Abstract: A circuit for use in respiration type apparatus using a piezoresistive transducer and wherein the temperature effects on system stabilization are minimized and system initialization times are reduced. The circuit comprises a differential sensor amplifier response to the output of the piezoresistive transducer, a dc negative feedback circuit connected to the output of the differential amplifier, an initialization circuit for reducing the initialization time of the circuit, a diode clamp and voltage follower for clamping the voltage output and a voltage comparator for tracking the circuit operating point and switching its output state when a sudden voltage change caused by a patient breath is detected.

Abstract: A circuit for use in respiration type apparatus using a piezoresistive transducer and wherein the temperature effects on system stabilization are minimized. In addition, means are provided to reduce system initialization times. The circuit comprises a differential sensor amplifier response to the output of the piezoresistive transducer, a dc negative feedback circuit connected to the output of the differential amplifier, means for reducing the initialization time of the circuit, circuit means for clamping the voltage output and a voltage comparator for tracking the circuit operating point and switching its output state when a sudden voltage change caused by a patient breath is detected.

Abstract: An electrically conductive diaphragm is sandwiched between a first and second board member. One of said board members has a metallic plate thereon, there being a non conductive spacer having an opening therein separating such board member from the diaphragm. The board members, diaphragm and spacer are joined together to form an integral assembly, the portion of the diaphragm opposite the opening in the spacer being free to move in such opening towards the board member with the metallic plate, motion of the diaphragm away from the spacer being prevented by the other board member. A respiratory gas inlet is provided through the board member with the metallic plate to the opening in the spacer. The diaphragm and metallic plate form a capacitor the capacitance of which is varied in response to the pressure differential between the gas inlet and the atmosphere, the diaphragm only being free to move towards the metallic plate in response to negative pressures (suction) induced during inspiration by a patient.

Abstract: A collision avoidance system adapted for railroad use comprising a track having connected thereto a plurality of first signal transmitters exciting the track by a first control signal within a first frequency bandpass range and a plurality of second signal transmitters interspaced between the first signal transmitters in an alternating arrangement, such second transmitters exciting the track by a second control signal within a second frequency bandpass range. While the first and second control signals are respectively within the first and second bandpass range, individual ones thereof are separated by frequency increments from the other control signals within the corresponding bandpass range such that any beats therebetween are of a relatively high frequency.

Abstract: A guidance system for controlling the path of a boat comprising a first conductor disposed below the surface of water in a first elongated loop and connecting at the terminals thereof across an A.C. source of electrical signal and a second conductor driven in a quadrature with the first conductor and disposed in a second loop partly superposed over the first loop. A first and second orthogonal inductive coil, mounted in the boat along a plane parallel to the loop and a plane normal to the loop plane and substantially parallel to the centerline thereof sense the vertical and horizontal components of the electromagnetic field generated about the conductor loops to produce corresponding induced signals respectively varying in amplitude and phase according to the amplitude of the electromagnetic field and the position thereof.