement location and, further, limits undesirable movement by the patient to thereby reduce undesirable error in the blood pressure measurement.

Abstract: A drive member of a peristaltic pumping mechanism includes a disk that rotates with the drive member and has two transparent sectors and two opaque sectors alternating with the transparent sectors. As a stepper motor rotates the drive member to pump fluid, a single optical sensor senses the disk and provides signals indicative of whether a transparent sector or opaque sector is being detected. A processor counts the number of motor steps in the detected transparent or opaque sector and based on the number of counted steps in a type of sector detected or the number of steps counted when a state change to the other type of sector occurs, determines the motor position. In another aspect, the position disk is integrally formed as a single piece with the cams and cam shaft of a pumping mechanism.

Abstract: A tissue contact stress sensing system incorporates a semiconductor assembly and a continuous diaphragm to noninvasively determine the intra-arterial blood pressure of a patient. The system comprises a continuous diaphragm placed against a patient's tissue which covers an underlying artery. The semiconductor assembly is placed in close proximity to and spaced apart from the diaphragm for directly irradiating the diaphragm with electromagnetic radiation and receiving a portion of the electromagnetic radiation which is reflected from the continuous diaphragm. The disclosed system also utilizes a technique for minimizing the system errors associated with temperature drift and aging of the sensor.

Abstract: A wrist mount apparatus for placing a tissue stress sensor in operative engagement with the tissue overlaying an artery of interest is disclosed for use in a system for noninvasively determining the intra-arterial blood pressure of a patient. The wrist mount apparatus comprises a base portion and a transducer platform which is pivotally and slidingly engaged to the base portion. This arrangement allows the apparatus to be used on either the right or the left wrist of the wearer. A force overload system is provided whereby the wearer is protected from excessive forces applied to the wrist tissue by the apparatus used to applanate the artery. A quick disconnect feature allows the tissue stress sensor to be removed from the wrist mount apparatus without necessitating the use of tools.

Abstract: A tissue contact stress sensing system incorporates a semiconductor assembly and a continuous diaphragm to noninvasively determine the intra-arterial blood pressure of a patient. The system comprises a continuous diaphragm placed against a patient's tissue which covers an underlying artery. The semiconductor assembly is placed in close proximity to and spaced apart from the diaphragm for directly irradiating the diaphragm with electromagnetic radiation and receiving a portion of the electromagnetic radiation which is reflected from the continuous diaphragm. The disclosed system also utilizes a technique for minimizing the system errors associated with temperature drift and aging of the sensor.

Abstract: A control apparatus for controlling the temperature of an environmental chamber within which a device is tested for thermal characteristics employs a pair of control elements connected in cascade. The first element produces a required air temperature in response to a desired temperature and to the temperature of the device; the second produces a temperature set point in response to the required and actual air temperatures. Possible stress on the device is avoided by limiting the range of required air temperature. Response is accelerated by a pass-through circuit, parallel to the first element, which responds to a change in the desired temperature by adding to the required air temperature of value proportional to the change.