Abstract: Disclosed is a method and apparatus for discriminating pace pulse tails generated by signals discriminated from QRS complexes by mathematically ascertaining that the signal following the pace pulse peak has an exponential decay. The invention ascertains whether or not the waveform decays exponentially through application of a mathematical equation.

Abstract: A modular housing assembly is provided for two incompatible circuits, for example an RF circuit and a digital circuit, mounted on the same printed circuit board. The housing assembly has a base member and a cover member which are meshed to form two double walled compartments separated by a double conducting wall. The circuit board has at least one bridge physically and electrically connecting the two cicuits on the board which bridges pass through corresponding channels in the separating wall and each contain a matrix of plated through holes which operate to extend the wall through the bridge. Interconnecting wiring is woven through the holes to pass desired signals. Filters are provided between the interconnecting wiring and each circuit to eliminate conductive interference. Conductive gaskets are provided at all junctions of the separating wall with a housing member or with a circuit board to further reduce radiation leakage between the circuits.

Abstract: A system and method are shown for performing cool, on-column sample injection into a chromatographic device having a capillary column which injection is achieved through the use of a syringe having a needle. The column diameter is minimized by the provision of an inlet assembly connected to the inlet end of the column, a sealing member disposed in the inlet assembly, for forming a fluid tight seal in the inlet end when the sample is injected onto the column to prevent the sample from escaping and for reducing the effective length of the needle at the point of insertion of the needle into the column and a guide member for reducing the effective length and for supporting the needle during insertion into the column. A temperature controller for controlling the temperature of the column in the region where the sample is injected is also disclosed. The sealing member is shown to include an elastomeric member and further the system includes a mechanism for continuously cooling the elastomeric member.

Abstract: A method and apparatus for controlling measurement repeatability in spectrochemical analysis which analysis utilizes a plasma source is shown to include a plasma generator for providing energy to the plasma source to sustain plasma, a sensor for sensing the operating temperature of the plasma generator and a temperature controller for controlling the operating temperature of the plasma generator in response to the temperature sensed by the sensor. The temperature controller controls the operating temperature of the plasma generator either within a temperature range, such as between 100.degree. C. or at a set point temperature. In the case of a magnetron having heat conductive fins as the plasma generator, the sensor senses the temperature of at least one of said fins and the temperature controller includes a fan directed to move air across the fins and a speed controller for controlling the speed of the fan in response to the sensed temperature of the fins.

Abstract: A solenoid driven valve is disclosed which is adaptable for controlling the introduction of a high pressure fluid into a fluid trapping assembly having an absorption column topped with an annular orifice expansion nozzle. The valve has an inlet port to introduce high pressure fluid, an axially moving solenoid driven pin which engages means to restrict fluid flow into said column. A diaphragm is located within the valve to direct fluid into the column and which separates the fluid in a region of high pressure from ambient pressures.

Abstract: A pressure transducer having a first pair leads for receiving an excitation voltage and a second pair of leads between which it can supply a voltage corresponding to a pressure applied to it is provided with means for placing at least one electrical load between said first pair of leads. The leads are connected to a pressure monitor having means for indicating the pressure represented by the voltage between said second pair of leads and means for indicating an alarm condition when said signal indicates a pressure outside of a given limit. The monitor has local means for disabling the alarm indicating means and means for setting the indicated pressure to zero. The monitor also has means responsive to a first given current in said first pair of leads for disabling said means for indicating an alarm and means responsive to a second given current in said first pair of leads for causing said means for indicating pressure to indicate a zero pressure.

Abstract: Apparatus and methods are disclosed for performing a chromatographic separation of a given compound utilizing programmed temperature and mass flow wherein the compound is injected into a pressurized carrier gas and passed through a column and wherein a portion of the column is subjected to a temperature profile, by determining the pressure of the carrier gas and generating a pressure information signal representative of such pressure, storing desired carrier gas mass flow information and temperature profile information, and controlling the pressure of the carrier gas in response to the mass flow information, the temperature profile information and the pressure information signal, so that as the temperature profile information changes with time, the desired mass flow of carrier gas at a corresponding time is maintained by controlling the pressure of the carrier gas.

Abstract: In a system for analyzing a chemical sample by chromatographic separation of said sample into components a method and apparatus are provided for heating the mobile phase to a desired temperature prior to exiting the restrictor, while maintaining the density of the mobile phase at a desired level. Such heating and density maintenance being provided by the combination of a restrictor having a minimal taper length and a temperature zone immediately prior to the outlet end of the restrictor, which temperature zone has a minimum length. A second temperature zone spaced upstream from the first zone, and an intermediate thermally conductive member between the first and second zones can be provided as an alternative embodiment for establishing a thermal gradient. As the mobile phase passes through the second zone, the intermediate conductive member, and the first zone, the mobile phase is subjected to a thermal gradient.

Abstract: A pneumatic connector for an automated non-invasive blood pressure monitor having a connector body (1) containing two oppositely arranged hollow cavities (8) for insertion of a differential pressure sensor in each cavity. The hollow cavities are connected by a bore (10) which is in connection with the main airway (6,7) in the connector body (1). Additionally, both differential pressure sensors have differential pressure sensors which are connected to the ambient air via a secondary airway.

Abstract: A microwave resonant cavity for a spectroscopic light source includes a housing having therein a chamber formed by side walls and a cylindrical outer wall. The side walls having aligned openings therethrough which are on the longitudinal axis of the outer wall. A refractory tube which is adapted to contain a gaseous plasma extends through the aligned openings and across the chamber in the housing. The portion of the side walls of the chamber adjacent the openings are closer together than the remaining portions of the side walls so that the chamber has a first portion around the refractory tube which is narrower than a second portion of the chamber around the first portion. A coupling loop is electrically coupled to a side wall of the chamber within the second portion of the chamber and is connector to a coaxial connector which extends through the outer wall of the housing to deliver microwave power to the chamber.

