Abstract: A natural gas detection system is provided for use with a vehicle. A natural gas detector apparatus is mounted to the vehicle so that the vehicle transports the detector apparatus over an are of interest at speeds of up to 20 miles per hour. The detector apparatus includes a transmitter section and a receiver section displaced a preselected distance from each other. The transmitter section has a light source transmitting a light beam to the receiver section forming a beam path therebetween. The apparatus is arranged such that natural gas intercepts the beam path and absorbs representative wavelengths of the light beam. The receiver section receives a portion of the light beam onto an electro-optical etalon for detecting the gas. A method of detecting natural gas is also provided. The method has the steps of providing a vehicle and mounting a natural gas detector apparatus to the vehicle. The detector apparatus has a transmitter section and a receiver section displaced a preselected distance from each other.

Abstract: A signal manifold having a source signal converter coupled to an RF source for converting a source electronic signal from the RF source into an optical signal. The manifold has an optical coupler, having multiple optical fibers, coupled to the first signal converter; and a sink signal converter coupled to the optical coupler. The sink signal converter converts the optical signal from the coupler into a sink electronic signal and conveys that electronic signal to an RF sink.The manifold can be a transmit manifold, or a receive manifold. In addition, a transmit manifold and a receive manifold can be combined to provide a bi-directional signal manifold. The invention herein also provides low-loss asymmetric fiber-optic combiner which includes multiple optical fibers, each fiber having cladding removed from the respective fiber end, exposing the fiber core. The cores are joined together in a predefined configuration and each are optically coupled to a plenum optical fiber.

Abstract: A fiber optic transmitter having a directly modulated laser diode for transmitting a modulated optical signal, a pin diode for providing a pin diode monitor current representing the output power of the laser diode, an optical power source for receiving an optical signal and providing an electrical signal, a power regulator for providing a laser diode driver current which varies with the pin diode monitor current, an amplifier for receiving an RF signal and providing an amplified RF signal to the laser diode, where the laser diode driver current directly modulates the laser diode and biases the transistor in the amplifier.

Abstract: A system for signalling the presence of selected ion species in a gaseous sample of an ion mobility sensor, having a unidirectional field provided between first and second electrodes positioned a selected distance apart. An ionization source generates ions in the sensor and a trigger controller allows ions to enter the region between the first and second electrodes at a time t.sub.1. The ions then arrive at the second electrode at a time t.sub.2. A transimpedance amplifier converts the ion charges to voltage signals. The presence of selected ion species is determined by circuitry that is activated by the trigger controller at t.sub.2. The species are preferably analyzed by directing the amplifier output to an analog to digital converter and then to a digital signal processor. The ions may alternatively be analyzed by generating a logic pulse representing a selected ion species when the amplifier output exceeds a preset value.

Abstract: An improved phased array radar system has a plurality of bias binary fiber optic delay lines each connected between the transmit/receive cells and at least one of signal input means and signal processing means. A plurality of electronic binary delay lines are connected to at least one of the signal input means and the signal processing means and each bias binary fiber optic delay line.

Abstract: A detector for aligning a laser beam has been provided. The detector includes an insulative substrate, and a thermally conductive planar face attached to the substrate. The face is divided into thermally isolated sectors, each sector having the same shape and area. A corresponding thermal sensitive device is provided for each sector. Each sector is in thermal contact with a corresponding one of the thermal sensitive devices, and each thermal sensitive device produces a response proportional to the amount of laser energy impinging thereon to thereby provide indication of the misalignment of the laser beam relative to the transport path.

Abstract: An evoked potential autorefractometry system includes a computer driving an alternating checkerboard mirror stimulus to project a stimulus pattern directly to a patient through a continuously variable focus lens controlled by the computer and which maintains a constant image size on the patient's retina. The evoked potentials produced by the patient are amplified, asychronously filtered both in an analog and digital fashion to allow peak to peak detection of the evoked potentials to determine amplitude. The digital filter includes a 255 point running sum. The peak to peak amplitudes are asychronously digitally filtered using a 16 point running sum to produce an amplitude measure of the evoked potentials. The lens is swept rapidly from one extreme of focus to the other extreme in relatively large steps to determine the area in which the peak amplitude occurs.

Abstract: A low noise, high gain differential amplifier suitable for EEG amplification is constructed in a shielded metal enclosure, preferably on a ground plane circuit board. The amplifier is battery powered to eliminate all possibility of noise from the power system. The amplifier utilizes a pair of operational amplifiers to provide high input impedance for each of two input signals. A differential amplifier generates an internal signal which is filtered and amplified by a pair of bandpass amplifiers and overlapping low pass and high pass amplifiers.

Abstract: A portable acoustic intensity measuring device comprising a pair of electroacoustic transducers at a positioned predetermined distance from one another. The measuring device utilizes analog summing, subtraction, integration and multiplier means for measuring an acoustic intensity vector midway between the two electroacoustic transducers. The acoustic intensity measuring device further comprises error correction means connected in circuit with a preamplifier means and a meter means. The error correction means includes switching means comprising a first switch connected in circuit with the preamplifier and summing means and subtraction means and a second switch connected in circuit with the multiplier and the meter for simultaneously switching the first and second preamplified analog signals at the summing input and subtraction input and for simultaneously switching the polarity of the acoustic intensity signal at the meter.

Abstract: A circuit means in combination with a conventional oxygen ion conductive solid electrolyte cell establishes the cell in a voltage mode for the purposes of measuring excess oxygen and developing a voltage signal indicative thereof, and switching the cell to a current mode of operation in response to an excess combustible environment wherein current drawn by the cell to pump oxygen for combustible reaction with the excess combustibles environment is measured as an indication of the combustibles content of the gas.

Abstract: Method and apparatus for measuring the charge energy available from electrochemical cells (batteries) of the type that exhibits a substantially constant discharge voltage characteristic over its charge life, such as zinc-silver oxide cells. Within several seconds following a brief period of shorting out for reactivation, two to four seconds in the case of zinc-silver oxide cells, short circuit current from the test cell flowing for a period of time just sufficient for complete charging of the internal capacitance of such test cell is sensed, integrated over such period, and used to control display of information as to the charge level of the cell under test.