The Charles Stark Draper Laboratory, Inc.

Northeastern University

Paul A Ward

Marc Steven Weinberg

Anthony S Kourepenis

James S Pringle, Jr

James Alan Bickford

Amy Elizabeth Duwel

Louis Kratchman

Eric M Hildebrant

Stephen P Smith

William David Sawyer

Farhad Zarinetchi

Daniel Kenneth Freeman

Warner George Harrison

Stephanie Lynne Golmon

Michael Kishinevsky

Ronald Steven McNabb, Jr

Daniel Joseph Guyon

Richard David Elliott, Iii

William A Lenk

Lance C Niles

Matthew Soucy

Max Lindsay Turnquist

Jonathan Jay Bernstein

Matteo Rinaldi

Eugene H Cook

Nicol E McGruer

John Joseph LeBlanc

Steven T Cho

Richard D Elliott

Ralph E Hopkins, Iii

Peter A Welling

Robert A Bousquet

William P Kelley

John J Le Blanc

Kasey Russell

Shida Iep Martinez

Harold Ralph Haley

Joseph G Walsh

A tuning fork sensor system places a controlled bias on the proof-mass drive-axis electrodes to cancel the quadrature charge. Also, its charge amplifiers employ a field-effect transistor biased slightly into the triode region so that it behaves as a very large value resistor. In addition, it uses a phase-locked loop having a special loop filter in order to optimize performance by rejecting off-frequency drive feedthrough to the motor pick-off while resulting in very low phase wander for the demodulation references.

Method and system for control and readout of tuning fork gyroscope

A control circuit for an electrostatic machine includes a current source or sink, an inductor, a switching network coupled between the current source or sink and the electrostatic machine, and between the inductor and the electrostatic machine. A controller is configured to automatically cause the switching network to connect the current source or sink to the electrostatic machine each half-cycle of a periodically alternating polarity. At each polarity alternation, the electrostatic machine is isolated from the current source or sink for a first period of time. At each polarity alternation, the inductor is connected to the electrostatic machine for a second period of time while the electrostatic machine is isolated from the current source or sink, and then disconnect the inductor from the electrostatic machine.

High-power electrostatic machines

Aspects are generally directed to a compact and low-noise electric field detector, methods of operation, and methods of production thereof. In one example, an electric field detector includes a proof mass, a source of concentrated charge coupled to the proof mass, and a substrate having a substrate offset space defined therein, the proof mass being suspended above the substrate offset space. The electric field detector further includes a sense electrode disposed on the substrate within the substrate offset space and proximate the proof mass, the sense electrode being configured to measure a change in capacitance relative to the proof mass from movement of the proof mass in response to a received electric field at the source of concentrated charge. The electric field detector includes a control circuit coupled to the sense electrode and configured to determine a characteristic of the electric field based on the measured change in capacitance.

Miniature electric field detector

Provided is a Precision Voltage Reference (PVR). In one example, the PVR includes a resonator having an oscillation frequency, the resonator including a first proof-mass, a first forcer located adjacent a first side of the first proof-mass, and a second forcer located adjacent a second side of the first proof-mass. The PVR may include control circuitry configured to generate a reference voltage based on the oscillation frequency of the resonator, at least one converter configured to receive the reference voltage from the control circuitry, provide a first bias voltage to the first forcer based on the reference voltage, provide a second bias voltage to the second forcer based on the reference voltage, and periodically alter a polarity of the first and second bias voltages to drive the oscillation frequency to match a reference frequency, and an output configured to provide the reference voltage as a voltage reference signal.

Radiation-hard precision voltage reference

An environmental physical sensor is provided that includes a power input terminal, a sensor output terminal, and a resonant switch. The resonant switch includes a mechanical element that is responsive to an environmental stimulus and is coupled to an electrical switch. The electrical switch is operable between an open position and a closed position and electrically connects the power input terminal to the sensor output terminal when in the closed position. The mechanical element is configured to intermittently actuate the electrical switch into the closed position responsive to the environmental stimulus.

Zero power sensors

According to one aspect, embodiments herein provide a PVR comprising a resonator having an oscillation frequency, the resonator comprising at least one proof-mass, a mechanical reference, at least one drive plate located adjacent a first side of the at least one proof-mass, and at least one sense plate located adjacent a second side of the at least one proof-mass, a voltage source coupled to the drive and sense plates, a reference oscillator configured to provide a reference signal having a reference frequency to the voltage source; and an output, wherein the voltage source is configured to provide a bias voltage signal to the at least one drive and at least one sense plates of the resonator to drive the oscillation frequency of the resonator to match the reference frequency, and wherein the bias voltage signal is also provided to the output of the PVR as a voltage reference signal.

Determining linear modulator dynamics in an interferometric fiber-optic gyroscope may be accomplished by applying a stimulus at a point within the gyroscope, observing a response in an output of the gyroscope, and determining, from the observed response, the linear modulator dynamics.

Determining and compensating for modulator dynamics in interferometric fiber-optic gyroscopes

Interference in a rotation rate detector signal of an interferometric fiber-optic gyroscope from a bias phase modulator signal may be reduced or substantially avoided by transmitting one or more off-frequency signals having a frequency other than the eigenfrequency of the gyroscope towards a bias phase modulator, generating the bias phase modulator signal having a frequency substantially equal to the eigenfrequency of the gyroscope, and driving the bias phase modulator with the bias phase modulator signal.

Interferometric fiber optic gyroscope with off-frequency modulation signals

Apparatus and methods for performing a Fourier transform mechanically, using an array of one or more resonators. By tuning the resonators so that their natural frequencies correspond to harmonics of an input signal, the vibration of the resonators in response to the input signal may be measured to provide phase and amplitude information that is equivalent to the Fourier coefficients of the input signal. Preferably, the resonators are microelectromechanical (MEMS) resonators. Using MEMS resonators, the Fourier transform of a signal can be determined using substantially less power than would be consumed by a digital signal processor (DSP) or microprocessor performing similar calculations. MEMS resonator-based apparatus and methods according to various embodiments may be used for applications including compression and image processing.

Low-power signal processing using MEMS

Apparatus is used in sensing a measured input. The apparatus includes a capacitor with a capacitance that varies non-linearly in response to the measured input, and a circuitry that derives, from the capacitance, a signal that varies substantially linearly with the measured input. The capacitor includes a first electrode, a second electrode, and a gap defined by a space between the electrode. The circuitry includes an amplifier with a first input terminal in electrical communication with the first electrode, a second input terminal, and an output terminal in electrical communication with the second electrode. The capacitance of the capacitor varies as an inverse of the gap of the capacitor, the gap of the capacitor varies in response to changes in the measured input, and the signal is derived from an output of the amplifier.

Apparatus for and method of sensing a measured input

A fully integrated charge amplifier with DC stabilization includes a first amplifier having an input terminal and an output terminal, a first capacitor coupled between the input terminal and the output terminal of the first amplifier, a transimpedance amplifier having an input terminal coupled to the output terminal of the first amplifier and an output terminal, and an impedance device coupled between the input terminal of the first amplifier and the output terminal of the second amplifier. The impedance device has a resistance of at least 1 M&#x3a9;.

Charge amplifier device having fully integrated DC stabilization

Growing community of inventors

Dedham, MA, United States of America

Paul A Ward