Harston
Geoffrey Harston, Laurel, MD US
Patent application number | Description | Published |
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20120002211 | CHEMICAL SENSING WITH COHERENT DETECTION OF OPTICAL SIGNAL - This invention relates generally to the systems and methods for standoff trace chemicals detection such as explosives residue and others, and particularly to optical devices and the methods of their use based on sensing of gases and residue materials. This sensing includes detection and measurement of optical absorption spectra and relative concentration of the chemical followed by the chemical identification based on these spectral data. The sensing is based on photothermal interferometry method improved by implementation of coherent optical detection. The coherent optical detection is performed by an integrated polarization-diversity coherent receiver with an electro-optic phase modulator for a local oscillator optical beam. The implementation of pulsed probe sensing and local oscillator optical beams in the coherent detection improves the device with better eye safety performance. The hybrid calibration via a phase-modulated local oscillator optical beam allows optimizing the signal reception and reduces complexity of the probe subsystem. | 01-05-2012 |
Geofrey Harston, Laurel, MD US
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20090142051 | COHERENT OPTICAL DETECTOR AND COHERENT COMMUNICATION SYSTEM AND METHOD - An optical device is provided with first and second inputs. A first coupler coupled is coupled to the first input and produces at least a first and second output. A second coupler is coupled to the second input and produces at least a first and second output. A third coupler is coupled to the first output of the first coupler and to the first output of the second coupler. A fourth coupler is coupled to the second output of the first coupler and to the second output of the second coupler. First and second crossing waveguides are provided with an angle selected to minimize crosstalk and losses between the first and second cross waveguides. The first crossing waveguide connects one of the first or second outputs from the first coupler with an input of the fourth coupler. The second crossing waveguide connects one of the first or second outputs from the second coupler with an input of the third coupler. A first phase shifter is coupled to the first and second waveguides. The first and second waveguides connect one of the outputs of the first or second coupler and one of the inputs of the third or fourth couplers. The first, second, third and fourth couplers, the two crossing waveguides and the phase shifter are each formed as part of a single planar chip made of an electro-optical material. | 06-04-2009 |
John Christopher Harston, Clevedon GB
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20080227612 | Rotary Transfer Mechanism - A rotary transfer mechanism for transferring flat sleeve cartons ( | 09-18-2008 |
Stephen W. Harston, Andover, MA US
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20090284243 | AUTO-NULLED BANDGAP REFERENCE SYSTEM AND STROBED BANDGAP REFERENCE CIRCUIT - An auto-nulled bandgap reference system employing a substrate bandgap reference circuit with primary and auxiliary amplifiers and a switching circuit which in a first mode develops a voltage to null the offset and noise errors of the auxiliary amplifier and then in the second mode uses the nulled auxiliary amplifier to develop a voltage to null the offset and noise errors of the primary amplifier; and a strobe circuit including an output storage device and a strobe control circuit for periodically powering up a bandgap reference circuit to charge the output storage device and powering down the bandgap reference circuit to conserve power. | 11-19-2009 |
Stephen William Harston, Andover, MA US
Patent application number | Description | Published |
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20080218154 | Integrated energy metering system - An integrated energy metering system having an energy meter including a voltage ADC for sensing voltage, a current ADC for sensing current, a microcontroller; a first memory device for storing program data for the energy meter; and a plurality of circuit blocks; a voltage monitor for monitoring a primary power supply; a power supply switch circuit for selectively applying one of the primary and auxiliary power supplies to the energy meter; and a system controller responsive to the voltage monitor for operating the switch circuit to apply the auxiliary power supply when the primary power supply voltage decreases below a predetermined level and gating the power to a first class of circuit blocks in the energy meter and applying power continuously to a second class of circuit blocks. | 09-11-2008 |