Abstract: In a system for analyzing a chemical sample by chromatographic separation of said sample into components a method and apparatus are provided for maximizing detector resolution and minimizing duration by maintaining the linear velocity of the mobile phase at a desired level by affecting the viscosity and density characteristics of the mobile phase as it passes through a restrictor by programming the restrictor temperature.

Abstract: A monitor for the automated non-invasive measurement of a patient's blood pressure comprising apparatus for automatically inflating and deflating a cuff which is to be applied around a patient's extremity, first and second pressure sensors coupled to the airway of said cuff, each providing an electronic signal indicative of cuff pressure, and a processor responding to the signals obtained by said pressure sensors for stopping the inflation of the cuff when a maximum cuff pressure is reached, and for calculating the blood pressure from the oscillations of the pressure signal. A memory is connected to said processor in which calibration values indicating the pressure related to the electronic signals provided by each of said two pressure sensors are stored.

Abstract: Apparatus and methods are disclosed for performing a chromatographic separation of a given compound wherein the compound and a carrier gas are passed through an injection port and onto a column and wherein a portion of the column is contained in an oven. The apparatus and method are shown to include a first heater for heating the injection port in response to a first control signal, a first temperature sensor for sensing the temperature of the injection port and for generating a first temperature signal representative of the temperature of the injection port, a second heater for heating the oven in response to a second control signal, a second temperature sensor for sensing the temperature of the oven and for generating a second temperature signal representative of the temperature of the oven and a cooling member for simultaneously cooling the injection port and the column. The cooling member can include various conduit arrangements for directing a flow of cryogen fluid.

Abstract: A method for resolving severely overlapped chromatogram peaks using Jansson's iterative deconvolution method is disclosed. The method requires only a knowledge of the impulse response function of the chromatographic apparatus and maximum peak height. A high degree of resolution is achieved without significantly degrading the chromatogram signal to noise ratio.

Abstract: Continuous production of ultra-pure helium and neon gases is achieved by utilizing the fact that these gases have the highest ionization and excitation potentials of all chemical substances. The helium/neon gas stream to be purified is excited by, for example, a corona discharge not only to directly ionize some of the impurities but also to produce noble gas ions and metastable atoms. These ions and metastables subsequently collide with and ionize impurities. A polarizing field is used to draw the impurity ions out of the main gas flow and into a subsidiary flow bled from the main flow. In a preferred embodiment, the polarizing field is established between a central rod-shaped anode (13) and a surrounding tubular cathode (10) through which the main gas flow passes. The cathode is made of a porous material so that positive impurity ions can be removed by the radial outwards flow of gas therethrough.

Abstract: A circuit for generating jitter includes a mixer which mixes a jittered signal from a jitter generator with the output of a variable frequency oscillator to produce a broadband jittered output. A preferred form of the circuit uses a double frequency translation technique in which the output from a reference oscillator is applied to a jitter generator and to a first frequency translation device to translate a variable input frequency to an intermediate frequency. The jittered signal and the intermediate frequency signal are then applied to a second frequency translation device to produce a jittered output at the variable input frequency.

Abstract: An apparatus for producing a high voltage comprising a high voltage output means operating on a system common voltage, and a floating power supply means operating on the output voltage from the high voltage output means which is at a floating common potential.

Abstract: A computer input device removably mounted to a keyboard is disclosed. A bar, which may be slightly longer than the width of the keyboard, is slidably mounted beneath the keyboard. The bar is slidable from a first position in which one end of the bar extends beyond the side of the keyboard to a second position in which the other end of the bar extends beyond the other side of the keyboard. An input device, such as a trackball, is removably attached, for example, by hook and loop fasteners, to the end of the bar which extends beyond the side of the keyboard. To move the device to the other side of the keyboard, the device is lifted off the end of the bar, the bar is slid under the keyboard until the other end extends beyond the other side of the keyboard, and the device is attached on the other end of the bar. The removable mount of the present invention thus accommodates left and right side mounting, eases the switching from side to side, and takes up minimum space.

Abstract: A method and apparatus for reducing noise in a light sensing circuit having a photodiode array coupled to a charge amplifier through a field effect transistor transfer switch. Thermal noise generated by the transfer switch is combined with image signals inputted to the charge amplifier resulting in an outputted noisy image signal. The invention eliminates this noise by taking two consecutive readings of the charge amplifier output, one before and one after closing the transfer switch and after opening it. The thermal noise generated by the transfer switch, and added to the next reading of the charge amplifier output, is equal to the difference between these two readings. Once stored, this difference can be subtracted from the previously mentioned "next reading", resulting in the elimination of this noise term.

Abstract: A pumping apparatus for delivering liquid at a high pressure, in particular for use in liquid chromatography, comprises two pistons (10, 20) which reciprocate in pump chambers (7,18), respectively. The output of the first pump chamber (7) is connected via a valve (13) to the input of the second pump chamber (18). The pistons are driven by linear drives (30,31), e.g., ball-screw spindles. The stroke volume displaced by the piston (10) is freely adjustable by corresponding control of the angle by which the shaft of the drive motor (36) is rotated during a stroke cycle. The control circuitry is operative to reduce the stroke volume when the flow rate which can be selected by user at the user interface (42) is reduced, thus leading to reduced pulsations in the outflow of the pumping apparatus. The pumping apparatus can also be used for generating solvent gradients when a mixing valve (2) connected to different solvent containers (A,B,C,D) is coupled to the input of the pumping apparatus (FIG. 1).