Abstract: A compact mobile high-frequency Antenna that quickly and quietly self-adjusts to minimize Voltage Standing Wave Ratio (VSWR). Includes a compact tuning coil and a rolling contact. A Reentrant cap serves as a capacitive top hat. A spiral cut enhances the efficiency is this very short antenna. A tough insulating tube covers the antenna to serve as a radome protect the user from RF burns. The use of rolling contacts on a smooth inside diameter of the tuning coil greatly reduces the force to move the contactor as well as the acoustical noise generated when tuning. A controller drives a servo motor to position the contactor to the optimal position within the tuning coil and selects the impedance to connect between the unused end of the tuning coil and the feed point of the antenna to optimize VSWR.

Abstract: Absolute multi-turn position sensing integrated within the structure of a hybrid stepper motor implemented by sharing the magnetic structure of the motor with the sensing means. An alternating magnetic field is obtained from a single magnet within the stepper motor rotor by use of alternating flux paths directed to large Barkhausen jump effect sensing elements. Pulses generated from the large Barkhausen sensing are decoded electronically and stored in a non-volatile memory to absolutely locate the motor position within a fraction of 1 electrical cycle of the motor over an arbitrary range. This coarse position sensing can optionally be extended by use of a higher resolution absolute within-electrical-cycle sensing means to provide integrated high resolution position sensing over an arbitrary number of revolutions.

Abstract: Absolute multi-turn position sensing integrated within the structure of a hybrid stepper motor implemented by sharing the magnetic structure of the motor with the sensing means. An alternating magnetic field is obtained from a single magnet within the stepper motor rotor by use of alternating flux paths directed to large Barkhausen jump effect sensing elements. Pulses generated from the large Barkhausen sensing are decoded electronically and stored in a non-volatile memory to absolutely locate the motor position within a fraction of 1 electrical cycle of the motor over an arbitrary range. This coarse position sensing can optionally be extended by use of a higher resolution absolute within-electrical-cycle sensing means to provide integrated high resolution position sensing over an arbitrary number of revolutions.

Abstract: An integrated motor and position sensor achieves motion between a moving portion and a stationary portion by electrically energizing poles to interact with magnetics respectively on the moving and stationary portions. The position sensor includes a plurality of sensing coils placed to intercept the magnetic flux between a plurality of the poles and the magnetics. The outputs from these coils are fed to a microprocessor DSP through an internal or external A/D converter. The microprocessor or DSP decodes the measured voltages using resolver strategies to produce a position, velocity or acceleration measurement.

Abstract: An AC synchronous motor, also known as a stepper motor, uses its magnetics and drive coils to produce both motion and excitation for sets of position sensing coils. Each drive phase is equipped with one or more sensing coils, which may be differentially wound, with the coils configured to act as secondaries of a linear variable differential transformer (LVDT). The primary of the so-formed LVDT is the motor drive winding. The outputs from these coils are fed to a microprocessor or DSP through an internal or external A/D converter. The microprocessor or DSP decodes the measured voltages using resolver strategies to produce a position measurement. An alternate mode of operation uses these same coils to form a variable reluctance resolver. This alternative mode of operation could be used for sensing coarse position while the motor drive is not energized.

Abstract: An integrated motor and position sensor achieves motion between a moving portion and a stationary portion by electrically energizing poles to interact with magnetics respectively on the moving and stationary portions. The position sensor includes a plurality of sensing coils placed to intercept the magnetic flux between a plurality of the poles and the magnetics. The outputs from these coils are fed to a microprocessor or DSP through an internal or external A/D converter. The microprocessor or DSP decodes the measured voltages using resolver strategies to produce a position, velocity or acceleration measurement.

Abstract: An AC synchronous motor, also known as a stepper motor, uses its magnetics and drive coils to produce both motion and excitation for sets of position sensing coils. Each drive phase is equipped with one or more sensing coils, which may be differentially wound, with the coils configured to act as secondaries of a linear variable differential transformer (LVDT). The primary of the so-formed LVDT is the motor drive winding. The outputs from these coils are fed to a microprocessor or DSP through an internal or external A/D converter. The microprocessor or DSP decodes the measured voltages using resolver strategies to produce a position measurement. An alternate mode of operation uses these same coils to form a variable reluctance resolver. This alternative mode of operation could be used for sensing coarse position while the motor drive is not energized.

Abstract: Health hazards to persons from prolonged exposure to high power fields, and specifically to X-ray radiation in such fields in the etiology of leukemia and other forms of cancer, are eliminated by preventive monitoring to detect corona indicating existence of ionization fields, and by coating cable and support structures with a material comprising low molecular number (Z) elements in carriers such as polymers in amorphous or molded forms to absorb energy and prevent X-ray formation. Shields of relatively high Z elements in polymer bases are provided to confine potential X-ray sources due to arcing at switch contacts.

Abstract: An all digital control method for motor drivers eliminates physical motor current sensing. The motor and the driver are modeled to estimate the actual current and the estimated current is used to perform motor control. This provides simplified driver circuitry. Driver non-linearity due to driver dead time may be compensated and minimum driver on times are accommodated while providing good waveform fidelity, minimized motor heating and increased motor system damping.

Abstract: An apparatus is provided for detecting the pressure of a fluid. The device includes a device for detecting the pressure of a fluid comprising (a) a housing; (b) a first conduit disposed within the housing, having an open inlet end, and an outlet end; (c) a second conduit disposed within the housing having an inlet end and an open outlet end; and (d) a pressure detector disposed within the housing in abutment with the outlet end of the first conduit and the inlet end of the second conduit, such that the pressure detector is in direct operative contact with a fluid flowing within the first and second conduits. Typically, the pressure detector is a pressure transducer. Preferably, the pressure transducer is located within the body, such that the first conduit is disposed at an angle with respect to the pressure sensitive surface of the transducer, the angle being between about 50.degree. and about 75.degree., most preferably between about 65.degree. and about 70.degree..

Abstract: A technique and circuit for measuring direct current flowing through a conductor at a high voltage employs a capacitor connected in series with the conductor, and a neon lamp connected in parallel with the capacitor. The series connected capacitor and conductor are connected to a high voltage source such that the current flowing through the series connected capacitor and conductor charges up the capacitor. Since the capacitor and the neon lamp are connected in parallel, the voltage across the electrodes of the neon lamp follows the voltage across the capacitor. When the voltage across the electrodes of the neon lamp reaches the lamp's ignition voltage, the neon lamp fires, and discharges the capacitor until the voltage across the electrodes of the neon lamp falls to the lamp's extinction voltage. The light signal generated by the neon lamp is picked up by a fiber optic cable and transmitted to a remote receiver for processing.

Abstract: An automated analytical system module design essentially electrically isolates modular elements within the analyzer system with inter-module communications provided via packet-based communications. The modules may include a motor controller which estimates motor temperature to enable high initial torque with motor failure prediction and detection. The modules in such a system can be identified on serial communications loops by a module reset and count-off process.

Abstract: A liquid level sensing system comprising a probe and a reactive element carried by the probe. The reactive element forms a portion of a tuned circuit in a voltage-controlled oscillator. The output of the voltage-controlled oscillator is compared to a fixed frequency reference signal and a frequency/phase detector generates a signal indicative of any difference. The frequency/phase detector output is applied to the voltage-controlled oscillator to maintain the output frequency of the oscillator at the frequency of the reference signal. The output of the frequency/phase detector is also differentiated to develop a pulse when the frequency/phase detector output signal varies rapidly, indicating initial contact between the probe and the surface of a liquid held within a container.